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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
publication
Title:
Effects of in utero and postnatal sodium saccharin exposure on the nutritional status of the young rat. II. Dose response and reversibility.
Author:
E. M. GARLAND, R. SHAPIRO*, P. L. KRAFT~', B. J. MATTSON, J. M. PARR and S. M. COHEN
Year:
1991
Bibliographic source:
Food Chem Toxicol. 1991, Oct; 29(10):669-79.

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other:
Principles of method if other than guideline:
Effects of in utero and postnatal test chemical exposure exposure were assessed in one generation of Sprague-Dawley Rats.
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
- Name of test material: Sodium Saccharine
- Molecular formula:C7H5NO3S•Na
- Molecular weight : 205.2 g/mol
- Substance type: Organic
- Physical state: Solid
Specific details on test material used for the study:
- Molecular formula:C7H5NO3S•Na
- Molecular weight : 205.2 g/mol
- Substance type: Organic
- Physical state: Solid

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
Details on test animal & Environmental conditions
- Source: Charles River Breeding Laboratories Inc.,
- Age at study initiation: 4 wk old
- Housing: Polycarbonate cages with corncob bedding
- Diet (e.g. ad libitum): Purina Rodent Chow No. 5002
- Water (e.g. ad libitum): distilled water
- Acclimation period: 2 wk

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 71 +_5°F
- Humidity (%): 50 +_ 20%.
- Photoperiod (hrs dark / hrs light): 12-hr light/dark schedule.




















Administration / exposure

Route of administration:
oral: feed
Vehicle:
other: Purina Rodent Chow No. 5002
Details on exposure:
The test chemical was mixed in the diet at concentrations of 0, 1, 3 or 7.5% by weight
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Dietary levels of the test chemical were analyzed by HPLC. Before each batch of test diet was fed.
Details on mating procedure:
Mating was started after 4-5 wk of test diet feeding.
Duration of treatment / exposure:
90 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 1, 3 or 7.5% by weight (0,1000,3000,7500 mg/kg bw/day)
Basis:
nominal in diet
No. of animals per sex per dose:
Parental generation
Control: 33 females, 17 males
7.5% per day: 33 females, 17 males

F1-generation
Control: 14 litters
1% per day: 14 litters
3% per day: 14 litters
7.5% per day: 14 litters
7.5% per day (30 days) and then basic diet (60 days): 14 litters
Basic diet (30 days) and then 7.5% per day (60 days): 14 litters

Importantly, litters were randomly culled on day 4 after birth to four males and four females when possible.
Control animals:
yes, concurrent vehicle
Details on study design:
Male and female rats were placed on the appropriate test diet at 6 weeks of age. Mating was started after 4-5 weeks of test diet feeding. Pups were weaned at 21 days of age and fed the same diet as the parental rats. Parental males were killed at the end of the mating period and female rats were killed after their litters had been weaned. Seven litters from each of groups 1-4 were killed when they were 30 days old to evaluate the dose-response effects of the test chemical. Also at 30 days, the diet for group 5 was changed from 7.5% of the test chemical to control, and the diet for group 6 was changed from control to 7.5% of the test chemical. Seven litters from each of groups 1, 4, 5 and 6 were then killed at 90 days of age to evaluate the reversibility of the effects of the test chemical.

Examinations

Maternal examinations:
Food and water consumption were measured for 1 week prior to mating and for 3 weeks during gestation. Body-weight measurements of parental rats were obtained on the same days as consumption determinations, and detailed physical examinations were performed before mating. The urinary bladder was removed and processed for light microscopy.
Ovaries and uterine content:
No Data Available
Fetal examinations:
Food and water consumption were determined weekly after weaning except during week 5 post-birth when some litters were killed and others had their experimental diets changed. Pups in each litter were weighed as a group by sex after birth, at 4, 7 and 14 days after birth, and then individually at weekly intervals until the time of killing. The health status of the pups was also determined on these days. Blood specimens were collected for haematology. Serum was analyzed for the presence of cholesterol, triglycerides, folate, vitamin A and E, and iron and iron-binding capacity. The adrenals, liver and full and emptied caecum was removed at the time of killing and weighed. Bladders from one male and one female in each litter were examined by light microscopy.
Statistics:
Statistical analyses were performed with a generalized linear model procedure (SAS Institute, Inc., USA). Duncan's multiple range test was used for multiple comparison of means. Comparisons were made between group 1 and each of the other groups and between group 4 and groups 5 and 6.
Indices:
No Data Available
Historical control data:
No Data Available

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

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):
The test chemical treatment causes lower body-weight gains. Significant differences were noted only between the control and the high-dose groups, with the exception of a significant increase in water consumption by the females treated with 1% of the test chemical.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Unchanged basal diet consumption in males were observed. Significant differences were noted only between the control and the high-dose groups, with the exception of a significant increase in water consumption by the females treated with 1% of the test chemical.
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
effects observed, treatment-related
Description (incidence and severity):
The test chemical caused increase in water consumption in females. Significant differences were noted only between the control and the high-dose groups, with the exception of a significant increase in water consumption by the females treated with 1% of the test chemical.
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:
not specified
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
not specified
Histopathological findings: neoplastic:
not specified
Other effects:
not specified
Details on results:
No Data Available

Maternal developmental toxicity

Number of abortions:
not specified
Pre- and post-implantation loss:
not specified
Total litter losses by resorption:
not specified
Early or late resorptions:
not specified
Dead fetuses:
not specified
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:
not specified
Other effects:
not specified

Effect levels (maternal animals)

Dose descriptor:
LOAEL
Effect level:
1 000 other: mg/kgbw/day
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Fetal body weight changes:
effects observed, treatment-related
Description (incidence and severity):
For male and female rats at week 4 post-birth, the values of body weight, food consumption (basal diet) and water consumption decreased with increased test chemical concentrations. Rats treated with 7.5% of the test chemical weighed about 60% as much as control rats, and males fed 3% of the test chemical weighed significantly less (approx. 10%) than controls. Decreases in diet consumption were also observed at 3 and 7.5% dietary test chemical. At week 12 post-birth, body weights of 7.5% of the test chemical-treated males and females remained significantly lower than controls.


Details on embryotoxic / teratogenic effects:

At week 12 post-birth, body weights of 7.5% NaS-treated males and females remained significantly lower than controls. All male rats fed NaS, including those switched from NaS to control diet, and consumed significantly less diet than controls during wk 6-12 post-birth. Female rats in all NaS-treated groups consumed similar amounts of diet as did controls. Water consumption during week 6-12 post birth was significantly greater, compared with controls in groups 4 (7.5% NaS) and 6 (control switched to 7.5% NaS).




Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not specified
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): For male and female rats at week 4 post-birth, the values of body weight, food consumption (basal diet) and water consumption decreased with increased test chemical concentrations. Rats treated with 7.5% of the test chemical weighed about 60% as much as control rats, and males fed 3% of the test chemical weighed significantly less (approx. 10%) than controls. Decreases in diet consumption were also observed at 3 and 7.5% dietary test chemical. At week 12 post-birth, body weights of 7.5% of the test chemical treated males and females remained significantly lower than controls.
Reduction in number of live offspring:
not specified
Changes in sex ratio:
not specified
Changes in litter size and weights:
not specified
Changes in postnatal survival:
not specified
External malformations:
not specified
Skeletal malformations:
not specified
Visceral malformations:
effects observed, treatment-related
Description (incidence and severity):
At 30 days post-birth, a decrease in both absolute and relative liver weights related to the dose of the test chemical was observed. Male rats switched from test chemical to control diet also had lower absolute liver weights than control rats. For female rats liver weights were lower than those of controls when fed 7.5% test chemical diet throughout the study. For those switched from the control to test chemical diet, there were no differences at 30 days in the absolute weight of the empty caecum. Animals exposed to 7.5% test chemical were anemic at 30 days post-birth, as indicated by the decrease in red blood cells (RBC), hemoglobin (Hgb) and haematocrit (HCT). Mean values for mean corpuscular volume, hemoglobin and hemoglobin concentration were consistent with a diagnosis of iron deficiency. Rats of both sexes fed 3% test chemical had significantly decreased Hgb and HCT. In addition, no difference was observed in hematological parameters between the group switched from the 7.5% test chemical to control diet at 30 days post-birth and the control group. Compared with the control group, serum cholesterol, triglycerides and vitamin E were increased and serum vitamin A and folate were decreased in both males and females. t 90 days post-birth, males on the 7.5% test chemical diet had lower absolute and relative liver weights than controls. All animals exposed to 7.5% test chemical had increased caecal weights compared with controls. At 90 days post-birth, the values of haemoglobin (Hgb) and haematocrit (HCT) in rats exposed to 7.5% test chemical throughout the study were still significantly below control values .The effects in the female rats were similar to those in the males. With continuous test chemical treatment serum triglyceride levels in males and females, and serum cholesterol levels in males, were lower than in control. Serum folate was similar to control animals, except in two groups 7.5% test chemical switched to control and control switched to 7.5% test chemical) which showed elevated and reduced values. Serum vitamin A remained significantly depressed in all male groups treated with 7.5% test chemical. The microscopic effects of test chemical treatment on the bladder were negligible. Simple hyperplasia was noted in the bladders of some 7.5 % test chemical-treated rats at 90 days. Morphological changes in the urothelium were also observed by SEM in these groups, but the severity and incidence were low.
Other effects:
not specified

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Body-weight gain, food consumption water consumption, Hematological parameters, serum Lipid and vitamin concentration,

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
LOAEL for the parental generation was considered to be 1% of the test chemical per day and the NOEAL for the F1 generation was considered to be 1% of the test chemical per day.
Executive summary:

In a one-generation study, dose response changes associated with the test chemical treatment was evaluated in Sprague-Dawley rats at 30 and 90 days post-birth. The test chemical in the dietary levels of 0, 1, 3 or 7.5% was administered to rats by feed. Body weights in the parental generation and in the offspring decreased with increased test chemical concentrations. Serum vitamin E, cholesterol and triglyceride concentrations were decreased at 1% and 3% test chemical per day but were significantly increased with 7.5% of the test chemical. The increases in lipids and vitamin E were reversible. The reversibility of the effects of 7.5% of the test chemical was examined in 90-day-old rats. Although values for haematological parameters and serum vitamin A remained significantly reduced at 90 days, however, changes were less severe than at 30 days. Histological examinations revealed that the effects of 7.5% of dietary test chemical on the bladder were negligible, indicating that the physiological changes observed in the young rat are probably not directly related to the production of bladder tumors. Therefore, the NOEAL for the offspring was considered to be 1% of the test chemical per day and the LOAEL in the parental generation was considered to be 1% of the tet chemical per day.