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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1992-02-14 - 1992-05-19
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP and guideline compliant study with read-across substance.

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 476 (In Vitro Mammalian Cell Gene Mutation Test)
Version / remarks:
adopted April 4, 1984
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: liquid

Method

Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction from Aroclor 1254 induced (i.p.) rat liver
Test concentrations with justification for top dose:
without S9 mix: for both experiments: 500, 250, 125, 62.5 and 31.25 µg/mL
with S9 mix:
first experiment: 1000, 500, 250, 125 and 62.5 µg/mL
second experiment: 2000, 1500, 1000, 500 and 250 µg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: dimethylsulfoxide
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with S9 mix
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-methyl-N-nitro-N-nitrosoguanidine
Remarks:
without S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 24 hours
- Exposure duration: 3 hours
- Expression time (cells in growth medium): 7 days
- Fixation time (start of exposure up to fixation or harvest of cells): not indicated

STAIN: was performed with Giemsa

NUMBER OF REPLICATIONS: all controls and treatment levels were run in duplicate.

NUMBER OF CELLS EVALUATED:

DETERMINATION OF CYTOTOXICITY
- Method: cloning efficiency
Evaluation criteria:
The following criteria are used to aid the Study Director to interpret the data, the biological significance of this test system and our historical data being taken into consideration for the final data assessment:
- a test substance is considered as non-mutagenic if it does not induce a mutation frequency that is at least 3 times higher than the mutation frequency of the negative and/or solvent controls;
- a test substance is considered as mutagenic if it induces a 3-fold increase in the mutation frequency when compared to the mutation frequency of the negative and/or solvent controls. In this case, a dose relationship is investigated and considered as significant if p < 0.05.
- the results are considered as ambigous if a large difference is obtained between the two tests.
Acceptance criteria:
The following criteria were considered for acceptability of each test of this study:
- the absolute cloning efficiency of the negative control should not be less than 50 %,
- the mutation frequency of the negative and/or solvent controls should fall within the range of 0 - 20 x 10-6
- the mutation frequency of the positive controls should be higher than the spontaneous one.
Statistics:
Not relevant

Results and discussion

Test results
Species / strain:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
> 1000 µg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: The values of the spontaneous mutation frequencies (negative and solvent controls) with and without S9 mix were in the range of the mean values usually obtained at the laboratory.

ADDITIONAL INFORMATION ON CYTOTOXICITY: The 6 concentrations used for the cytotoxicity test were: 5000, 3000, 1000, 300, 100 and 30 µg/mL with and without metabolic activation system. The absolute cloning efficiency was nul at 3000 and 5000 µg/mL both with and without S9 mix, and decreased, without S9 mix only, by 90 % at 1000 µg/mL and by 30 % at 300 µg/mL. Based upon these results, the test substance showed some signs of cytotoxicity (decrease in the cloning efficiency and/or dead cells) for the V79 cells at the concentrations > 1000 µg/mL, both with and without S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion