Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: OECD guideline and GLP. There are some minor deviations which do not affect the outcome of the study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Remarks:
(only onde dose level was used and only 1000 erythrocytes were counted per animal instead of 2000).
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): monochloressigsäuremethylester
- Physical state: clear, colourless liquid
- Analytical purity: 99.4%
- Lot/batch No.: Tank from January 25th, 1988
- Storage condition of test material: dark at 4 ºC

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hoechst AG, Kastetngrund, SPF breeding colony
- Age at study initiation: 7 weeks
- Weight at study initiation: males: 26-33 g; females: 21-27 g
- Housing: in fully air-conditioned rooms in Macrolon cages (type 3), on softwood granulate in groups of five animals
- Diet (e.g. ad libitum): rat/mice diet Altromin 1324 (Altromin-GmbH, Lage/Lippe), ad libitum
- Water (e.g. ad libitum): tap water in plastic bottles, ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2 ºC
- Humidity (%): 55 ± 10%
- Photoperiod (hrs dark / hrs light): 12 hours light daily

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: sesame oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: The test compound dilutions were prepared fresh each day. 750 mg of the test substance were weight in a beaker, mixed with sesame oil, washed out in a 25 ml flask and topped up to the calibration mark.
Duration of treatment / exposure:
Animals were treated with the test substance once and the animals were killed at 24, 48 and or 72 hours after treatment.
Frequency of treatment:
Single dose
Post exposure period:
Animals were killed at 24, 48 and or 72 hours after treatment.
Doses / concentrations
Remarks:
Doses / Concentrations:
300 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
5 animals per sex per dose
Control animals:
yes
Positive control(s):
- Cyclophosphamid (Endoxan)
- Route of administration: orally
- Doses / concentrations: 50 mg/kg bw

Examinations

Tissues and cell types examined:
1000 polychromatic erythrocytes were counted for each animal. The number of cells with micronuclei was recorded, not the number of individual micronuclei. The ratio of polychromatic to normochromatic erythrocytes was determined.
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: The dose levels were selected on the basis of a preliminary study to determine the acute toxicity and the maximal applicable dose. Oral administration of 400 mg/kg bw caused partial lethality in male and female mice. The highest sublethal dose of 300 mg/kg bw was selected.

DETAILS OF SLIDE PREPARATION: Staining procedure:
5 minutes in methanol
3 minutes in May-Grünwalds solution
2 minutes in May-Grünwalds solution diluted 1:1 with distilled water
brief rinsing twice in distilled water
10 minutes staining in 1 part Giemsa solution to 6 parts buffer solution
rinsing with distilled water
drying
coating with Entellan
Evaluation criteria:
All statistical results are based on a 95% level of significance.
Statistics:
Comparision of dose groups with the simultaneous control group was performed according to Wilcoxon (paired, one-sided, increase).

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Remarks:
(death of 4 males and 2 females out of 70 animals. These animals were replaced).
Negative controls valid:
yes
Positive controls valid:
yes

Any other information on results incl. tables

The incidence of micronucleated polychromatic erythrocytes in the dose groups was within the normal range of the negative control groups. Only in two cases (females of the 24 and 48 hours killing time) there was a significant increase of micronucleated polychromatic erythrocytes but which lies not outside the normal range and was of no toxicological relevance. The number of normochromatic erythrocytes containing micronuclei was not increased. The ratio of polychromatic/normochromatic erythrocytes in both male and female animals remained unaffected by the treatment.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
It can be stated that, under the conditions described, administration of Monochloressigsäuremethylester did not lead to a substantial increase of micronucleated polychromatic erythrocytes. It is concluded that the test substance is not mutagenic in the micronucleus test.
Executive summary:

Methyl chloroacetate was tested in the micronucleus test. The test substance was administered orally by gavage to male and female NMRI mice at a dose of 300 mg/kg bw. The animals were treated once and killed at 24, 48 or 72 hours after treatment. The incidence of micronucleated polychromatic erythrocytes in the treated animals was within the normal range of the negative control. The number of normochromatic erythrocytes containing micronuclei was not increased. The ratio of polychromatic/normochromatic erythrocytes in both male and female animals remained unaffected by the treatment. It can be stated that, under the conditions described, administration of Monochloressigsäuremethylester did not lead to a substantial increase of micronucleated polychromatic erythrocytes. It is concluded that the test substance is not mutagenic in the micronucleus test.