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Administrative data

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records
Reference
Endpoint:
two-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Principles of method if other than guideline:
The study was conducted under the NTP Program's RACB protocol, the details of which have been published previously.
Triethylene glycol and two of its derivatives were evaluated for reproductive toxicity in a continuous breeding protocol with Swiss CD-1 mice. Triethylene glycol (TEG: 0, 0.3, 1.5, and 3%), triethylene glycol diacetate (TGD: 0, 0.75, 1.5, and 3%), and triethylene glycol dimethyl ether (TGDME: 0, 0.25, 0.5, and 1%) were administered in drinking water to breeding pairs (20 pairs per treatment group, 40 control pairs) during a 98-day cohabitation period. Reproductive function was assessed by the number of litters per pair, live pups per litter, proportion of pups born alive, and pup weight.
GLP compliance:
not specified
Limit test:
no
Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at study initiation: 6 weeks
- Housing: Throughout these studies, all animals were housed in solid-bottom polypropylene or polycarbonate cages with Ab-Sorb-Dri bedding. Male and female mice were group-housed by sex during quarantine and for the 1-week premating period. Subsequently, the animals were housed individually or as breeding pairs.
- Diet: Ground rodent chow (NIH-07)
- Water: deionized filtered water, ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 21 ± 0.5 °C
- Photoperiod (hrs dark / hrs light): 14/10
Route of administration:
oral: drinking water
Vehicle:
water
Details on exposure:
The treatment solutions for each test compound were independently formulated by mixing the test compound (w/v) directly into different proportions of distilled water. An aliquot of each formulation of each chemical in the drinking water and the control water and bulk chemical were sent to Midwest Research Institute at 6-week intervals for confirmation of dose levels and certification of the stability of the bulk chemical.
Details on mating procedure:
The test substance was administered in drinking water to breeding pairs (20 pairs per treatment group, 40 control pairs) during a 98-day cohabitation period.
Duration of treatment / exposure:
beginning 1 week before mating of the F0-generation until end of lactation period of the F2-generation
Frequency of treatment:
continuously
Details on study schedule:
Reproductive function was assessed by the number of litters per pair, live pups per litter, proportion of pups born alive, and pup weight.
Dose / conc.:
590 mg/kg bw/day (nominal)
Remarks:
0.3%
Dose / conc.:
3 300 mg/kg bw/day (nominal)
Remarks:
1.5%
Dose / conc.:
6 780 mg/kg bw/day (nominal)
Remarks:
3%
No. of animals per sex per dose:
- 20 animals per sex per dose group
- 40 animals per sex in the control group
Control animals:
yes, concurrent no treatment
Details on study design:
This study consists of 4 tasks:
Task 1 - dose-setting study
Task 2 - continuous breeding phase
Task 3 - crossover mating trial used to determine the affected sex when a positive effect on fertility is detected in Task 2
Task 4 - assesses the reproductive performance of the offspring from Task 2 breeding pairs
On the basis of the reduced body weight gain and increased mortality (12.5%) in the 5% test group, exposure levels of 0, 0.3, 1.5 and 3% TEG were selected for this study.
Parental animals: Observations and examinations:
Body weight, kidney weight, liver weight, mortality, food consumption, water consumption, clinical signs.
Oestrous cyclicity (parental animals):
Estrous cycle length
Sperm parameters (parental animals):
Sperm concentration, motility, and morphology
Litter observations:
Pup growth to weaning, mortality
Postmortem examinations (parental animals):
Litters/pair, live pups/litter, cumulative days to litter, absolute testes/epididymis weight, sex accessory gland weight, epidid. sperm parameters.
Statistics:
Statistical analysis was performed. The level of significance for all tests was set at p<0.05.
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
mortality observed, non-treatment-related
Description (incidence):
During Task 2, a total of 6 animals died - 2 females in the control, 1 male and 1 female in the 1.5% test group and 2 females in the 3% test group. The random distribution of deaths across treatment groups suggests that they were not treatment-related.
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed
Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
Description (incidence and severity):
TEG during Task 2 had no effect on fertility or reproductive performance as indicated by the proportion of pairs able to produce at least 1 litter, number of litters produced per pair, number of live pups per litter or proportion of pups born alive.
Since TEG exerted minimal effects on reproductive performance in the Task 2 parental mice (P generation), the effect of TEG on 2 -generation fertility was assessed. The exposure was continued and the final Task 2 litters (F1), of the control and 3% TEG groups were reared to maturity (74 +/- 10 days) and then these F1 offspring were mated to non-siblings from the same treatment group.
Dose descriptor:
NOAEL
Effect level:
6 780 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: overall effects
Critical effects observed:
no
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
no effects observed
Dose descriptor:
NOAEL
Effect level:
6 780 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: overall effects
Critical effects observed:
no
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Continuous exposure to 1.5 or 3% significantly reduced mean live pup weight compared to the corresponding weights in the 0 and and 0.3% test group
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
no effects observed
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
TEG significantly increased liver weight in males and when organ weights were adjusted for body weight, 3% TEG significantly increased female liver weight compared to controls.
Gross pathological findings:
no effects observed
Histopathological findings:
not examined
Other effects:
no effects observed
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
TEG had no adverse effects on the other reproductive parameters measured, including F1 litter size.
Necropsy of the F1 male offspring showed that the highest concentration had no effect on body weight, testis, epididymis, seminal vesicle, or prostate weight, epididymal sperm concentration, percentage motile sperm, or percentage morphologically abnormal sperm. Necropsy of the F1 females showed no change in body or liver weight. The weights of the brain, pituitary, ovary, oviduct, and uterus were similarly unaffected. In contrast, TEG significantly increased liver weight in males and when organ weights were adjusted for body weight, 3% TEG significantly increased female liver weight compared to controls.
Furthermore, similar to the P generation, continuous exposure of the F1 mice to 3% TEG affected neither the mating index nor the fertility index.
Generation:
F1
Remarks on result:
not determinable due to absence of adverse toxic effects
Critical effects observed:
no
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Mice from the final Task 2 litters were weighed at births and on day 21 and day 74 +/- 10, and no significant differences were observed.
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
no effects observed
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings:
not examined
Other effects:
no effects observed
Behaviour (functional findings):
no effects observed
Developmental immunotoxicity:
not examined
TEG had no adverse effects on the other reproductive parameters measured, including proportion of F2 pups born alive, sex of the F2 pups born alive, and adjusted F2 pup weight.
Generation:
F2
Remarks on result:
not determinable due to absence of adverse toxic effects
Critical effects observed:
no
Reproductive effects observed:
no

Effect of TEG on fertility and reproductive performance:

   0% TEG  0.3% TEG  1.5% TEG  3.0% TEG
 No. fertile/No. cohabited  37/37  19/20  18/18  18/18
 Litters/pair  4.8 +/- 0.1 (37)  4.8 +/-0.2 (19)  4.8 +/- 0.2 (18)  4.6 +/- 0.3 (18)
 Live pups/litter  11.7 +/- 0.4 (37)  12.2 +/- 0.5 (19)  11.7 +/- 0.6 (18)  10.9 +/- 0.7 (18)
 Proportions of pups born alive  0.96 +/- 0.02 (37)  0.98 +/-0.01 (19)  0.97 +/- 0.02 (18)  0.96 +/-0.03 (18)
 Live pup weight (g)  1.66 +/- 0.02 (37)  1.63 +/- 0.02 (19)  1.60 +/- 0.02 (18)*  1.59 +/- 0.02 (18)*

* Pairs of mice were cohabited and dosed with the appropoirate chemical for 14 weeks. Pairs were considered fertile if they produced one or more litters.

Effect of TEG on male body and organ weights and sperm parameters at necropsy (The 5th litter produced during Task 2 was allowed to grow until 74 +/- 10 days of age. They received either control or chemical treatment via lactation until weaning and then dosed with drinking water until necropsy at 95 +/- 10 days of age. Each value is the mean +/- SE of 20 mice. ND = parameter not determined.)

 Weight or sperm parameter  0 (control)  3%
 Body (g)  33.2 +/- 0.4  33.1 +/- 0.9
 Liver (g)  2.02 +/- 0.03  2.13 +/- 0.05*
 Kidneys/adrenals (g)  ND  ND
 Right testis (mg)  120 +/- 4  115 +/- 4
 Right epididymis (mg)  47 +/- 1  43 +/- 1
 Prostate (mg)  34 +/- 4  32 +/- 3
 Seminal vesicles (mg)  285 +/- 13  305 +/- 17
 Motile sperm (%)  52 +/- 7  54 +/- 5
 Abnormal sperm (%)  5.8 +/- 1.5  4.9 +/- 1.4
 Sperm concentration**  700 +/- 35  719 +/-38

* significantly different (p<0.05) from the control group

** No. sperm x 10(3)/mg caudal tissue

Effect of TEG on female body and organ weights at necropsy (The 5th litter produced during Task 2 was allowed to grow until 74 +/- 10 days of age. They received either control or chemical treatment via lactation until weaning and then dosed drinking water until necropsy at 95 +/- 10 days of age. Each value is the mean +/- SE of 20 animals.)

 Weight (g)  0 (control)  3%
 Body  30.4 +/- 0.5  29.4 +/- 0.6
 Liver  2.01 +/- 0.05  2.02 +/- 0.07
Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
6 780 mg/kg bw/day
Study duration:
subacute
Species:
mouse
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

The test substance was tested in a two-generation study (Bossert et al., 1992). Male and female mice were given the test substance via the drinking water in concentrations of 0.3, 1.5 and 3% (= 590, 3300 and 6780 mg/kg bw/day). The test substance was not a reproductive toxicant in either generation of mice when administered at concentrations of up to 3%, although developmental toxicity was noted in the first generation as reduced pup body weight. The NOAEL for the parental animals was found to be 6780 mg/kg bw/day; NOAEL for the F1 generation was also 6780 mg/kg bw/day.

Effects on developmental toxicity

Link to relevant study records

Referenceopen allclose all

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
according to guideline
Guideline:
other: EPA TSCA Testing Guidelines (1985; 1987)
GLP compliance:
yes (incl. QA statement)
Limit test:
no
Specific details on test material used for the study:
purity: > 99%
Species:
mouse
Strain:
CD-1
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Timed-pregnant dams were dosed daily with undiluted TEG or vehicle alone on gestation days 6 - 15. All treatments were administered by gavage. The dose volume was based on the dose group and the individual animals' most recent body weight. The doses employed based on results from a dose range-finding study, also performed on timed-pregnant mice. Vehicle control animals were dosed with deionized water at the top dose volume.
All females on study were weight on g.d. 0, 6, 9, 12, 15 and 18. Food and water consumption were measured at 3-day intervals throughout g.d. 0 - 18. All females were examined daily for clinical signs of toxicity. The treatment period for all study females was g.d. 6 - 15.
The gravid uterus, ovaries (including corpora lutea), cervix, vagina and abdominal and thoracic cavities were examined grossly. Ovarian corpora lutea af pregnancy were counted. Maternal liver and uterine weights were determined. Maternal kidneys were also weighed, and then bisected (left longitudinally, right transversely) and fixed in buffered neutral 10% formalin for possible subsequent histopathologic examination (kidneys from high-dose and control group dams were subsequently examined by light microscopy). The uterus was externally examined for signs of hemorrhage, removed from the abdominal cavity and dissected longitudinally to expose the contents. All live and dead fetuses and resorption sites were noted and recorded. Uteri from females that appeared non-gravid were placed in a 10% ammonium sulfide solution for detection of early resorptions.
Details on mating procedure:
Mice were mated 1:1 (one male:one female) in stainless steel wire-mesh cages (23.-5 cm:x 20.0 cm x 18 cm high) und the paperboard beneath the cages was checked daily for dropped copulation plugs. Each male was used only once in this study. Successfully mated (plug-positive) females were housed singly in animal room 147 for the duration of the study. The day a dropped copulation plug was found was desigated gestation day (gd) 0. Thirty plug positive females were assigned to each experimental group by a randomization procedure stratified by body weight such that all groups were equivalent in both mean body weight and body weight range on g.d. 0.
Duration of treatment / exposure:
gestation day 6 - 15
Frequency of treatment:
daily
Duration of test:
until g.d. 18
Dose / conc.:
0.5 other: mL/kg bw/day
Remarks:
Nominal concentration
Dose / conc.:
5 other: mL/kg bw/day
Remarks:
Nominal concentration
Dose / conc.:
10 other: mL/kg bw/day
Remarks:
Nominal concentration
No. of animals per sex per dose:
Total: 206
Control animals:
yes, concurrent vehicle
Details on study design:
Because of the lack of toxicity observed from a probe study, a dose (11,000 mg/kg) at approximately 11 times the limit test (1000 mg/kg) had to be used to produce maternal and fetal toxicity. At a dose approximately 6 times the limit test, fetal toxicity was observed. It is extremely unlikely that there is any reasonably foreseeable application or use at which humans would be exposed to such high levels of TEG.
Maternal examinations:
All females an study were weighed on gd 0, 6 (prior to onset of dosing), 9, 12, 15 (during the dosing period) and 18. Food and water consumption were measured at three-day intervals throughout gestation (gd 0-18). All females were examined daily for clinical signs of toxicity. The treatment period for all study females was gd 6 through 15.
Ovaries and uterine content:
The gravid uterus, ovaries (including corpora lutea), cervix, vagina and abdominal and thoracic cavities were examined grossly. Ovarian corpara lutea of pregnancy were counted. Maternal uterine weights were determined.
Fetal examinations:
All live fetuses were weighed and sexed. All fetuses were examined for external variations and malformations including cleft palate. All live fetuses in each litter were examined for thoracic and abdominal visceral ahnormallties by modification of methods described by Staple (1974). One-half of the live fetuses in each litter were decapitated and their heads ware fixed In Bouin's solution for examination of craniofacial structures by sectioning methods modified from Wilson (1973). All fetuses (50% intact, 50% decapitated) in each litter were eviscerated, fixed In ethanol, processed for skeletal staining with alizarin red S (Crary, 1962; Paltzer and Schareain, 1966), and examined for skeletal malformations and variations.
Statistics:
The unit of comparison was the pregnant female or the litter (Weil, 1970).
Results of the quantitative continuous variables (e.g. maternal body weights, organ weights, etc.) were intercompared for the three TEG-exposed groups and the vehicle control group by use of Levene's test for equal variances (Levene, 1960), analysis of variance (ANOVA), and t-tests with Bonferroni probabilities for pairwise comparisons. When Levene's test indicated homogeneous variances and the ANOVA was significant, the pooled t-test was used. When Levene's test indicated heterogeneous variances, all groups were compared by an ANOVA for unequal variances (Brown and Forsythe, 1974) followed, when necessary, by the separate variance t-test.
Nonparametric data obtained following laparohysterectomy were statiatically treated using the Kruskal-Wallis test (Sokal and Rohlf, 1969) followed by the Mann-Whitney U test (Sokal and Rohlf, 1969) when appropriate. Incidence data were compared using Fisher's Exact Test (Sokal and Rohlf, 1969). For all statistical tests, the probability value of p < of 0.05 (two-tailed) was used as the critical level for significance.
Clinical signs:
no effects observed
Description (incidence and severity):
Clinical observations of the dams were recorded daily. There were no statistically significant treatment-related clinical signs of toxicity. However, treatment-associated clinical signs were observed in 2 dams at 10.0 mL/kg/day. These included hypoactivity in both dams, and audible and rapid respiration in one dam.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
No females aborted or died prior to scheduled sacrifice. One female, at 10.0 mL/kg/day, delivered early (on g.d. 18), was euthanized, and removed from the study.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Periodic maternal body weights and body weight changes were statistically equivalent across treatment groups. No apparent trends (nonstatistically significant reductians) were observed at any exposure level. There were no treatment-related differences in maternal terminal body weight.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
Food consumption during gestation expressed as grams/dam/day was statistically equivalent among groups.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Description (incidence and severity):
Water consumption was equivalent among groups.
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
While not statistically significant, gravid uterine weight appeared reduced at 5.0 and 10.0 mL/kg/day. Corrected terminal body weight (body weight at sacrifice minus gravid uterine weight), corrected body weight change (gestational weight gain minus gravid uterine weight), liver weight (absolute and relative to corrected body weight) and absolute kidney weight were unaffected by treatment. Relative kidney weight was significantly increased at 10.0 mL/kg/day.
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
There were no treatment-related necropsy findings of the dams at scheduled sacrifice on g.d. 18. At 0.5 (but not 5.0 and 10.0) mL/kg/day dams exhibited a statistically increased incidence of cystic ovaries. Findings at 10.0 mL/kg/day involved 2 dams, one exhibiting small kidneys and one exhibiting clotted blood and colour change in a single amniotic sac. These findings were not considered to be treatment-related
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
Microscopic evaluation of maternal kidneys from the 0.0 and 10.0 mL/kg/day groups revealed no treatment-related histological changes.
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Number of abortions:
no effects observed
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
Percent preimplantation and postimplantation losses were equivalent across groups.
Total litter losses by resorption:
no effects observed
Early or late resorptions:
no effects observed
Dead fetuses:
no effects observed
Changes in pregnancy duration:
no effects observed
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): effects observed, non-treatment-related
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.DescriptionIncidenceAndSeverityEffectsOnPregnancyDuration): One female each at 0.0, 1.0 and 10.0 mL/kg/day and 2 females at 5.0 mL/kg/d contained only non-viable implants (early or late resorptions or dead fetuses) at scheduled sacrifice. A total of 25 - 28 litters containing one or more live fetuses were examined in each group.
Changes in number of pregnant:
no effects observed
Description (incidence and severity):
Pregnancy rate was equivalent for all dose groups, ranging from 90.0 - 96.7%.
Other effects:
no effects observed
Details on maternal toxic effects:
There was no effect of treatment on the number of ovarian corpora lutea, total, viable or non-viable (early and late resorptions and dead fetuses) implantations per litter or on sex ratio (percent males).
Key result
Dose descriptor:
NOEL
Effect level:
5 other: mL/kg bw/day
Based on:
test mat.
Basis for effect level:
organ weights and organ / body weight ratios
Key result
Abnormalities:
no effects observed
Fetal body weight changes:
effects observed, treatment-related
Description (incidence and severity):
Fetal body weights (all fetuses, male or female) per litter were significantly reduced at 5.0 and 10.0 mL/kg/day. Fetal body weights per litter at 0.5 mL/kg/day were equivalent to control values.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): effects observed, treatment-related
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): Fetal body weights (all fetuses, male or female) per litter were significantly reduced at 5.0 and 10.0 mL/kg/day. Fetal body weights per litter at 0.5 mL/kg/day were equivalent to control values.
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
no effects observed
Description (incidence and severity):
There no effect on sex ratio (percent males).
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
no effects observed
External malformations:
no effects observed
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
There were no statistical differences in the incidences of any individual malformations. A total of 78 different types of individual fetal skeletal variations were observed. Of these, six findings, cervical centra #1, #2, #3 and/or #4 poorly ossified, reduced number of caudal segments, poorly ossified frontal bone, poorly ossified supraoccipital bone, some proximal phalanges of the hindlimb poorly ossified and some proximal phalanges of the hindlimb unossified, exhibited significantly increased incidences at 10.0 mL/kg/day when compared to the control group. There was also a statistically significant increase in the incidence of poorly ossified supraoccipital and frontal at 5.0 mL/kg/day. There were no statistically increased individual skeletal variations at 0.5 mL/kg/day. There were no treatment-related increases in the incidence of variations by category (external, visceral or skeletal) or of total variations.
Visceral malformations:
no effects observed
Other effects:
no effects observed
Key result
Dose descriptor:
NOEL
Effect level:
0.5 other: mL/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
fetal/pup body weight changes
Key result
Abnormalities:
no effects observed
Key result
Developmental effects observed:
yes
Lowest effective dose / conc.:
0.5 other: mL/kg bw/day
Treatment related:
yes
Relation to maternal toxicity:
developmental effects in the absence of maternal toxicity effects
Dose response relationship:
yes
Relevant for humans:
not specified

Summary of effects seen by daily gavage of mice with undiluted TEG over the period of organogenesis:

 Effect

 Dosage (ml/kg)         
   0.0 = water control  0.5 ml/kg  5.0 ml/kg  10.0 ml/kg
 Gestational body weight change, dys 0 - 18 (g)*  30.90 +/- 7.47  29.63 +/- 6.58  28.35 +/- 8.44  27.59 +/- 6.94
 Maternal relative kidney weight (%)*  1.297 +/- 0.109  1.319 +/- 0.1290  1.353 +/- 0.1032  1.384 +/- 0.1435**
 Gravid uterine weight (g)*  20.729 +/- 6.056  20.303 +/- 4.900  19.631 +/- 6.057  18.562 +/- 4.980
 All fetuses  1.429 +/- 0.115  1.416 +/- 0.997  1.350 +/- 0.066**  1.303 +/- 0.098***
 - males  1.463 +/- 0.114  1.442 +/- 0.116  1.384 +/- 0.074**  1.332 +/- 0.106***
 - females  1.391 +/- 0.118  1.395 +/- 0.092  1.321 +/- 0.066**  1.271 +/- 0.102***

* results as mean +/- SD

** p<0.05 (compared to controls)

*** p<0.01 (compared to controls)

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
according to guideline
Guideline:
other: EPA TSCA Testing Guidelines (1985; 1987)
GLP compliance:
yes (incl. QA statement)
Limit test:
no
Species:
rat
Strain:
Sprague-Dawley
Details on test animals or test system and environmental conditions:
170 virgin male and 176 virgin female albino rats were used. All animals were quarantined for two weeks, during which time representative animals were subjected to fecal sampling, histologic examination of selected organs and to serum viral antibody examination. Rats were housed in stainless steel wire-mesh cages with food and water available ad libitum. Females and males were housed two per cage per sex during quarantine. All animals were assigned a unique number and received a stainless steel ear tag.
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Timed-pregnant dams were dosed daily with undiluted test substance or vehicle alone gestation day 6 - 15. The dose volume was based on the dose group and the dam's most recent body weight. The doses employed were 0.0, 1.0, 5.0 or 10.0 mL/kg/day based on results from a dose range-finding study. Vehicle control animals were dosed with water at the top dose volume of 10.0 mL/kg.
All females on study were weighed on gestation day 0, 6, 9, 12, 15 (during the dosing period) and day 18 and 21. Food and water consumption were measured at 3-day intervals throughout gestation. All females were examined daily for clinical signs of toxicity.
Details on mating procedure:
Rats were mated 1:1 (1 male/1 female) in stainless steel cages and the paperboard beneath the cages was checked for dropped copulation plugs. Each male was used only once in the study. Plug-positive females were housed only for the duration of the study. The day a copulation plug was found was designated gestational day 0.
25 plug-positive females were assigned to each experimental group by a randomization procedure stratified by body weight such that all groups were equivalent in both mean body weight and body weight range on gestation day 0.
Duration of treatment / exposure:
gestation days 6 - 15
Frequency of treatment:
daily
Duration of test:
21 days
Dose / conc.:
1 other: mL/kg bw/day
Remarks:
Nominal concentration
Dose / conc.:
5 other: mL/kg bw/day
Remarks:
Nominal concentration
Dose / conc.:
10 other: mL/kg bw/day
Remarks:
Nominal concentration
No. of animals per sex per dose:
Total: 170 males, 176 females
Control animals:
yes, concurrent vehicle
Details on study design:
The doses employed were 0.0, 1.0, 5.0 or 10.0 mL/kg bw/day based on results from a dose range-finding study also performed on timed-pregnant rats.
Maternal examinations:
Kidneys from high dose and control dams were examined by light microscopy.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Fetal examinations:
All live fetuses were weighed and sexed. All fetuses were examined for external malformations including cleft palate, and variations. All live fetuses in each litter were exarnined for thorarcic and abdominal visceral abnormalities by modification of methods described by Staples (1974).
One-half of the live fetuses (even-numbered fetuses from litters with an even number of live fetuses, odd-numbered fetuses from litters with an odd number of live fetuses in each litter were decapitated and their heads were fixed in Bouin's solution for examination of craniofacial structures by sectioning methods modified from Wilson (1965; 1973). All fetuses (50% intact, 50% decapitated) in each litter were eviscerated, fixed In ethanol, processed for skeletal staining with alizarin red S and examined for skeletal malformations and variations.
Statistics:
The unit of comparison was the pregnant female or the litter. Results of the quantitative continuous variables were intercompared for the three TEG-exposed groups and the vehicle control group by use of Levene's test for equal variances and t-tests with Bonferroni probabilities for pairwise comparisons. When Levene's test indicated homogeneous variances and the ANOVA was significant, the pooled t-test was used. When Levene's test indicated heterogeneous variances, all groups were compared by an ANOVA for unequal variances followed, when necessary, by the separate variance t-test.
Non-parametric data obtained following laparohysterectomy were statistically treated using the Kruskal-Wallis test followed by the Mann-Whitney U test when appropriate. Incidence data were compared using Fisher's Exact Test. For all statistical tests, the probability value of p <0.05 (two tailed) was used as the critical level of significance.
Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
There were no statistically significant treatment-related clinical signs of toxicity. However, treatment-associated clinical signs were observed in a few dams only at 10.0 mLl/kg/day; these included urine stains, audible respiration, periocular encrustation and perioral wetness.
Dermal irritation (if dermal study):
not examined
Mortality:
mortality observed, non-treatment-related
Description (incidence):
One female at 5.0 mL/kg/day died prior to scheduled sacrifice on g.d. 11. The cause of its death could not be determined. One control female delivered early (on g.d. 20) and was euthanized, and removed from study. Her data were eliminated from subsequent summarized results.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
- Periodic maternal body weights were significantly reduced at 10.0 mL/kg/day on gestational days 9, 12, 15 (during treatment) and 18 (post-treatment). At 5.0 mL/kg/day maternal body weight was significantly reduced following the treatment period on g.d. 18. Body weight gains were significantly reduced at 10.0 mL/kg/day for gestational days 6-9, 6-15 (the treatment period) and 0-21 (the gestational period). Body weight gains at 1.0 and 5.0 mL/kg/day were equivalent to control values.
- There were no treatment-related differences in maternal terminal body weight. However, corrected terminal body weight (body weight at sacrifice minus gravid uterine weight) and corrected body weight change (gestational weight gain minus gravid uterine weight) were significantly reduced in dams at 10.0 mL/kg/day.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Food consumption during gestation expressed in g/dam/d was significantly reduced at 10.0 mL/kg/d for g.d. 6 -9, 9 -12 and 12 -15 and for g.d. 6-15; at 5.0 mL/kg/day, food consumption was significantly reduced for days 6-9 of the treatment period.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
effects observed, treatment-related
Description (incidence and severity):
Increased water consumption was observed at 5.0 and 10.0 mL/kg/day for days 6-9, 9-12, 12-15 and 6-15. In addition, following treatment on days 15-18, water consumption was significantly increased at 10.0 mL/kg/day.
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
- There were no treatment-related differences in maternal terminal body weight or in gravid uterine weight.
- Liver weight (absolute and relative to corrected body weight) and absolute kidney weight were unaffected by treatment. Relative kidney weight, however, was significantly increased at 10.0 mL/kg/day.
Gross pathological findings:
no effects observed
Description (incidence and severity):
There were no statistically significant treatment-related necropsy findings in the dams at sacrifice on g.d. 21.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
Evaluation by light microscopy of maternal kidneys from the control and 10.0 mL/kg/day dose groups revealed no treatment-related lesions.
Histopathological findings: neoplastic:
no effects observed
Other effects:
no effects observed
Number of abortions:
no effects observed
Description (incidence and severity):
No females aborted.
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
Percent preimplantation and postimplantation loss were equivalent across groups.
Total litter losses by resorption:
no effects observed
Early or late resorptions:
no effects observed
Dead fetuses:
no effects observed
Changes in pregnancy duration:
not specified
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not specified
Changes in number of pregnant:
no effects observed
Description (incidence and severity):
Pregnancy rate was equivalent for all dose groups, ranging from 80.0-96.0%.
Other effects:
no effects observed
Details on maternal toxic effects:
All litters had one or more live fetuses at scheduled sacrifice. A total of 19 to 24 litters were examined in each group. There was no effect of treatment in the number of ovarian corpora lutea, total, viable or non-viable (early and late resorptions and dead fetuses) implantations per litter or on sex ratio (percent males).
Dose descriptor:
NOEL
Effect level:
1 other: mL/kg bw/day
Based on:
test mat.
Basis for effect level:
body weight and weight gain
food consumption and compound intake
organ weights and organ / body weight ratios
water consumption and compound intake
Abnormalities:
no effects observed
Fetal body weight changes:
effects observed, treatment-related
Description (incidence and severity):
Fetal body weights (all fetuses, male or female) per litter were significantly reduced at 10.0 mL/kg/day.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): effects observed, treatment-related
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): Fetal body weights (all fetuses, male or female) per litter were significantly reduced at 10.0 mL/kg/day.
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
no effects observed
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
no effects observed
External malformations:
no effects observed
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
- There were no statistical differences in the incidences of any individual malformations. However, the incidence of unilateral rudimentary rib #13 (on thoracic arch #13) at 10.0 mL/kg/day was 4.6 times that observed in control fetuses.
- The total number of fetuses with skeletal malformations appeared slightly increased in the highest dose. A total of 95 different types of fetal skeletal variations were observed. Of these, only one bilobed thoracic centrum #10, exhibited a significantly increased incidence at 10.0 mL/kg/day when compared to the control group. There was also one statistically significant reduction in the incidence of unossified sternebra #5 at 1.0 mL/kg/day. While not statistically significant, there were apparent increases in the incidences of several other individual skeletal variations involving reduced ossification in bones of the thoracic region at 10 mL/kg/day. These included increased incidences of poorly ossified thoracic centra #10, #11, #12 and #13, bilobed thoracic centra #1 and #13, short rib #13 and callused ribs. In addition, although observed only in one fetus at 10 mL/kg/day, poorly ossified thoracic arches (#13) is an uncommon finding.
Visceral malformations:
no effects observed
Other effects:
no effects observed
Dose descriptor:
NOEL
Effect level:
5 other: mL/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
fetal/pup body weight changes
Abnormalities:
no effects observed
Developmental effects observed:
yes
Lowest effective dose / conc.:
10 other: mL/kg bw/day
Treatment related:
yes
Relation to maternal toxicity:
developmental effects as a secondary non-specific consequence of maternal toxicity effects
Dose response relationship:
yes
Relevant for humans:
not specified
Conclusions:
Administration of triethylene glycol by gavage to timed-pregnant rats during organogenesis at 0.0, 1.0, 5.0 or 10.0 mL/kg/day resulted in maternal toxicity at 5.0 and 10.0 mL/kg/day and fetotoxicity at 10.0 mL/kg/day. There was a slight treatment-related increase in the incidence of two minor skeletal malformations at 10.0 mL/kg/day. The no observable effect level (NOEL) for maternal toxicity was 1.0 mL/kg/day, and the NOEL for developmental toxicity was 5.0 mL/kg/day.
Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: reliable study according to OECD guideline and GLP, but performed on a read-across substance
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes
Limit test:
no
Specific details on test material used for the study:
- Name of test material (as cited in study report): diethylene glycol
- Analytical purity: > 99.7% before the beginning of the study and 98.8% in the reanalysis after the end of the study.
- Stability: stability of the test substance over > 2 years was proven
Species:
rabbit
Strain:
Himalayan
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: the sexually mature, virgin Himalayan rabbits (Chbb: HM (outbred strain)) were supplied by Karl THOMAE, Biberach an der Riss, Germany
- Age at study initiation: 24 and 29 weeks old
- Weight at study initiation: mean body weight of pregnant animals only, ca. 2560 g (calculated from the means of the groups)
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
The test substance was administered to the animals orally (by gavage) once a day during the period of major organogenesis (day 7 to day 19 p.i.) always at approx. the same time of day (in the morning). The volume administered each day was 10 mL/kg body weight. The calculation of the volume administered was based on the individual body weight determined at the beginning of the administration period (day 7 p.i.). On day 29 p.i. all animals were sacrificed and examined macroscopically. The fetuses were dissected from the uterus, and further investigated with different methods. The test substance solutions were prepared only once for each study section because the stability of the test substance solution over a period of 21 days had been proven before treatment of the animals began. For the preparation of the solutions an appropriate amount of the test substance was weighed and subsequently dissolved in doubly distilled water. Due to technical reasons the study was carried out in 3 sections. Each dose group was represented in each section. A treatment interval of 7 days elapsed before the next section.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The stability of the test substance solutions over a period of 21 days could be demonstrated. The results of the analyses of the solutions of test substance confirmed the correctness of the prepared concentrations.
