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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 from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: acceptable documented publication

Data source

Reference
Reference Type:
publication
Title:
In vitro induction of polyploidy and chromatid exchanges by culture medium extracts of natural rubbers compounded with 2-mrcaptobenzothiazole as a positve control candidate for genotoxicity tests
Author:
Matsuoka, A.; et al.
Year:
2005
Bibliographic source:
J. Biomed. Mater. Res. 75A, 439-444

Materials and methods

Principles of method if other than guideline:
in vitro chromosome aberration assay
GLP compliance:
not specified
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Constituent 1
Chemical structure
Reference substance name:
Benzothiazole-2-thiol
EC Number:
205-736-8
EC Name:
Benzothiazole-2-thiol
Cas Number:
149-30-4
Molecular formula:
C7H5NS2
IUPAC Name:
1,3-benzothiazole-2-thiol
Details on test material:
MBT

Method

Target gene:
chromosome aberration and endoreduplication
Species / strain
Species / strain / cell type:
mammalian cell line, other: CHL cells
Metabolic activation:
with and without
Metabolic activation system:
S9-mix
Test concentrations with justification for top dose:
-S9: 0, 0.2, 0.4 µg/ml, +S9: 0, 0.2, 0.4, 0.6 µg/ml
Controls
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: additional substances tested, like extracts from rubber sheets, which induced significant increase in abberant cells compared to solvent control

Results and discussion

Test results
Species / strain:
mammalian cell line, other: CHL cells
Metabolic activation:
with and without
Genotoxicity:
other: chromosome aberration: -S9 negative, +S9 inconclusive; increase in polyploid cells and endoreduplications
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
other: number of aberrant cells increased after treatment with rubber extracts
Remarks on result:
other: strain/cell type: CHL cells
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

In the CA test performed with CHL cells, MBT induced polyploidy, including endoreduplication, in the absence and presence of S9 mix. Frequency of polyploid cells and endoreduplications was 3.6% and 6.2% without S9 mix and 2 % and 0.4 % with S9 mix at 0.2 mg/ml. No endoreduplications were noted in the solvent control.

MBT showed inconclusive response in structural CA induction at 0.4 mg/ml with S9 mix.

Applicant's summary and conclusion