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Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Justification for type of information:
Data from secondary source

Data source

Reference
Reference Type:
other: secondary source
Title:
One generation reproduction developmental toxicity study in Wistar rats
Author:
European Food Safety Agency (EFSA)
Year:
2010
Bibliographic source:
Additional Report to the DAR for test material ,2010

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
Principles of method if other than guideline:
One generation reproductive toxicity study of test material was performed on male and female Wistar rats.
GLP compliance:
not specified
Limit test:
no
Justification for study design:
No data available

Test material

Constituent 1
Chemical structure
Reference substance name:
2-naphthyloxyacetic acid
EC Number:
204-380-0
EC Name:
2-naphthyloxyacetic acid
Cas Number:
120-23-0
Molecular formula:
C12H10O3
IUPAC Name:
2-naphthyloxyacetic acid
Details on test material:
- Name of test material: 2-naphthyloxyacetic acid
- Molecular formula: C12H10O3
- Molecular weight: 202.208 g/mol
- Substance type: Organic

Test animals

Species:
rat
Strain:
Wistar
Details on species / strain selection:
No data available
Sex:
male/female
Details on test animals or test system and environmental conditions:
No data available

Administration / exposure

Route of administration:
oral: feed
Type of inhalation exposure (if applicable):
not specified
Remarks on MMAD:
No data available
Vehicle:
not specified
Details on exposure:
No data available
Details on mating procedure:
No data available.
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
No data available
Duration of treatment / exposure:
Males were treated for 10 weeks before mating and during the mated period and females for at least two weeks before mating, during 3 weeks of mating and pregnancy till the 21st day of lactation. The dams were allowed naturally deliver after mating and necropsied with their offspring on the 21st day of lactation.
Frequency of treatment:
daily
Details on study schedule:
No data available
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Dose / conc.:
100 mg/kg bw/day
Dose / conc.:
500 mg/kg bw/day
Dose / conc.:
2 500 mg/kg bw/day
No. of animals per sex per dose:
Total:200
0 ppm:25 male and 25 female
100ppm:25 male and 25 female
500ppm:25 male and 25 female
2500 ppm:25 male and 25 female
Control animals:
yes
Details on study design:
No data available
Positive control:
No data available

Examinations

Parental animals: Observations and examinations:
Parental animals observation and examinations
CAGE SIDE OBSERVATIONS: yes

DETAILED CLINICAL OBSERVATIONS: Yes
Time schedule: daily

BODY WEIGHT: Yes
Time schedule for examinations: Body weights were recorded weekly during gestation period and at days 1, 4, 7, 14 and 21 during lactation period.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes Food consumption was measured weekly during experimental period. Food intake was recorded on presumed gestation days 7, 14 and 20 and on lactation days 4, 7, 14, 18 and 21.
Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
Time schedule for examinations
Oestrous cyclicity (parental animals):
No data available
Sperm parameters (parental animals):
Yes, sperm morphology, caunt and motility were recorded.
Litter observations:
At birth, the number of pups born, sex and body weight of individual pups on days 1 and 4 were recorded. After standardization of litter size to 8 pups, pups were weighed individually on days 7, 14 and 21 of lactation. On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination. Fertility index for dams, sires and pup survival index were calculated.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving males were sacrificed shortly after the 3 weeks of mating period.
- Maternal animals: The dams were sacriced with their offspring on the 21st day of lactation.
GROSS NECROPSY: Yes. The following tissues and organs were preserved in 10% neutral buffered formalin and submitted to microscopic examination: grossly abnormal tissues, ovaries, uterus, vagina, testes, epididymides, seminal vesicles, prostate, coagulating glands, pituitary gland and target organs of all parental animals. The number of corpora lutea and implantation sites were recorded for all the dams.
HISTOPATHOLOGY / ORGAN WEIGHTS: Yes
Histopathological examination of the parents was initially restricted to preserved organs from control and high dose group animals.



