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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:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and OECD testing guideline compliant study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Substance type: pigment
- Physical state: solid
- Analytical purity: 99-99.5 %
- Stability under test conditions: yes
- Storage condition of test material: room temperature
- stability in solvent: 48 hours in H20, polyethylene glycol, CMC, at least 96 hours in DMSO/methanol (15:85); at least 24 h in DMSO/ethanol

Method

Target gene:
not applicable
Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254-induced rat liver S9 mix
Test concentrations with justification for top dose:
with and without S9 mix:
18 h: 0.3; 1.0; 3.0; 6.0; 10.0; 15.0; 20.0 microgramm/ml
28 h: 3.0; 6.0; 10.0; 15.0; 20.0 microgramm/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s): DMSO/Ethanol (15:85)
- Justification for choice of solvent/vehicle: The solvent was chosen according to its solubility properties and its nontoxcicity for the cells. The final concentration of the solvent in the culture medium did not exceed 1 % v/v.
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
ith metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 48 h (28 h preparation interval) and 55 h (18 h preparation interval)
- Exposure duration: 4h
- Expression time (cells in growth medium): 28h and 18h

SELECTION AGENT (mutation assays):
SPINDLE INHIBITOR (cytogenetic assays): colcemid
STAIN (for cytogenetic assays): Giemsa

NUMBER OF REPLICATIONS: 2

NUMBER OF CELLS EVALUATED: At least 100 weIl spread metaphases per culture were scored for cytogenetic damage on coded slides except for the
positive control cultures where 25 metaphases were scored.

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index

OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Determination of endoreplication: no
-

OTHER: Only metaphases with characteristic chromosome numbers of 22 ± 1 were included in the analysis.
Evaluation criteria:
Acceptance criteria:
a) the number of aberrations found in the controls fall within the laboratory range: 0.00 % - 4.00 %.
b) the positive control substances should increases in the number of cells with aberrations.

A test article is classified as mutagenic if it induces either a concentration-related increase in the number of structural chromosomal aberrations or a significant positive response for at least one of the test points.
Statistics:
Chi-square test

Results and discussion

Test results
Species / strain:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
In the absence of S9, with 20.0 mg/L strong precipitation of the test article prevented the cytogenetic evaluation. In th e presence of S9, in the
cultures treated with 15.0 and 20.0 mg/L strong precipitation of the test article prevented the evaluation.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative