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:
other information
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Purity: 98.6 %

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL Tierfarm Fuellinsdorf CH
- Age at study initiation: 10 weeks
- Weight at study initiation: 30g
- Assigned to test groups randomly: yes
- Fasting period before study: yes 18 hours
- Housing: singly in Makrolon type 1 with granulated softwood bedding
- Diet (e.g. ad libitum): Altromin standard diet, ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21+-3
- Humidity (%): 30-70%
- Air changes (per hr): not given
- Photoperiod (hrs dark / hrs light): 12 hours 6am-6pm

IN-LIFE DATES: From: 17-09-1990 To: 05-11-1990

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Polyethylene glycol 400
Details on exposure:
10 mL/kg bw
Duration of treatment / exposure:
single dose administered on day 1
Frequency of treatment:
single dose
Post exposure period:
24, 48 and 72 hours
Doses / concentrationsopen allclose all
Dose / conc.:
100 mg/kg bw (total dose)
Dose / conc.:
333 mg/kg bw (total dose)
Dose / conc.:
1 000 mg/kg bw (total dose)
No. of animals per sex per dose:
5 (five)
Control animals:
yes, concurrent vehicle
Positive control(s):
40 mg/kg bw cyclophosphamid

Examinations

Tissues and cell types examined:
bone marrow smears; 1000 polychromatic erythrocytes
Details of tissue and slide preparation:
bone marrow extracted with fetal calf serum; centrifuged and the pellet resuspended. small drop of resuspended cell pellet spread on slide and air dried. Stained with May-Grunwald/Giesma.
Evaluation criteria:
A test article is classified as mutagenic if it induces either a statistically significant dose related increase in the number of micronucleated polychromatic erythrocytes or a reproducible statistically significant positive response for at least one of the test points.
A test article producing neither a statistically significant dose-related increase in the number of micronucleated polychromatic erythrocytes nor a reproducible statistically significant positive response at anyone of the test points is considered non-mutagenic in this system.
Statistics:
non-parametric Mann-Whitney test

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
positive
Toxicity:
yes
Vehicle controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

 test group  dose mg/kg bw

 sampling time (h)

 PCE with MNE

 range

 PCE/NCE

 vehicle

 0

 24

 0.06%

 0 -2

 1000/845

test substance 

 100

 24

 0.09%

 0 -4

 1000/904

 test substance

 333

 24

 0.16%

 0 -6

 1000/898

 test substance

 1000

 24

 0.21% *

 0 -4

 1000/936

 positive control  40  24  1.08% *  7 -20  1000/972
 vehicle  0  48  0.06%  0 -2  1000/898
 test substance  1000  48  0.39% *  0 -9  1000/1016
 vehicle  0  72  0.1%  0 -3  1000/682
 test substance  1000  72  0.475%  1 -8  1000/1261

* = P<0.05% by the Mann Whitney non parametric test

Applicant's summary and conclusion

Conclusions:
Based upon the findungs of this study o-chlorobenzotrichloride is considered to be mutagenic in the micronucleus assay.
Executive summary:

In comparison to the negative control a dose dependent increase in the frequenccy of micronuclei 24 hours after the application of the test item was observed. A statistically significant increase in the micronucleated polychromatic erythrocyte frequencies was observed for the highest dose group.