Postmortem examinations (offspring):
SACRIFICE
On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination.
Statistics:
All quantitative variables like body weight and feed intake data were analysed by one-way ANOVA. Comparison of means between treatment groups and vehicle control group were done using Dunnett’s test if the overall treatment ‘F’ test was found to be significant. Pre-implantation loss, post implantation loss, number of corpora lutea, implantations, pre-coital interval and litters size (number) were analysed by one-way ANOVA after suitable transformation. Dunnett’s pair-wise comparison of the treated means with the control mean was done if the group differences were found significant. Z test was performed for testing the differences in proportions for mating and fertility indices and survival indices.
Reproductive indices:
Yes, Fertility index for male and female animals were calculated.
Offspring viability indices:
yes

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
not specified
Dermal irritation (if dermal study):
not specified
Mortality:
not specified
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
There were significant lower body weights from control at high dose in males from weeks 2 to 6 and at week 8 associated with a significant lower food intake at weeks 2 and 8 at high dose in males. There was also a significant decrease in bodyweights at day 20 of the gestation period in females of the high dose group, also observed at days 4, 7 and 14 of lactation period
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
effects observed, non-treatment-related
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
There were no test item related microscopic changes in males and females. All single or few incidences of microscopic findings observed in males and females were considered as incidental findings.
Histopathological findings: neoplastic:
not specified
Other effects:
not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not specified
Reproductive function: sperm measures:
no effects observed
Description (incidence and severity):
There were no test item related changes in sperm motility, cauda epididymal sperm counts and sperm morphology parameters. However, a statistically significant increase in percentage of abnormal sperms was observed in high dose males but this observed change was within the historical control data. Moreover, no fertility parameters were affected and there were no changes in the testes or epididymis grossly or histopathologically therefore, considered incidental and not related to the treatment.
Reproductive performance:
no effects observed

Effect levels (P0)

open allclose all
Dose descriptor:
NOAEL
Effect level:
153.8 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
2500ppm
Sex:
male
Basis for effect level:
body weight and weight gain
food consumption and compound intake
organ weights and organ / body weight ratios
gross pathology
reproductive function (sperm measures)
reproductive performance
Remarks on result:
other: No effects on reproductive performance were observed.
Dose descriptor:
NOAEL
Effect level:
393.6 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks:
2500 ppm
Sex:
female
Basis for effect level:
body weight and weight gain
food consumption and compound intake
organ weights and organ / body weight ratios
gross pathology
reproductive performance
Remarks on result:
other: no effects on reproductive performance
Dose descriptor:
LOAEL
Effect level:
2 500 ppm (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
body weight and weight gain
food consumption and compound intake
Remarks on result:
other:
Remarks:
Significantly reduced bodyweight in the presence of reduced food consumption

Target system / organ toxicity (P0)

Critical effects observed:
not specified
System:
other: not specified
Organ:
not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:
not specified
Dermal irritation (if dermal study):
not specified
Mortality / viability:
no mortality observed
Description (incidence and severity):
The mean number of male, female and total pups per litter at all the doses tested were unaffected by treatment
Body weight and weight changes:
no effects observed
Description (incidence and severity):
The weight of male, female pups per litter at all the doses tested were unaffected by treatment
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
no effects observed
Histopathological findings:
not specified
Other effects:
no effects observed
Description (incidence and severity):
No treatment-related changes were observed in the data of pups up to lactation day 21 at all the doses tested.

Developmental neurotoxicity (F1)

Behaviour (functional findings):
not specified

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not specified

Effect levels (F1)

open allclose all
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
153.8 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
viability
mortality
body weight and weight gain
gross pathology
Remarks on result:
other: No developmental toxic effects were observed
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
393.6 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
viability
mortality
body weight and weight gain
gross pathology
Remarks on result:
other: No developmental toxic effects were observed

Target system / organ toxicity (F1)

Critical effects observed:
not specified
System:
other: not specified
Organ:
not specified

Overall reproductive toxicity

Reproductive effects observed:
not specified
Treatment related:
not specified

Applicant's summary and conclusion

Conclusions:
The No Observed Adverse Effect Level (NOAEL) for maternal and developmental toxicity was considered as 2500 ppm which is equivalent to 153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females, when male and female Wistar rats were treated with 2-naphthyloxyacetic acid orally over one generation. The LOAEL for systemic toxicity was set as 2500 ppm (153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females) based on the significant reduction in body weight and food consumption in the high-dose group in both sexes.
Executive summary:

A one generation reproductive toxicity study of the test chemical was performed according to OECD Guideline 415in male and female Wistar rats. The test material wa smixed in diet at concentrations of0, 100, 500 and 2500 ppm and administered to group of 25 rats/sex/dose group. Males were treated for 10 weeks before mating and during the mated period and females for at least two weeks before mating, during 3 weeks of mating and pregnancy till the 21stday of lactation. The dams were allowed naturally deliver after mating and necropsied with their offspring on the 21stday of lactation.Body weights were recorded weekly during gestation period and at days 1, 4, 7, 14 and 21 during lactation period. Food consumption was measured weekly during experimental period. Food intake was recorded on presumed gestation days 7, 14 and 20 and on lactation days 4, 7, 14, 18 and 21. At birth, the number of pups born, sex and body weight of individual pups on days 1 and 4 were recorded. After standardization of litter size to 8 pups, pups were weighed individually on days 7, 14 and 21 of lactation. On day of weaning sacrifice (day 21), only one randomly selected pup per sex per litter was submitted to macroscopic examination. Fertility index formales and femalesand pupsurvival index were calculated. On completion of the gross pathology examination, the following tissues and organs were preserved in 10% neutral buffered formalin and submitted to microscopic examination: grossly abnormal tissues, ovaries, uterus, vagina, testes, epididymides, seminal vesicles, prostate, coagulating glands, pituitary gland and target organs of allparentalanimals. The number of corpora lutea and implantation sites were recorded for all the dams. Histopathological examination of the parents was initially restricted to preserved organs from control and high dose group animals.There were significant lower body weights from control at high dose (2500 ppm) in males from weeks 2 to 6 and at week 8 associated with a significant lower food intake at weeks 2 and 8 at high dose in males. In females a significant decrease in body weights was observed at day 20 of the gestation period at 2500 ppm group, and at days 4, 7 and 14 of lactation period. A statistically significant increase in relative kidney weights at 500 and 2500 ppm in males and at 2500 ppm for males and females was observed. However, the increased kidney weights observed in males and females were minimal in nature (<12%) and were not associated with microscopic changes, hence considered as toxicologically insignificant changes. The relative weight of epididymides increased significantly at 2500 ppm in males but with no related microscopic changes in left epididymides. Further, there were no corresponding change in the weight of right cauda epididymides and epididymal sperm count, therefore the increased epididymal weights were considered as incidental changes. There were no test item related changes in sperm motility, cauda epididymal sperm counts and sperm morphology parameters. In the 2500 ppm group, a statistically significant increase in percentage of abnormal sperms was observed, although this observed change was within the historical control data. Moreover, no fertility parameters were affected and there were no changes in the testes or epididymis grossly orhistologically.No test chemical-related gross and microscopic changes were found in males and females at any dose groups.The mean number and weight of male, female and total pups per litter at all the doses tested were unaffected by treatment. No treatment-related changes were observed in the data of pups up to lactation day 21 at all the doses tested. As no changes of toxicological significance noted among the rats that received dietary administration of the test chemical over one generation up to the dose level of 2500 ppm which, is equivalent to 153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females, this dose level is considered to be NOAEL for systemic and reproductive toxicity in parental animals and toxicity to offspring, under the test conditions and doses employed. The LOAEL for systemic toxicity was set as 2500 ppm (153.8 mg/kg body weight/day for males and 393.6 mg/kg body weight/day for females) based on the significant reduction in body weight and food consumption in the high-dose group in both sexes.