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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: Comparable to guideline study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1996
Reference Type:
publication
Title:
Robust summary for 1,5,9-cyclododecatriene (revised).
Author:
DuPont Safety, Health & Environmental Excellence Center, Wilmington (Del., USA)
Year:
2003
Bibliographic source:
U.S. EPA, 46 pp
Reference Type:
publication
Title:
Support: Letter from DuPont Chem to USEPA re: Neurotoxicity inhalation toxicity study and a micronucleus inhalation study in rats with 1,5,9-cyclododecatriene,
Author:
DuPont Chem. (1996). Support: Letter from DuPont Chem to USEPA re:
Year:
1996
Bibliographic source:
NTIS/OTS Microfiche 0558489-1, Doc 89-960000191, dated 07/29/96.

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Male rats (mean pre-treatment weight for rats evaluated for micronuclei was 231.4 g; 51 days old when exposed) were exposed nose-only to the test substance or negative control, respectively, for 6 hours per day for 2 consecutive days.
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Constituent 1
Reference substance name:
1,5,9-cyclododecatriene
IUPAC Name:
1,5,9-cyclododecatriene
Details on test material:
TS: 1,5,9-cyclododecatriene, purity 100%

Test animals

Species:
rat
Strain:
other: Crl:CD (SD) BR
Sex:
male
Details on test animals or test system and environmental conditions:
- Age: 51 days
- Weight at study initiation: mean 231.4 g

Administration / exposure

Route of administration:
inhalation
Vehicle:
air
Details on exposure:
ADMINISTRATION: nose-only
- vapour atmosphere generated by metering the liquid test substance into a nebulizer
Sampling times and number of samples:   
- Test atmosphere: one sample during each exposure to determine  concentration and particle size distribution; result: 3200 +/- 280 mg/m3;  mass median aerodynamic diameter 3.6 µm   

Atmospheric concentration measured by gas chromatography and gravimetric analysis Aerosol/vapor atmospheres of 1,5,9-cyclododecatriene were generated by metering the liquid test substance into a nebulizer. Filtered, houseline air introduced into the nebulizer atomized the liquid test substance and carried the resulting aerosol/vapor mixture through a glass cyclone elutriator and into a glass transfer tube. Dilution air added to the transfer tube carried the aerosol/vapor/air mixture into the top of the exposure chamber. The concentration of 1,5,9-cyclododecatriene was controlled by varying the amount of test substance delivered into the nebulizer. Exposure chambers were constructed of stainless steel and glass with a nominal internal volume of approximately 150 L. The atmospheric concentration of 1,5,9-cyclododecatriene was determined at approximately 60-minute intervals during each exposure by gas chromatography and gravimetric analysis for the vapor and aerosol components, respectively. One sample to determine particle size distribution (mass median aerodynamic diameter) was taken from the 500 ppm chamber during the
study. Chamber airflow, temperature, relative humidity, and oxygen concentration were recorded.


Duration of treatment / exposure:
6 hours each on 2 consecutive days
Frequency of treatment:
once per day on 2 consecutive days
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
500 ppm = 3300 mg/m3 (aerosol/vapor)
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
3200 (+/- 280) mg/m3 (aerosol/vapour)
Basis:
analytical conc.
No. of animals per sex per dose:
No. of animals per dose: 10 exposed, 5 negative control
Control animals:
yes
Positive control(s):
40 mg cyclophosphamide/kg by oral intubation

Examinations

Tissues and cell types examined:
Bone marrow: At least 3 slides per rat (fixed, and stained with acridine orange), 2000 PCEs per rat scored for  micronuclei, 1000 erythrocytes scored for PCE/NCE ratio ; Representative slides from each rat were examined blindly.

further EXAMINATIONS: 
- Clinical observations: during exposure (including alerting stimulus)
- Organs examined at necropsy: marrow  from 1 femur
- Body weights: yes
Details of tissue and slide preparation:
Immediately after sacrifice, marrow from 1 femur of each rat was collected. At least 3 slides per rat were prepared, fixed, and stained with acridine orange.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
no mortalities
Additional information on results:
MORTALITY: no test substance-induced mortality

CLINICAL SIGNS:   
- During exposure: no clinical signs, response to alerting stimulus  diminished or absent   
- After exposure: lethargy and/or irregular respiration. 

BODY WEIGHT CHANGES: losses in treated and positive control rats

EFFECT ON MITOTIC INDEX OR PCE/NCE RATIO:    No statistically significant depressions in the proportion of PCEs  among 1000 erythrocytes were observed.

GENOTOXIC EFFECTS:    There were no statistically significant increases in the MNPCE  frequency in rats exposed to the test substance. A statistically  significant increase in the MNPCE frequency was found in the positive  control rats.

Any other information on results incl. tables

For each exposure, the mean aerosol concentration was added to the mean vapor concentration to calculate the total chamber atmospheric concentration of 1,5,9-cyclododecatriene. The analytically determined mean concentration in the exposure chamber targeted to 3300 mg/m3 (500 ppm) was 3200 ± 280 mg/m3 for the 2 exposures. The aerosol in the chamber was considered

respirable in rats with a mass median aerodynamic diameter of 3.6 μm; 23% of the particles were less than 3 μm and 99% of the particles were less than 10 μm. The chamber airflow, temperature, relative humidity, and oxygen concentration were 35 L/min, 23-25ºC, 15-22%, and 21%, respectively.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Under these experimental conditions, 1,5,9-cyclododecatreiene was considered as not genotoxic.
Executive summary:

Male rats were exposed nose-only to the test substance or negative control, respectively, for 6 hours per day for 2 consecutive days. Body weights and clinical signs were recorded. During exposure, all rats were observed for clinical signs of toxicity and for their reaction to an alerting stimulus. Immediately after sacrifice, marrow from 1 femur of each rat was collected. At least 3 slides per rat were prepared, fixed, and stained with acridine orange. Representative slides from each rat were examined blindly. Two thousand PCEs (polychromatic erythrocytes) per rat were evaluated for micronuclei. There was no test substance-induced mortality during the study. Statistically significant body weight losses were observed in the test substance-treated and the positive indicator rats. No clinical signs of toxicity were evident in rats during exposure. Rats in the treatment group did, however, display responses to an alerting stimulus ranging from diminished to none. Test substance-related clinical signs observed in the treatment group after exposure included lethargy and/or irregula r respiration, and likely represent manifestations of systemic toxicity.

There were no statistically significant increases in the MNPCE frequency in rats exposed to 1,5,9-cyclododecatriene. As expected, a statistically significant increase in MNPCE frequency was found in CP-treated rats. Additionally, no statistically significant depressions in the proportion of PCEs among 1000 erythrocytes were observed in rats exposed to the test substance.

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