On the basis of the duration of use and the analytical findings the rabbit food used was found to be suitable. Federal Register, Vol. 44, No. 91, of May 9, 1979, p. 27354 (EPA), served as a guideline for maximum tolerable contaminants.
On the basis of the analytical findings, the drinking water was found to be suitable. German Drinking Water Regulation of May 22, 1986 served as a guideline for maximum tolerable contaminants.
Details on mating procedure:
After an acclimatization period of at least 5 days, the does were fertilized by means of artificial insemination.
This implied that 0.2 mL of a synthetic hormone which releases LH and FSH from the anterior pituitary lobe were injected intramuscularly to the female rabbits about 1 hour before insemination. The pooled ejaculate samples used for the artificial insemination were derived from male Himalayan rabbits of the same breed as the females.
The male donors were kept under conditions (air conditioning, diet, water) comparable to those of the females participating in this study.
The day of insemination was designated as day 0 (beginning of the study) and the following day as day 1 post insemination (p.i.).
Duration of treatment / exposure:
gestation day 7 - 19
Frequency of treatment:
daily
Duration of test:
30 days
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
400 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
15
Control animals:
yes, sham-exposed
Details on study design:
Based on the results of a dose range-finding study, the following doses were selected for the prenatal toxicity study in rabbits:
- 100 mg/kg bw: should constitute the expected no observable effect level
- 400 mg/kg bw: with this dose marginal influences on dams and/or fetuses could not be ruled out
- 1000 mg/kg bw: with this dose signs of maternal toxicity (e.g. retarded body weight gain) may possibly have occurred. A higher dose level was not deemed to be necessary due to the recommendations in the test guidelines, which had to be taken into account.
Maternal examinations:
The consumption of food was determined daily during the entire study period. All animals were weighed on days 0, 2, 4, 7, 9, 11, 14, 16, 19, 21, 23, 25 and 29 p.i.. The body weight change of the animals was calculated from these results. Furthermore, after terminal sacrifice the corrected body weight gain was calculated (body weight on day 29 p.i. minus body weight on day 7 p.i. minus weight of the uterus before it was opened). The animals were examined for clinical symptoms at least once a day, or more often when clinical signs of toxicity were elicited. Mortality: A check was made twice a day on working days or once a day (Saturday, Sunday or on public holidays).
Examinations of the dams at termination: On day 29 p.i. the dams were sacrificed by intravenous injection of a pentobarbital and the fetuses were dissected from the uterus. After the dams had been sacrificed, they were necropsied and assessed by gross pathology. The uterus and the ovaries were removed and the following data were recorded: - Weight of uterus before it was opened - Number of corpora lutea - Number and distribution of implantation sites classified as: --live fetuses --dead implantations: a) early resorptions (only decidual or placental tissues visible or from uteri from apparently non-pregnant animals and the empty uterus horn in the case of single-horn pregnancy) b) late resorptions (embryonic or fetal tissue in addition to placental tissue visible) c) dead fetuses (hypoxemic fetuses which did not breathe spontaneously after the uterus had been opened).
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
Examination of the fetuses after dissection from the uterus: At necropsy each fetus was weighed and examined macroscopically for any external findings. Furthermore, the viability of the fetuses and the condition of the placentae, the umbilical cords, the fetal membranes and fluids were examined. Individual placental weights were recorded. Soft tissue examination of the fetuses: After the fetuses had been sacrificed by C02, the abdomen and thorax were opened in order to be able to examine the organs in situ before they were removed . The heart and the kidneys were sectioned in order to assess the internal structure. The sex of the fetuses was determined by internal examination of the gonads. If heads of fetuses revealed severe findings (e.g. anophthalmia, microphthalmia, hydrocephalus, or cleft palate), the heads of these fetuses were severed from the trunk, fixed in BOUIN´s solution and later processed and assessed according to WIISON´s method. About 10 transverse sections were prepared per head. Skeletal examination of the fetuses: After the soft tissue examination all fetuses were placed in ethyl alcohol for staining of the skeletons. The stained skeletons were placed on an illuminated plate and examined, evaluated and assessed.
Statistics:
The data were evaluated statistically using the computer systems of the Department of Toxicology of BASF Aktiengesellschaft (laboratory data processing, responsible:Dr. H.D. Hoffmann). Examinations of dams and fetuses: Dunnett's Test was used for statistical evaluation of food consumption, body weight, body weight change, corrected body weight gain (net maternal body weight change), weight of the uterus before it was opened, weight of fetuses, weight of placentae, corpora lutea, implantations, pre- and postimplantation loss, resorptions and live fetuses. Fisher´s Exact Test was used for statistical evaluation of conception rate, mortality (of the dams) and all fetal findings. Significances resulting from these tests have been indicated in the tables (a for p < 0 .05, b for p < 0 .01).
Historical control data:
yes
Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
Except one doe of test group 1 (100 mg/kg body weight/day), which showed a marked edema in the anogenital region during days 16 - 29 p.i. and one animal of test group 2 (400 mg/kg body weight/day), which had an accidental lesion of the left hindlimb (days 17 - 29 p.i.), there were no remarkable clinical observations in any doe of all groups. Both recorded clinical observations are spontaneous ones and are not related to the test substance administration.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
There were no mortalities.
Body weight and weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
There were no adverse effects on body weights or body weight changes which could be attributed to the test substance administration. All values are within the range of biological variation or of spontaneous nature, including the statistically significant decrease in mean body weight change of the intermediate dose females during days 0 - 29 p.i. (whole study period). The results of the corrected body weight gain (body weight on day 29 p.i. minus body weight on day 7 p.i. minus weight of the uterus before it was opened) do not clearly show any dose-related differences between the groups. The only statistically significant difference in comparison to the controls, the low value in test group 2 (400 mg/kg body weight/day), which is mainly caused by 2 does, is without biological relevance.
Food consumption and compound intake (if feeding study):
effects observed, non-treatment-related
Description (incidence and severity):
Food consumption of the substance-treated does was not influenced by the test substance administration. The observable differences between the control animals and the dams of test groups 1 - 3 (100, 400 and 1,000 mg/kg body weight/day), including the statistically significantly increased food consumption in the highest dose group on days 6 - 7 p.i. (pretreatment period), are without biological significance.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Number of abortions:
no effects observed
Pre- and post-implantation loss:
effects observed, non-treatment-related
Total litter losses by resorption:
no effects observed
Early or late resorptions:
no effects observed
Dead fetuses:
no effects observed
Changes in pregnancy duration:
no effects observed
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed
Changes in number of pregnant:
no effects observed
Other effects:
effects observed, non-treatment-related
Description (incidence and severity):
There were no substantial differences concerning the uterus weights between the controls and the substance-treated groups. All values lie within the range of biological variation. Due to a technical error, the uterus weight of doe of test group 3 (1,000 mg/kg body weight/day) was not recorded. The conception rate varied between 93 and 100%. Concerning all groups, there were no substance-related and/or statistically significant differences in the conception rate, in the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation loss, the number of resorptions or viable fetuses. The differences evident are considered to be incidental and within the normal range of deviations for animals of this strain and age. This includes the one doe of test group 1 (100 mg/kg body weight/day) which did not become pregnant due to a hydrometra in the one and a blind ending uterine on the other side.
Key result
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: overall effects
Key result
Abnormalities:
no effects observed
Fetal body weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
There were no clearly dose-related or statistically significant differences between the groups concerning the mean fetal weights. All values are still within the range of biological variation; therefore the observable differences between the control and the substance-treated groups are assessed as to be of spontaneous nature.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not examined
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
effects observed, non-treatment-related
Description (incidence and severity):
The sex distribution in test groups 1 - 3 (100 - 1,000 mg/kg body weight/day) was comparable with the control group. The observable differences are without any biological relevance.
Changes in litter size and weights:
not examined
Changes in postnatal survival:
not examined
External malformations:
effects observed, non-treatment-related
Description (incidence and severity):
The external examination of the fetuses revealed no malformations in any group and only one kind of variation (pseudoankylosis) in 2 fetuses each of the control group, of test groups 2 (400 mg/kg body weight/day) and 3 (1,000 mg/kg body weight/day). There were no so-called unclassified observations (like placentae fused) in any fetus.
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Various malformations of the ribs and/or the vertebral column were seen in 1 fetus of the control and the 400 mg/kg group and in 3 fetuses of the 1,000 mg/kg group. No other skeletal malformations were recorded for any group. The variations elicited were related to the skull (splitting of skull bones, epactal bone between nasal and frontal bones), the ribs (accessory ribs, flying ribs, or rudimentary cervical ribs), the vertebral column (accessory thoracic vertebra) and the sternum (sternebra(e) of irregular shape, fused or bipartite) and were found in all groups without a clear dose-response relationship and/or without any statistically significant differences between the groups. In all groups signs of retardations (incomplete or missing ossification of skull bones, sternebra(e), and/or talus) were found; they occurred without any differences of biological relevance between the groups.
Visceral malformations:
effects observed, non-treatment-related
Description (incidence and severity):
The examination of the organs of the fetuses revealed two types of malformations. One high dose fetus showed a septal defect, a rather common finding in the rabbit strain used; this malformation is also present in the historical control data to about the same extent. Furthermore, two control fetuses and one fetus of the 400 mg/kg group had an agenesia of the gallbladder. Variations were detected in each group including the control. The very common finding (separated origin of carotids) in the rabbit strain used in this study occurred without a clear dose-response relationship, but was more frequently seen in the substance-treated groups, the differences in relation to the control being statistically significant ; however, if the relevant values of the substance-treated groups are compared with the corresponding historical control values, these values are within the range of biological variation. Therefore, it becomes obvious, that the number of control fetuses with this finding is unexpectedly low. The statistically significantly increased number of fetuses of test groups 1 - 3 (100, 400 and 1,000 mg/kg body weight/day) is therefore assessed as to be of incidental nature. The other variations (hypoplasia of gallbladder, dilated renal pelvis, ovary bipartite) occur without a dose-response relationship and/or are to be found in the same kind of magnitude in the historical control data. Moreover, several fetuses out of test groups 0 - 3 (0, 100, 400 or 1,000 mg/kg body weight/day) showed focal liver necrosis or blood coagula around the bladder (socalled unclassified observations).
Other effects:
effects observed, non-treatment-related
Description (incidence and severity):
The mean placental weights in the substance-treated groups (100, 400 and 1,000 mg/kg body weight/day) were not substantially influenced. The differences observed in comparison to the control are without biological relevance and lie within the range of biological variation.
Key result
Remarks on result:
not determinable due to absence of adverse toxic effects
Key result
Abnormalities:
no effects observed
Key result
Developmental effects observed:
no
Conclusions:
In conclusion, the oral administration of diethylene glycol to pregnant Himalayan rabbits by stomach tube on day 7 through day 19 p.i. in dosages of 100, 400 and 1,000 mg/kg body weight/day led to no adverse effects which can be causally related to the test substance administration in both the does and in the fetuses. The observable differences between the control group and the substance-treated groups appeared either without a clear dose-response relationship and/or were assessed as being without biological relevance, because the relevant values/findings are to be found in a similar range within the historical control data.
Summarized, diethylene glycol caused, under the conditions of this study, up to and including a dose of 1,000 mg/kg body weight/day no signs of maternal toxicity and no signs of embryo-/fetotoxicity; especially no teratogenic effects could be detected. As to the OECD GUIDELINE for testing of chemicals (No. 414, adopted May 12, 1981) in the case of substances of low toxicity (i.e. "if a dose level of at least 1,000 mg/kg body weight/day produces no evidence of embryotoxicity or teratogenicity") further embryotoxicity studies at higher dose levels may not be considered necessary.
Effect on developmental toxicity: via oral route
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
565 mg/kg bw/day
Study duration:
subacute
Species:
mouse
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

The test substance was tested by gavage in rats. Doses of 1, 5 and 10 mL/kg bw were given to time-pregnant rats from gestation day 6 - 15 (study duration: 21 days). Maternal toxicity was seen at 5 and 10 mL/kg bw and fetotoxicity was observed at 10 mL/kg bw/day. There was a slight treatment-related increase in the incidence of two minor skeletal malformations at the high dose group. The NOEL for maternal toxicity was 1 mL/kg bw/day, and the NOEL for developmental toxicity was 5 mL/kg bw/day (BRRC, 1991).

A developmental toxicity study with mice was reported (BRRC, 1990). Time-pregnant mice were given concentrations of 0.5, 5 and 10 mL/kg/d from gestation day 6 -15 via gavage (study duration: until gestation day 18). The administration of the test substance resulted in maternal toxicity at 10 mL/kg/d and fetotoxicity at 10 and 5 mL/kg/d. The ratio of the adult lowest observable effect level to the developmental lowest observable effect level was greater than 1 indicating preferential susceptibility of the developing mouse fetus to the test substance under these study conditions. The NOEL for maternal toxicity was 5 mL/kg bw/day (5650 mg/kg bw/day) and the NOEL for developmental toxicity was 0.5 mL/kg bw/day (565 mg/kg bw/day).

For developmental toxicity in rabbits, read-across from DEG was employed. Prenatal toxicity of orally administered DEG in rabbits was investigated in a study according to OECD TG 414 (BASF, 1989; Hellwig et al., 1995). DEG was administered by gavage to pregnant rabbits in daily doses of 100, 400 and 1000 mg/kg bw /day. From G7 through GD 19. Treatment-related effects on body weight parameters or clinical signs were not observed in the dams at any dose. Necropsy did not reveal any findings associated with the test item, and the gestational parameters were not significantly altered in the treated groups vs. the control group. Up to and including a dose of 1000 mg/kg bw/day, no signs of embryo-/fetotoxicity were observed; especially no teratogenic effects could be detected.

Justification for classification or non-classification

The test substance does not affect the reproductive performance and fertility, and neither possesses an embryo/fetotoxic nor a teratogenic potential. Based on the available information classification for reproductive toxicity is not warranted in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation No. (EC) 1272/2008.

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