dichloromethane; methylene chloride

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Klimisch code: 1. Reliable without restrictions. “Key study” Well-defined, GLP compliant study

Data source

Reference

Reference Type:

publication

Title:

Methylene Chloride: Two-Generation Inhalation Reproductive Study in Rats.

Author:

Nitschke et al

Year:

1988

Bibliographic source:

Fundamental and Applied Toxicology, Vol. 11: 60-67.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Principles of method if other than guideline:

test method EU B.35

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Methylene chloride

IUPAC Name:

Methylene chloride

Test material form:

other: vapour

Details on test material:

Methylene chloride (99.86% pure)

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles River Breeding Laboratory, Kingston, NY
- Age at study initiation: 7 weeks
- Weight at study initiation: (P) Males: x-x g; Females: x-x g; (F1) Males: x-x g; Females: x-x g
- Fasting period before study:
- Housing: singly in wire-mesh stainless steel cages
- Use of restrainers for preventing ingestion (if dermal): yes/no
- Diet (e.g. ad libitum):ad libitum, except for during exposure
- Water (e.g. ad libitum):ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°F):72
- Humidity (%): 40 -60
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light):12 hour

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Details on exposure:

Whole body inhalation chamber exposure to test substance vapour.
Exposure chambers: 14.5 m3 chambers with stainless steel pyramidal-shaped ceilings with resin-coated floors and walls.

Details on mating procedure:

F0: after 14-week exposure; F1: after 17-week exposure
Breeding programme: two 5-day cohabitation periods
M/F ratios per cage: 1M/1F;
F1: avoided breeding of females and males from the same litter.

Duration of treatment / exposure:

For 14 weeks (F0 rats); for 17 weeks (F1 rats).
Dams were not exposed from gestation Day 21 until postpartum Day 4.

Frequency of treatment:

6 h/day, 5 days/week –premating period
6 h/day, 7 days/week –mating, gestation and lactation.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 500, or 1500 ppm
Basis:

No. of animals per sex per dose:

F0 and F1: 30 male and 30 female rats per group/per dose.

Control animals:

yes

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes / Daily observation for signs of toxicity and changes in demeanour.
- Time schedule:
- Cage side observations checked in table [No.?] were included.

body weights measured prior to exposure start and weekly thereafter prior to mating; then after mating females – bodyweights measured on gestation Days 0, 7, 14 & 21; males - bodyweights measured weekly.

Litter observations:

Offspring: sex, body weights, number of live pups (on Days 1, 4, 7, 14, 21, & 28 after delivery.

F1 (10/sex/dose group) and F2 (30/sex/dose group): complete necropsy examination. Complete histopathology performed on F1 and F2 of control and high dose group.

Postmortem examinations (parental animals):

F0 and F1: gross necropsy of organs and tissues, histopathology was not performed.

Statistics:

Bartlett’s test, ANOVA, Dunnett’s test, Wilcoxon’s rank sum test with Bonferroni’s correction (for body weights), Fisher exact probability test (for fertility indices), binominal distribution test (for neonatal sex ratio).

Results and discussion

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

NOAEC parental toxicity:

1500 ppm

NOAEC developmental & reproduction toxicity:

1500 ppm

F0 Generation:

Mortality:

No treatment-related mortality or signs of toxicity were observed.

Body weight:

No treatment-related significant reductions in body weights were observed.

 

Fertility and gestation:

No treatment related changes in survival, letter size and pup weights were observed.

 

Necropsy & Gross examination:

No treatment-related lesions were observed.

 

F1 Generation:

Mortality:

No treatment-related mortality or signs of toxicity were observed.

Body weight:

No treatment-related significant reductions in body weights were observed.

 

Fertility and gestation:

No treatment related changes in survival, letter size and pup weights were observed.

 

Necropsy & Gross examination:

No treatment-related lesions were observed.

 

Histopathologic examination:

No treatment-related histopathologic changes were observed.

Applicant's summary and conclusion

Conclusions:

Under the study conditions, a level of 1500 ppm methylene chloride vapour is considered as a no observed adverse effect concentration (NOAEC) for both parental and developmental/ reproductive toxicity in Fischer 344 rats.