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Toxicological information

Genetic toxicity: in vivo

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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline 474 study conducted under GLP. The study was selected as a key study because the information provided for the hazard is sufficient to evaluate the need for classification and labelling and/or risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutshcland
- Assigned to test groups randomly: yes
- Diet : ad libitum
- Water :ad libitum
- Acclimation period:5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70%
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12 hours

Administration / exposure

Route of administration:
inhalation: gas
Vehicle:
- Vehicle(s)/solvent(s) used: none - test material is a gas and exposure was by inhalation
Details on exposure:
TYPE OF INHALATION EXPOSURE: nose only


GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:nose-only inhalation chamber - cylindrical column, surrounded by a transparent hood. Test atmosphere from the bottom and the exhaust at the top. The column volume was ~ 70 liters.
- Method of holding animals in test chamber: plastic animal holders
- Source and rate of air:
- Temperature, humidity, pressure in air chamber: 20-24C, 30-70% humidity,
- Air flow rate: 10.7 - 20.0 l/min (20 l/min group had 10 animals)
- Air change rate:
- Treatment of exhaust air:


TEST ATMOSPHERE
- Brief description of analytical method used: total carbon analyzer
- Samples taken from breathing zone: yes
Duration of treatment / exposure:
4 hour
Frequency of treatment:
once
Post exposure period:
24 - 48 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 12500, 50000, and 200000 ppm
Basis:
analytical conc.
No. of animals per sex per dose:
5 (10 at 200000 ppm)
Control animals:
yes, sham-exposed
Positive control(s):
mitomycin C
- Justification for choice of positive control(s): known to cause micronuclei
- Route of administration: intraperitoneal
- Doses / concentrations: 0.75 mg/kg

Examinations

Tissues and cell types examined:
bone marrow cells
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: 200000 ppm is 20% of the atmosphere which can reduce the amount of oxygen in the air

DETAILS OF SLIDE PREPARATION: method according to Schmidd (1976). Two smears per animals, air dired and fixed with methanol, stained with May-Grunwald Geimsa solution.


METHOD OF ANALYSIS: microscopic evaluation
Evaluation criteria:
A test substance is considered to cause chromosomal damage and/or damage to the mitotic apparatus. if the mean number of MPF2000 PE is statistically significantly higher, when compared to the mean number of the vehicle controls.
A test substance is considered to be negative in the micronucleus test if it produces no positive response at the used dose level.
Both statistical significance and biological relevance are considered together in the evaluation.
Statistics:
ANOVA - MPE and PE. If significant, followed by pooled error variance t-test (pooled or separate depending if the variances were homogenous or not)

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The test substance did not cause cytotoxicity to the bone marrow cells.

Any other information on results incl. tables

In the positive control group, the mean number of the micronucleated polychromatic erythrocytes (MPE) per 2000 polychromatic erythrocytes (PE) was statistically significantly higher from the negative control group A (***p <0.001). This demonstrates the validity of the test system.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
These data support the conclusion that under the conditions used in this study, the test substance was not cytotoxic to the bone marrow and did not produce micronuclei in polychromatic erythrocytes in male mice following 4 hour inhalation exposure to 200000 ppm (932000 mg/m3) test substance.

From the results obtained it is concluded that this micronucleus test did not show any indication of chromosomal damage and/or damage to the mitotic apparatus of the bone marrow target cells in male mice following acute Inhalation exposure to the test substance.