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
Study period:
1996
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions: (1) Both sexes were not evaluated and (2) bone marrow smears were not prepared at more than 1 time point after the multiple exposure regimen.

Data source

Reference
Reference Type:
publication
Title:
Robust summary and test plan for 1,5-cyclooctadiene with cover letter dated 11 Dec 2002
Author:
DuPont Safety, Health & Environmental Excellence Center, Wilmington (Del., USA)
Year:
2002
Bibliographic source:
Quelle U.S. EPA 37 pp

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Principles of method if other than guideline:
Method: Based on OECD Guideline 474 (1983), EPA Guideline 40 CFR 798.5935, and others
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
1,5-cyclooctadiene, purity >99%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male
Details on test animals and environmental conditions:
TEST ORGANISMS: 
- rats Crl:CD(R)(SD)BR 
- Age: 52-53 days
- Weight at study initiation: 229.2-246.8 g
- No. of animals per dose: 10 exposed, 5 per control group

Administration / exposure

Route of administration:
inhalation
Vehicle:
air
Details on exposure:
TYPE OF INHALATION EXPOSURE: - whole body exposure
GENERATION OF TEST ATMOSPHERE
- Vapor atmospheres were generated by metering the liquid test substance into a heated flask with a syringe infusion pump
- atmospheric concentration was determined by gas chromatography
EXAMINATIONS: 
- Clinical observations: yes
Duration of treatment / exposure:
6 hours/day for 2 consecutive days
Frequency of treatment:
2 consecutive days
Post exposure period:
24 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
0 or 1500 ppm (6750 mg/m3)
Basis:

No. of animals per sex per dose:
10 exposed, 5 per control group
Control animals:
yes, concurrent vehicle
Positive control(s):
positive control cyclophosphamide, exposure only on day 2

Examinations

Tissues and cell types examined:
polychromatic erythrocytes of the bone marrow from femur
Details of tissue and slide preparation:
ADMINISTRATION: 
- Duration of test: Sacrifice on day 3, approximately 24 hours after the  end of the second exposure
- Sampling times and number of samples: Immediately after sacrifice,  marrow from 1 femur of each rat was aspirated, prepared, and at least 2 
 slides per animal were prepared, fixed, and stained in acridine orange.  Prior to scoring, a coverslip was floated on each slide. 
- Control groups and treatment:   
negative control air,   
positive control cyclophosphamide, exposure only on day 2
Evaluation criteria:
Criteria for evaluating results: statistically significant and  biologically relevant increase in frequency of micronucleated  polychromatic 
erythrocytes of the test group as compared to the  negative control group
Statistics:
Data for the proportion of MNPCEs among 2000 PCEs and the proportion of PCEs among 1000 erythrocytes were transformed prior to analysis using
the arcsine square root funktion. Transformed data were analyzed separatelyfor normality of distribution and equal variance using the Shapiro-Wilk and Bartlett's tests.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls valid:
yes
Negative controls valid:
not applicable
Positive controls valid:
yes
Additional information on results:
MORTALITY: 
No test substance-induced mortality was observed.
CLINICAL SIGNS: 
Depression or absence of an alerting response mainly  during the latter half of the exposures; incoordination was evident in  
3/10 rats during the first exposure and in all treated rats after this  first exposure. 2/10 rats exhibited abnormal gait after the second  exposure. 
Irregular respiration was observed in 6/10 rats after the first  exposure and in 3/10 rats after the second exposure.
BODY WEIGHT CHANGES: 
Losses in 9/10 rats after the first exposure and in  all rats after the second exposure.
EFFECT ON MITOTIC INDEX OR PCE/NCE RATIO: 
No statistically significant  increase in the frequency of micronucleated PCEs was observed in treated  rats. A statistically significant depression in the proportion of PCEs  among 1000 erythrocytes was observed in the treatment group, indicative  of testsubstance-induced bone marrow toxicity. A 
statistically  significant increase in MNPCE frequency was found in the positive control  rats.

Any other information on results incl. tables

no further remarks

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Under the conditions of this in vivo study 1,5-cyclooctadiene did not induce micronucleated polychromatic erythrocytes in male rats.
Executive summary:

In this in vivo rat micronucleus test 10 male rats were exposed for 6 hours/day for 2 consecutive days to 1500 ppm 1,5-cyclooctadiene.

5 male rats were exposed to the negative control (air). Bone marrow polychromatic erythrocytes, collected 24 hours after the last

exposure, were examined microscopically for micronucleated polychromatic erythrocytes (PCE).

No statistically significant increase in the frequency of  micronucleated PCE's was observed in treated rats. A statistically significant depression in the proportion of PCEs among 1000 erythrocytes was observed in the treatment group, indicative

of testsubstance-induced bone marrow toxicity. A statistically significant increase in MNPCE frequency was found in the positive 

control  rats.

Under the conditions of this in vivo study 1,5-cyclooctadiene did not induce micronucleated polychromatic erythrocytes in male rats.