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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: acceptable well-documented publication which meets basic scientific principles
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
In vitro genotoxicity testing of (1-chloroethenyl)oxirane, a metabolite of ß-chloroprene
Author:
Himmelstein MW, Gladnick NL, Donner EM, Snyder RD, Valentine R.
Year:
2001
Bibliographic source:
Chemico-Biological Interactions 135-136: 701-713

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Principles of method if other than guideline:
The methods of Fenech & Morley (1985), Fenech (2000) and Kalweit et al (1999) were followed, and were broadly comparable to the guideline.
GLP compliance:
not specified
Remarks:
published study
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Chloroprene monoepoxide (CEO); (1-chloroethenyl)oxirane, is the main metabolite produced by in vitro metabolism of chloroprene. The test material had a purity of >98%, was synthesised (methods published in Himmelstein et al (2001) Chemico-Biological Interactions 135-136: 267-284), and was stored frozen with nitrogen in the vial headspace.

Method

Target gene:
Not applicable - chromosome aberration study.
Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
without
Test concentrations with justification for top dose:
0 to 0.943 mM, the upper concentrations corresponded to those below which cytotoxicity was observed.
Vehicle / solvent:
1% DMSO
Controls
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
no
Details on test system and experimental conditions:
Chinese hamster V79 cells were seeded onto 4-well tissue culture slides at ca. 2000 - 5000 cells/well, covered, and allowed to grow at 37°C in an humidified atmosphere of 5% CO2 for 24 h. The covers of the well slides were removed and the slides were placed into sterile bottles filled to the rim with complete culture media (Eagle's minimum essential medium with 10% fetal bovine serum) without S9 mix. The test substance was diluted in DMSO and injected into the bottles with a syringe followed by gentle mixing.
The cells were exposed for 3 h then removed from the exposure bottles. The covers were replaced, and fresh medium containing cytochalasin B was added. The cells were cultured for an additional 16 h. After the incubation, the cells were treated with hyptonic solution and stained wth Dif-Qwik in situ on the slides. A minimum of 500 binucleated cells were scored for micronuclei, and assessed for the proportion of binucleated cells and mononucleated cells.
Cytotoxicity was determined by comparing the number of binucleated cells in treated groups to the control, and assessing cell morphology.
Evaluation criteria:
For a chemical to be classified as positive, a concentration-dependent increase in the frequency of micronucleated binucleated cells was required, with at least one concentration producing approximately a three-fold or higher MN frequency than that observed in the vehicle control.
Statistics:
Not required.

Results and discussion

Test results
Species / strain:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Additional information on results:
No precipitation was observed. Cytotoxicity, observed as a reduced proportion of binucleated cells and altered cell morphology was observed at test concentrations of 0.175 mM and above.
The MN frequency of the vehicle controls was 0.9±0.6% (1 SD for 6 determinations).
Concentrations analysed for aberrations were between 0.02 and 0.2 mM. There was no evidence of mutagenicity.
Remarks on result:
other: strain/cell type: V79
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

The use of positive controls was not reported, however 3,4-epoxy-1-butene and 1,2:3,4-diepoxybutane were also evaluated and found to be clearly clastogenic.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative without metabolic activation

Chloroprene monoepoxide (CEO), an in vitro metabolite of chloroprene, was found to be non-clastogenic to Chinese hamster V79 cells in vitro.
Executive summary:

Chloroprene monoepoxide (CEO), an in vitro metabolite of chloroprene, was found to be non-clastogenic to Chinese hamster V79 cells when tested up to concentrations of 0.2 mM in vitro.