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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 gudieline study conducted under GLP
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EPA OPPTS 870.5395 (In Vivo Mammalian Cytogenetics Tests: Erythrocyte Micronucleus Assay)
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Remarks:
US laboratory, no certificate available
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Kingston NY
- Assigned to test groups randomly: yes
- Diet : ad libitum
- Water :ad libitum
- Acclimation period: 2 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.0 to 22. 1°C
- Humidity (%): 20.0 to 22. 1°C
- 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, 100,000 ppm
Basis:
analytical conc.
No. of animals per sex per dose:
10
Control animals:
yes, sham-exposed
Positive control(s):
Cyclophosphamide
- Justification for choice of positive control(s): known to cause micronuclei
- Route of administration: intraperitoneal
- Doses / concentrations: 40 mg/kg

Examinations

Tissues and cell types examined:
bone marrow cells
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: 100,000 ppm is 10% of the atmosphere which can reduce the amount of oxygen in the air


TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):


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


OTHER:
Evaluation criteria:
A positive response is normally indicated by a statistically significant increase in the incidence of
micronucleated polychromatic erythrocytes for the treatment group compared with the concurrent
negative control group (P<0.01); individual and/or group mean values should exceed the laboratory
historical negative control range (Morrison and Ashby 1995). A negative result is indicated where
individual and group mean incidences of micronucleated polychromatic erythrocytes for the group treated
with the test substance are not significantly greater than incidences for the concurrent negative control
group (P>0.01) and where these values fall within the historical negative control range. An equivocal
response is obtained when the results do not meet the criteria specified for a positive or negative
response.
Statistics:
The results for each treatment group were compared with the results for the concurrent negative control group using non-parametric statistics.As there was considered to be no difference between the sexes, the induced micronuclei frequency for both sexes were combined to facilitate interpretation and maximise the power of statistical analysis.
For incidences of micronucleated polychromatic erythrocytes, exact one-sided P-values are calculated by permutation (StatXact, CYTEL Software Corporation, Cambridge, Massachussetts). For assessment of effects on the proportion of polychromatic erythrocytes, equivalent permutation tests based on rank scores are used, ie exact versions of Wilcoxon's sum of ranks test.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls valid:
not applicable
Negative controls valid:
yes
Positive controls valid:
yes
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
HFO-1234ze did not show any evidence of causing an increase in micronuclei or bone marrow cell toxicity when administered to CD-1 mice for a single 4-hour nose-only inhalation exposure in this in vivo test procedure.