Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report Date:
1986

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
yes
Principles of method if other than guideline:
Mice or rats are recommended in the guideline. Chinese hamster were used in this study. Additionally, 1000 polychromatic erythrocytes/animal were scored for the incidence of micronuclei instead of 2000 claimed in the guideline.
GLP compliance:
no
Remarks:
not stated in the report
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: Commercial grade
- Lot/batch No.: Op. 11006
- Stability of test article: In the report it was stated that stability was guaranteed by the sponsor.



Test animals

Species:
hamster, Chinese
Strain:
other: random outbred
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Strain as stated in the report: Chinese hamster (Cricetulus griseus), random outbred strain
- Source: CIBA-GEIGY LTD. Tierfarm, Sisseln, Switzerland
- Age at study initiation: 6 - 10 weeks (males), 4 - 9 weeks (females)
- Weight at study initiation: 20 - 28 g (females), 23 - 33 g (males)
- Housing: individually
- Diet (ad libitum): standard diet, NAFAG No. 924
- Water (ad libitum): tap water

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 - 23
- Humidity (%): 48 - 51
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle: 0.5 % aqueous solution of sodium carboxymethylcellulose (CMC)
- Concentration of test material in vehicle: 5000 mg/kg bw in 20 ml/kg bw
Duration of treatment / exposure:
After single oral administration of 5000 mg/kg bw animals were observed for 16, 24 and 48 h.
Frequency of treatment:
Single oral administration.
Post exposure period:
16, 24 and 48 h.
Doses / concentrations
Remarks:
Doses / Concentrations:
5000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
16 animals (8 females, 8 males).
Control animals:
yes, concurrent no treatment
Positive control(s):
Animals treated with cyclophosphamide (64 mg/kg bw in 20 ml/kg bw 0.5 % CMC) served as positive control.

Examinations

Tissues and cell types examined:
Bone marrow was harvested from the shafts of both femurs. Normochromatic erythrocytes (NCE) as well as polychromatic erythrocytes (PCE) were counted for determination of the PCE/NCE-ratio. 1000 PCE per animal were used to determine the incidence of micronucleated PCE.
Details of tissue and slide preparation:
Bone marrow was harvested from the shafts of both femurs with a pipette and aspirated gently in 0.5 µl rat serum. Small drops of the mixture were transferred on a slide and spread out by pulling it behind a cover glass. The preparations were air-dried and stained in undiluted May-Grünwald solution (2 min) and subsequently in May-Grünwald solution/water 1/1 (2 min), followed by 20 minutes in 40 % Giemsa's. Following rinsing and washing with 55 % methanol and/or water, the slides were air-dried, cleared in Xylene and mounted in Eukitt.
Statistics:
The significance of difference was assessed by Chi square - test.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Remarks:
(Micronucleated PCE cells 0.18 % versus 0.13 % in negative control)
Toxicity:
no effects
Remarks:
(No significant difference in PCE/NCE-ratio between treated and negative control)
Vehicle controls validity:
valid
Negative controls validity:
other: see vehicle control
Positive controls validity:
valid

Any other information on results incl. tables

One female animal of the control group died during the experiment.

The percentage of micronucleated PCE was 0.13 % in the negative, 0.18 % in the treated group and 3.34 % in the positive control. As expected the positive control was statistically significantly different from negative control.

Applicant's summary and conclusion