Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro DNA damage and/or repair study
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July 15, 1985 - August 13, 1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 482 (Genetic Toxicology: DNA Damage and Repair, Unscheduled DNA Synthesis in Mammalian Cells In Vitro)
GLP compliance:
yes (incl. certificate)
Type of assay:
DNA damage and repair assay, unscheduled DNA synthesis in mammalian cells in vitro

Test material

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

Method

Species / strain
Species / strain / cell type:
hepatocytes: Adult male F344 rats
Details on mammalian cell type (if applicable):
- Type and identity of media: WME
Metabolic activation:
without
Test concentrations with justification for top dose:
40, 133, 400, 1333, 4000 ug/well
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
Controls
Untreated negative controls:
yes
Remarks:
untreated WME only
Negative solvent / vehicle controls:
yes
Remarks:
water
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-acetylaminofluorene
Remarks:
final concentration of 1 x 10 E-5 M
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: Cells were exposed to test substance in 10 uCi/ml 3[H] thymidine-WME for 18 to 20 hours.
- Fixation time (start of exposure up to fixation or harvest of cells): Cells were fixed 18 to 20 hours after inititation of exposure to test substance.


NUMBER OF REPLICATIONS: 3


NUMBER OF CELLS EVALUATED: a total of 60 cells per dose point were counted

DETERMINATION OF CYTOTOXICITY
- Method: unscheduled DNA repair synthesis is evidenced by a net increase in black silver grains over the nucleus. This is quantified by determining nuclear and cytoplasmic grain counts (Artek 880 automated colony counter with microscopic / video camera attachment)


Evaluation criteria:
The test substance is reported positive when the minimum net grain count of 5 per nucleus was consistently observed in triplicate wells. Where possible, a dose response profile should be observed.

Results and discussion

Test results
Species / strain:
hepatocytes: Adult male F344 rats
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
following doses were tested: 0.13, 0.4, 1.3, 4.0, 13, 40, 133, 400, 1333 and 4000 ug/well.
The test article was nontoxic.

COMPARISON WITH HISTORICAL CONTROL DATA:
The negative and positive control values were within the acceptable range of mean historical data

ADDITIONAL INFORMATION ON CYTOTOXICITY:
no cytotoxicity observed.
Remarks on result:
other: all strains/cell types tested

Any other information on results incl. tables

None of the treated cultures produced net nuclear grain counts that were substantially greater than the solvent control (water).

Applicant's summary and conclusion

Conclusions:
Result of the test: negative without metabolic activation
Under the conditions of this study, the test substance was not genotoxic in the hepatocyte primary culture/DNA repair test. This conclusion is based upon the finding of the inability of the test substance to produce a mean nuclear grain count of 5 or greater than the vehicle control mean net nuclear grain count at any level of concentration.