Registration Dossier

Administrative data

Endpoint:
in vivo mammalian cell study: DNA damage and/or repair
Remarks:
Type of genotoxicity: DNA damage and/or repair
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1999
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No guideline study, well documented

Data source

Reference
Reference Type:
publication
Title:
Induction of unscheduled DNA synthesis in hairless mouse epidermis by skin carcinogens
Author:
Mori et al
Year:
1999
Bibliographic source:
J Tox Sci; Vol 24, 3, p.217-226

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Skin epidermis instead of liver cells were investigated for unscheduled DNA synthesis after topical application of the test item to mouse skin.
GLP compliance:
no
Type of assay:
unscheduled DNA synthesis

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
other: HOS-HR1
Sex:
female
Details on test animals and environmental conditions:
Food and water ad libitum. 12 h dark/light cycle.

Administration / exposure

Route of administration:
dermal
Vehicle:
acteone
Details on exposure:
before applying the test substance, the skin was stripped with a cellulose tape.
Duration of treatment / exposure:
2 h
Frequency of treatment:
once
Post exposure period:
none
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
topical application
Basis:
nominal conc.
0.5%
Remarks:
Doses / Concentrations:
topical application
Basis:
nominal conc.
1%
Remarks:
Doses / Concentrations:
topical application
Basis:
nominal conc.
2%
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
yes

Examinations

Tissues and cell types examined:
skin epidermis
Evaluation criteria:
Ratio between DNS synthesis in presence and absence of hydroxy urea.

Results and discussion

Test results
Sex:
female
Genotoxicity:
negative
Toxicity:
not examined
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
In this test system no unscheduled DNA synthesis was induced with the test item.
Executive summary:

In an adopted UDS assay, five mice received a single topical dose (0, 0.5, 1, 2%) of the test item. The skin epidermis was extracted and the unscheduled DNA synthesis was assessed using (3H)dTHd as marker. and a liquid scintillation counter as detector. No DNA synthesis was induced by the test item. The positive controls (DMBA, MNNG, BaP) were valid..