(3aα,4β,7β,7aα)-octahydro-4,7-methano-1H-indene

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not reported.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1983

Reference 2

Reference Type:

review article or handbook

Title:

Unnamed

Year:

1985

Report date:

1985

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Evaluation of the effect of the test material on the development of embryonic rats.
- Short description of test conditions: Mated female rats received test material by gavage at the dose levels of 0, 250, 500, or 1000 mg/kg bw/day on days 6 through 15 of gestation. The test material was diluted with corn oil and controls received an equivalent volume of corn oil (2.0 ml/kg bw/day).
- Parameters analysed / observed: All animals were weighed and observed daily for clinical signs. The animals were sacrificed at gestational day 20 (gd20) and the fetuses were delivered by caesarean section. The number and placement of fetuses and resorption sites were recorded. Fetuses were removed, weighed, sexed, and examined for external, soft tissue and skeletal abnormalities.

GLP compliance:

no

Remarks:

Pre-GLP

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(3aα,4β,7β,7aα)-octahydro-4,7-methano-1H-indene

EC Number:

220-585-8

EC Name:

(3aα,4β,7β,7aα)-octahydro-4,7-methano-1H-indene

Cas Number:

2825-82-3

Molecular formula:

C10H16

IUPAC Name:

(1R,2S,6R,7S)-tricyclo[5.2.1.0^{2,6}]decane

Test material form:

liquid

Test animals

Species:

rat

Strain:

Fischer 344

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: not reported
- Weight at study initiation: approx. 172, 175, 173 and 174 g for groups exposed to 0, 250, 500 and 1000 mg/kg bw/d, respectively.
- Fasting period before study: not reported
- Housing: plastic cages containing wood chip bedding
- Diet (e.g. ad libitum): Ralston Purina Co. ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 72-76 °F
- Humidity (%): not reported
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12h / 12h

IN-LIFE DATES: not reported

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

VEHICLE
- Justification for use and choice of vehicle (if other than water): not reported
- Concentration in vehicle: not reported
- Amount of vehicle (if gavage): Total volume: 2 mL/kg bw/d
- Lot/batch no. (if required): not reported
- Purity: not reported

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused: The females were placed with fertile males of the same stock overnight and checked for presence of sperm by vaginal wash the next morning.
- Proof of pregnancy: The day on which sperm was found was designated day 0 of pregnancy.

Duration of treatment / exposure:

by gavage on days 6 through 15 of gestation.

Frequency of treatment:

daily from gd 6 to gd15

Duration of test:

until gd 20

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Group 1 (Control)

Doses / concentrations 2

Dose / conc.:

250 mg/kg bw/day (nominal)

Remarks:

Group 2 (Low dose)

Doses / concentrations 3

Dose / conc.:

500 mg/kg bw/day (nominal)

Remarks:

Group 2 (Mid dose)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Remarks:

Group 4 (High dose)

No. of animals per sex per dose:

Not reported

Control animals:

yes, concurrent vehicle

Details on study design:

No data

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: daily

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #20
- Organs examined: No data

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data

Statistics:

Measured data were analyzed for statistical significance by the Student's t method and are listed as mean +/- standard deviation (S.D.).
Incidence data were analyzed with Fisher's exact test.
The level of significance chosen for all tests was p < 0.05.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Many animals in the 1000 mg/kg bw/d group exhibited tremors and a few also had mild convulsions.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Treated rats gained less weight than the controls during the treatment period.
The decreased weight gain was dose related with both the 1000 mg/kg and 500 mg/kg orally dosed groups.
The 1000 mg/kg bw/d group also gained significantly less weight during the latter phase of treatment.
The values for total weight gained during gestation and also maternal weight gain (gd20 weight with gravid uterus removed - gd0 weight) were also significantly reduced in the 1000 mg/kg bw/d group.
The weight gain following cessation of treatment was not signficantly different from the control for any group.

Maternal developmental toxicity

Early or late resorptions:

effects observed, treatment-related

Description (incidence and severity):

There was a statistically significant increase in litters containing resorptions amounting to 25 percent or more of the implants in the high dose group; however, the incidence of resorptions / litter although elevated was not significant.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: tremors and mild convulsions at 1000 mg/kg bw/day

Results (fetuses)

Fetal body weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

The 500 mg/kg bw/d dosed group had a significantly reduced fetal weight while the 1000 mg/kg bw/d group did not.

Reduction in number of live offspring:

effects observed, non-treatment-related

Description (incidence and severity):

There were an increase in embryolethality in the 1000 mg/kg bw/d group but this is probably due to a maternal toxicity (secondary effect).

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

The incidence of malformation was not significantly elevated for any treatment group.
The most common major malformation observed in the 2 higher dosed groups was nanoidism. This abnormality did not occur in the control or lowest dose group in this study but has occured in other control litters historically in this laboratory at a rate similar to that observed in the higher treatment group.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

The second most common major malformation involved the urinary tract development. The malformation included hydro-nephrosis, dilated ureter, and agenesis of the bladder. It occured in 3 fetuses from 1 litter. Since the substance was observed in the fetuses from only one litter it probably arose spontaneously rather than as a result of the test material treatment. Thus, the incidence of this major malformations at the higher dose does not appear significant.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

not specified

Basis for effect level:

other: effects are due to maternal toxicity at 1000 mg/kg bw/day (increase in embryolethality) and at 500 mg/kg bw/day (decrease in fetal weight)

Overall developmental toxicity

Key result

Developmental effects observed:

no

Applicant's summary and conclusion

Conclusions:

Under the test conditions, the NOAEL for maternal toxicity is 500 mg/kg bw/day and the NOAEL for developmental toxicity is 1000 mg/kg bw/day in rats.

Executive summary:

In a pre-natal developmental toxicity study, test substance was administered by oral route (gavage) to groups of mated female rats at the dose levels of 0, 250, 500, or 1000 mg/kg bw/day on days 6 through 15 of gestation. The test material was diluted with corn oil and controls received an equivalent volume of corn oil (2.0 ml/kg bw/day). All animals were weighed and observed daily for clinical signs. The animals were sacrificed at gestational day 20 (gd20) and the fetuses were delivered by caesarean section.

The number and placement of fetuses and resorption sites were recorded. Fetuses were removed, weighed, sexed, and examined for external, soft tissue and skeletal abnormalities.

There was a decreased weight gain in the two higher dose groups and tremors and mild convulsions were observed in the top dose group.

Data concerning nonteratogenic embryotoxicity were ambigous.

There were an increase in embryolethality in the 1000 mg/kg bw/d group and a decrease in fetal weight in the 500 mg/kg bw/d group. These indicators of embryotoxicity were not distributed in a dose-related manner. Most likely they were secondary to maternal toxicity (reduced weight gains, tremors, and convulsions) in the high dosed groups.

Under the test conditions, the NOAEL for maternal toxicity is 500 mg/kg bw/day and the NOAEL for developmental toxicity is 1000 mg/kg bw/day in rats.