Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented report of a guideline study conducted according to GLP.

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 475 (Mammalian Bone Marrow Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
chromosome aberration assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): OS 61349J (CASRN = 15214-89-8)
- Substance type: organic
- Physical state: solid
- Analytical purity: not specified
- Impurities (identity and concentrations): not specified
- Composition of test material, percentage of components: 100%
- Purity test date: not specified
- Lot/batch No.: not specified
- Expiration date of the lot/batch: not specified
- Stability under test conditions: stable
- Storage condition of test material: room temerature, protected from light

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 8-9 weeks old
- Fasting period before study: no



Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle used: water
Frequency of treatment:
single dose
Post exposure period:
6, 18 and 24 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
150; 500 and 1500 mg/kg
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide
- Route of administration: gavage
- Doses / concentrations: 30 mg/kg

Examinations

Tissues and cell types examined:
Bone marrow cells
Details of tissue and slide preparation:
Bone marrow cells were centrifuged and resuspended in fresh hypotonic solution and incubated for 20 minutes at 37°C in a water bath. Following hypotonic treatment, cells were centrifuged and resuspended in fixative solution of 3 parts methanol and 1 part acetic acid. Cells were treated with fresh fixative solution 4 times by centrifugation and resuspension. Drops of the concentrated cell suspension were placed on clean moist glass slides. Slides were dried at least 24 hours and stained with 5% Gurr R66 Giesma for approximately 5-6 minutes at room temperature. The cell harvest, slide preparation and staing techniques followed standard cytogenic procedures.
Statistics:
The percentage of cells with chromosomal aberration were analyzed by the statistical methods described by Margolin et al., Environmental Mutagenesis, Volume 8, 1986.

Results and discussion

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

Any other information on results incl. tables

Clinical signs observed in the animals dosed at 1500 mg/kg included increased respiratory rate (50%), watery feces (28%), soft feces (17%), and wheezing (1%). Mean body weights of the dose groups were not significantly different from the vehicle control group at any time point. As is illustrated in Table 1 below, the test article did not produce statistically significant increases (p<0.05) in the percentage of cells with aberrations at any dose, time period or for either sex, compared to control values. Positive control animals treated with cyclophosphamide (30 mg/kg) demonstrated an increase in the frequency of damaged cells which was statistically significant at the study threshold of p<0.05. Thus, the positive and negative controls demonstrated the reliability of the assay to detect chromosomal aberrations.

Table 1:

 Male                    Female

 Time

(hours)

 Treatment

 Dose

(mg/kg)

% cells with

aberrations  

 Time

(houirs)

 Treatment

 Dose

(mg/kg)

  % cells with

aberrations

 6  Vehicle    3.2  6  Vehicle    2.0
    OS61349J  150  0.8     OS61349J  150  2.0
     500  1.6      500  0.8
     1500  1.2      1500  1.2
 18  Vehicle    0.4  18    Vehicle  0.4
    OS61349J  150  0.4     OS61349J   150  1.2
     500  0.4      500  0.8
     1500  0.8      1500  1.2
 24  Cyclophosphamide  30  18.8  24   Cyclophosphamide  30  19.2
    Vehicle    0.8    Vehicle    1.6
    OS61349J  150  0.0     OS61349J  150  1.2
     500  0.8      500  2.4
     1500  0.8      1500 0.8

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
The test material was non-clastogenic in rat bone marrow cells under the conditions of the assay.