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Toxicological information

Genetic toxicity: in vivo

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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
Study period:
year of publication: 1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well performed and documented literature data

Data source

Reference
Reference Type:
publication
Title:
Quantitative and qualitative studies of micronucleus induction in mouse erythrocytes using flow cytometry. I. Measurement of micronucleus induction in peripheral blood polychromatic erythrocytes by chemicals with known and suspected genotoxicity.
Author:
Grawé J, Nuesse M, Adler I-D
Year:
1997
Bibliographic source:
Mutagenesis 12: 1-8

Materials and methods

Principles of method if other than guideline:
in vivo micronucleus assay
GLP compliance:
not specified
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): 2-chlorobenzylidene malonitrile (CS)

Test animals

Species:
mouse
Strain:
other: (102/E1xC3H/E1)F1
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: GSF-Forschungszentrum für Umwelt und Gesundheit
- Age at study initiation: 10-12 weeks
- Weight at study initiation: about 28 g
- Diet: ad libitum
- Water: ad libitum

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- vehicle: dimethyl sulphoxide (DMSO)
Details on exposure:
injected volumes: 5 µl/g bw
Duration of treatment / exposure:
single exposure
Frequency of treatment:
single exposure
Post exposure period:
72 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
10, 20, 40 mg/kg
Basis:
nominal conc.
No. of animals per sex per dose:
3 males per dose group
Control animals:
no

Examinations

Tissues and cell types examined:
-polychromatic erythrocytes from the peripheral blood
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
based on an LD50 value of about 60 mg/kg

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
- Blood samples from the same animals were collected at 0, 24, 40, 48, and 72 hours by retroorbital bleeding under ether anaesthesia (about 100 µl per animal per sampling time).

DETAILS OF SLIDE PREPARATION:


METHOD OF ANALYSIS:


OTHER:
Statistics:
For comparisons between groups a one-tailed Students's t-test was used. Significance values were divided by the number of comparisons made for each treatment group in order to compensate for multiple comparisons.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Additional information on results:
Animals at the mid and high dose became moribund. One animal of the high dose (40 mg/kg bw) died 20h after treatment. MPCE frequencies were not elevated and the PCE/NCE ratios were not depressed.

Any other information on results incl. tables

 sampling time (h)     10 mg/kg     20 mg/kg     40 mg/kg
   MPCE mean (SD)  PCE %  MPCE mean (SD)  PCE %  MPCE mean (SD)  PCE
 0.0016 (0.0002)  2.1  0.0016 (0.0002)  2.0  0.0018 (0.0001)  3.0
 24  0.0018 (0.0004)  2.5  0.0018 (0.0002)  2.5  0.0015 (0.0000)  2.9
 48  0.0017 (0.0003)  2.6  0.0017 (0.0006)  2.6  0.0014 (0.0001)  2.8
 72  0.0018 (0.0003)  2.3  0.0019 (0.0002)  2.3  0.0015 (0.0001)  *

* nonreadable in the publication

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
CS did not induce micronuclei in vivo under the current test conditions.
Executive summary:

Mice were treated with single intraperitoneally doses of 10, 20, or 40 mg/kg bw CS. No induction of micronuclei in vivo was observed, even in the lethal concentration range.

The study has been judged to be reliable with restriction (RL2) due to some shortcomings, e.g. missing data on substance purity, housing conditions. The study was selected as key study.