Icos-1-ene

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

1982-10-11 to 1982-12-03

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because although it contained a GLP statement, all relevant study data was not included with the study report

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Hex-1-ene

EC Number:

209-753-1

EC Name:

Hex-1-ene

Cas Number:

592-41-6

IUPAC Name:

hex-1-ene

Details on test material:

- Name of test material (as cited in study report): Gulftene 6
- Substance type: C6 alpha olefin
- Physical state: Liquid
- Storage condition of test material: 2-10° C under an inert atmosphere
-Other: Colourless, extremely volatile liquid

Test animals

Species:

mouse

Strain:

Swiss

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Kingston, New York
- Age at study initiation: 12 weeks
- Weight at study initiation: 35 to 43 grams (Males); 26 to 33 grams (Females)
- Assigned to test groups randomly: No, animals assigned serially to dose groups
- Housing: Individually prior to testing and 2/cage during exposure
- Diet (e.g. ad libitum): ad libitum except during exposure
- Water (e.g. ad libitum): ad libitum except during exposure
- Acclimation period: 19 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 0.0°C
- Humidity (%): 52 ± 2.8%
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light

IN-LIFE DATES: From: 1982-10-11 To: 1982-12-03

Administration / exposure

Route of administration:

inhalation: vapour

Vehicle:

- Vehicle(s)/solvent(s) used: air
- Concentration of test material in vehicle: 1000; 10,000; and 25,000 parts per million

Details on exposure:

TYPE OF INHALATION EXPOSURE: Whole body

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 2 mice per cage inserted into a 0.26 cubic meter stainless steel and glass dynamic chamber held at negative pressure.
- Method of conditioning air: Filtration
- System of generating particulates/aerosols: Ball-jet nebuliser (Ohio Medical Products)
- Temperature, humidity, pressure in air chamber: 24.6°C; 41.38%; Pressure not reported
- Method of particle size determination: Mass median aerodynamic deviation (MMAD) determination using an aerodynamic particle sizer (TSI, Inc. Model APS 33)

TEST ATMOSPHERE
- Brief description of analytical method used: 100 micro-litre sample withdrawn from the gas chamber using a gas-tight syringe followed by analytical concentration determination by gas chromatography.
- Samples taken from breathing zone: Yes

Duration of treatment / exposure:

2 hours/exposure

Frequency of treatment:

2 days

Post exposure period:

1 day post cessation of treatment

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1000
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
10,000 ppm
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
25,000 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

5 sex/dose

Control animals:

yes

Positive control(s):

- Positive control: Cyclophosphamide
- Justification for choice of positive control(s): Cyclophosphamide is a standard approved positive control material for this test
- Route of administration: Intraperitoneal injection
- Doses / concentrations: 75 mg/kg

Examinations

Tissues and cell types examined:

Bone marrow smears were stained with May-Grunwald and Giemsa stains and evaluated microscopically for micronucleated polychromatic erythrocytes (PCEMs).

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: No data reported.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Test and control materials were administered on days 1 and 2. Samples for analytical determination were collected prior to and during exposure.

DETAILS OF SLIDE PREPARATION: Test and negative control animals were sacrificed on days 3 and 4 of the study period. Positive control animals were sacrificed on day 3 of the study period. Bone marrow smears were prepared on the day of sacrifice by staining with May-Grunwald and Giemsa stains followed by microscopic evaluation at 400-1000x magnification.

METHOD OF ANALYSIS: Polychromatic erythrocytes (PCE's), PCE's with micronuclei (PCEM's), normochromatic erythrocytes (NORM's) and NORM's with micronuclei were identified by analyzing 1000 PCE's and mature erythrocytes in the scan path. Group means and standard deviations for PCE's with micronuclei and group mean ratio of PCE's to NORM's were calculated for each dose group. Subsequently test group mean values were compared vehicle controls and historical data using the student's t-test.

Evaluation criteria:

The test is considered positive if a significant (P<0.05) increase in micronucleated PCE's is observed at any dose level and if a dose-related response is evident. The test is considered negative if neither criterion applied and equivocal if only one is satisfied.

Statistics:

Body weight, Total PCE's, NORM's, PCE's with micronuclei, NORM's with micronuclei: Means and standard deviation calculated for each dose group and student's t-test used to evaluate differences between treatment and control groups.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): Percent micronuclei induced by the administration of Gulftene 6 was observed to be normal in the treatment groups when compared with the negative control (air only) and historical data. Cyclophosphamide (positive control) treated animals showed statistically significant (P<0.05) elevations in the number of micronuclei induced.
- Ratio of PCE/NORM (for Micronucleus assay): Statistically significant elevations in the PCE/NORM ratio was observed in five female mice sacrificed on day 3 and treated at 1000; 10,000; and 25,000 ppm Gulftene 6. However, similar statistically significant differences were not observed in the other five females sacrificed on day 4. Male and female mice treated with cyclophosphamide showed statistically significant (P<0.05) differences when compared to data from negative controls.

Any other information on results incl. tables

Male mice transferred from individual to collective cages for exposure displayed aggressive behaviour that resulted in the death of one animal on day 3. Lethargy and rapid respiration were observed in mice exposed to Gulftene 6 at dose levels of 10,000 and 25,000 parts per million. However, recovery was evident post-exposure when these animals were returned to an air only atmosphere. Although mean group body weights of female mice treated at 25,000 ppm were statistically lower than corresponding controls on days 1 and 3, the same was not observed on day 4 of the study period. No other treatment-related changes in mean group body weights were noted in either male or female.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Whole body inhalation exposure to Gulftene 6 upto dose levels of 25,000 parts per million does not result in an increase in the formation of micronucleated polychromatic erythrocytes (PCEMs). Thus, Gulftene 6 is negative in this in vivo micronucleus test in the mouse bone marrow.

Executive summary:

In a (Crl:CDR-1 (ICR) BR Swiss) mouse bone marrow micronucleus assay, 5 mice/sex/dose were treated (whole body inhalation exposure) with Gulftene 6 at doses of 0; 1000; 10,000; or 25,000 parts per million for a period of 2 hours on two consecutive days. Bone marrow cells were harvested post sacrifice on either day 3 or 4 of the study period. Animals in the negative control group were exposed to clean, filtered air alone while animals in the positive control group were treated via intraperitoneal injection to 75 mg/kg cyclophosphamide.

Lethargy and rapid respiration were observed in animals treated at 10,000 and 25,000 parts per million but these clinical effects were reversible post-exposure. 50 percent of the female mice exhibited statistically lower mean body weights on days 1 and 3. However, mean body weights of the remaining female mice were observed to be normal when compared to corresponding control animals. No significant increase in the frequency of micronucleated polychromatic erythrocytes in the bone marrow was noted after treatment at any dose level. Male and female animals induced with cyclophosphamide exhibited a statistically higher frequency of micronucleated polychromatic erythrocytes in the bone marrow when compared with negative controls.

This study received a Klimisch score of 2 and is classified as reliable with restriction because all relevant study data was not included in the study report.