1,3-bis(3-methyl-2,5-dioxo-1H-pyrrolinylmethyl)benzene

Genetic toxicity: in vivo

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:

June-July 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well conducted study according to GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

Batch no: BOM pp2
Purity: 87 ± 3% (m/M); see CoA attacahed
Other: m-Xylylene bis (itaconimide): 2-5%

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Duration of treatment / exposure:

single application

Frequency of treatment:

single application

Post exposure period:

24, 48 and 72 h after treatment

No. of animals per sex per dose:

Range finding: 750, 1500, 3000 and 5000 mg/kg bw

Main study: 5 mice sex/group
0 mg/kg (vehicle control); Sacrifice time: 24, 48, 72 hours
750 mg/kg; Sacrifice time: 24 hours
1500 mg/kg; Sacrifice time: 24 hours
2500 mg/kg; Sacrifice time: 24, 48, 72 hours
3000 mg/kg; Sacrifice time: 24, 48, 72 hours

Control animals:

yes, concurrent vehicle

Positive control(s):

30 mg/kg chlorambucil

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

see below

Vehicle controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

One male animal treated with BCI-MX at 3000 mg/kg was killed in extremis approximately 2 hours after dosing as a result of hunched posture, piloerection, inactivity and slow respiration. Another male animal dosed with BCI-MX at 2500 mg/kg was found dead approximately 4 hours after dosing, having previously showed signs of hunched posture and inactivity. All other animals survived to scheduled termination, although some animals dosed at 1500, 2500 and 3000 mg/kg showed intermittent signs throughout the study, inclUding hunched posture, piloerection, ungroomed fur at the base of the tail, reduced activity, and redness and swelling in the anal region.

Bone marrow smears on glass slides were made from each animal; these were stained and prepared for examination. As all but one animal dosed at 3000 mg/kg survived to scheduled termination, slides from animals dosed at 2500 mg/kg were not analysed. A total of at least 2000 erythrocytes per animal was then examined for the presence of micronuclei, using the light microscope. Calculated values of micronuclei per 1000 polychromatic erythrocytes were analysed statistically using the Mann-Whitney U test. The ratio of polychromatic: mature cells was also calculated for each sex and group, as an indicator of gross toxicity.

There was some evidence of bone marrow toxicity, as evidenced by depression of bone marrow proliferation, on slides prepared from animals dosed with BCI-MX at 3000 mg/kg and sacrificed 48 or 72 hours later. Frequencies of micronucleated polychromatic erythrocytes in animals killed 24, 48 or 72 hours after administration of BCI-MX were similar to those in concurrent controls. This lack of treatment-related effect was apparent in both sexes, and was confirmed by statistical analysis. Statistically significant increases over controls were, however, seen in positive control group animals given chlorambucil at 30 mg/kg (p<0.01). It is concluded that, under the conditions of test, there was no evidence of induced chromosomal or other damage leading to micronucleus formation in polychromatic erythrocytes of treated mice 24, 48 or 72 hours after oral administration of BCI-MX. The test procedure was highly sensitive to the chromosome-damaging action of chlorambucil.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative