Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
other: in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbital/p-Naphthoflavone induced rat liver S9 mix
Test concentrations with justification for top dose:
Concentration range in Experiment I (without metabolic activation, 4 h exposure period, 14 h recovery time, 18 h preperation interval): 3.1, 6.3 and 12.5 µg/mLConcentration range in Experiment I (with metabolic activation, 4 h exposure period, 14 h recovery time, 18 h preperation interval): 12.5, 25 and 50 µg/mLConcentration range in Experiment II (without metabolic activation, 18 h exposure period, 0 h recovery time, 18 h preperation interval): 3.1, 6.3 and 12.5 µg/mLConcentration range in Experiment II (without metabolic activation, 28 h exposure period, o h recovery time, 28 h preperation interval): 6.3 and 12.5 µg/mLConcentration range in Experiment II (with metabolic activation, 4 h exposure period, 24 h recovery time, 28 h preperation interval): 12.5, 25 and 50 µg/mL
Vehicle / solvent:
Tetrahydrofuran (THF)
Controls
Untreated negative controls:
yes
Remarks:
culture medium
Negative solvent / vehicle controls:
yes
Remarks:
THF
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
ethylmethanesulphonate
Details on test system and experimental conditions:
METHOD OF APPLICATION: in mediumSTAIN (for cytogenetic assays): with GiemsaNUMBER OF REPLICATIONS: two independent experimentsNUMBER OF CELLS EVALUATED: per culture 100 metaphase plates
Evaluation criteria:
Acceptability of the Test:The chromosome aberration test performed is considered acceptable if it meets the following criteria:a) The number of structural aberrations found in the negative and/or solvent controls falls within the range of historical laboratory control data: 0.0 - 4.0 %.b) The positive control substances should produce significant increases in the number of cells with structural chromosome aberrations, which are within the range of the laboratories historical control data.Evaluation of Results:A test item is classified as non-clastogenic if:- the number of induced structural chromosome aberrations in all evaluated dose groups is in the range of historical control data (0.0 - 4.0 % aberrant cells exclusive gaps) and/or- no significant increase of the number of structural chromosome aberrations is observed.A test item is classified as clastogenic if:- the number of induced structural chromosome aberrations is not in the range of our historical control data (0.0 - 4.0 % aberrant cells exclusive gaps) and- either a concentration-related or a significant increase of the number of structural chromosome aberrations is observed.Although the inclusion of the structural chromosome aberrations is the purpose of this study, it is important to include the polyploids and endoreduplications. The following criteria is valid:A test item can be classified as aneugenic if:- the number of induced numerical aberrations is not in the range of our historical control data (0.0 - 8.5 % polyploid cells).
Statistics:
Statistical significance was confirmed by means of the Fisher's exact test (p < 0.05). However, both biological and statistical significance are considered together. If the criteria mentioned above for the test item are not clearly met, the classification with regard to the historical data and the biological relevance is discussed and/or a confirmatory experiment is performed.

Results and discussion

Test results
Key result
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:
valid
Positive controls validity:
valid
Additional information on results:
- CYTOTOXICITY: in the pre-test the toxicity of the test item was examined using the determination of the cell number. Cell numbers of two cultures (10 coordinate defined fields per culture) were determined for each experimental group.- PRECIPITATION: In the pre-test on toxicity, precipitation of the test item after treatment was observed at 16 µg/ml and above in the absence of S9 mix and at 63 µg/ml and above in the presence of S9 mix. Since no clear toxicity was observed in the pre-test on toxicity, the test item was tested up to a concentration exhibiting clear test item precipitation as recommended in the OECD Guideline 473. Therefore, 50 µg/ml (without S9 mix) and 200 µg/ml (with S9 mix) were chosen as top treatment concentrations in the main experiment I.In conclusion, it can be stated that in the study described and under the experimental conditions reported, the test item did not induce structural Schromosome aberrations in V79 cells (Chinese hamster cell line).

Applicant's summary and conclusion