Registration Dossier

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as ‘reliable without restriction’ because it followed relevant acceptable guidelines (OECD, U.S. EPA TSCA and FIFRA, and EC Method B12) and was GLP compliant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): C20-C24 alkenes, branched and linear
- Substance type: Alkenes, C20-24
- Physical state: Liquid
- Analytical purity: 100%
- Lot/batch No.: C1829-50A
- Storage condition of test material: Room temperature

Test animals

Species:
mouse
Strain:
other: Crl:CD-1TM (1CR)BR
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Limited, Margate, Kent, England
- Age at study initiation: 5 to 8 weeks old
- Weight at study initiation: 23 to 30 grams
- Assigned to test groups randomly: Yes, following an unspecified method
- Housing: Groups of up to seven in suspended cages
- Diet (e.g. ad libitum): Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 22°C
- Humidity (%): 59 to 75%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours light

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used: Arachis oil
- Justification for choice of solvent/vehicle: Not reported
- Concentration of test material in vehicle: 50, 100, or 200 mg/mL
- Lot/batch no. (if required): T24
Details on exposure:
Crl:CD-1TM(1CR)BR mice were dosed intraperitoneally at 500, 1000, or 2000 mg/kg body weight.
Duration of treatment / exposure:
Single exposure
Frequency of treatment:
Single exposure
Post exposure period:
48 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
500, 1000, or 2000 mg/kg
Basis:
nominal conc.
No. of animals per sex per dose:
Seven males per group
Control animals:
yes, concurrent vehicle
Positive control(s):
Cyclophosphamide
- Justification for choice of positive control(s): Not reported
- Route of administration: Oral
- Doses / concentrations: 50 mg/kg

Examinations

Tissues and cell types examined:
Bone marrow, erythrocytes (polychromatic and normochromatic)
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Doses were selected based on a preliminary study.


TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Animals from all groups were sacrificed at 24 hours. A second group of vehicle and 2000 mg/kg animals were sacrificed at 48 hours.


DETAILS OF SLIDE PREPARATION: Femurs were dissected and aspired with foetal calf serum. Bone marrow smears were prepared following centrifugation for 30 seconds at approximately 6000 rpm and re-suspension. The smears were air-dried, fixed in absolute methanol and stained in May-Grunwald/Giemsa, allowed to air-dry and coverslipped using mounting medium.


METHOD OF ANALYSIS: The incidence of micronucleated cells per 2000 polychromatic erythrocytes per animal was scored. In addition, the number of normochromatic erythrocytes associated with 1000 erythrocytes were counted and scored for the incidence of micronuclei. The ratio of polychromatic to normochromatic erythrocytes was also calculated.


Evaluation criteria:
A statistically significant and dose responsive increase in the number of micronucleated polychromatic erythrocytes was considered a positive response. A significantly lower polychromatic/normochromatic ratio was considered indicative of bone marrow toxicity.

Statistics:
A two-tailed Student's t-test was performed on log transformed data. Results were confirmed using a one-way analysis of variance.

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:
RESULTS OF RANGE-FINDING STUDY
- Dose range: 1000 to 2000 mg/kg
- Solubility: Not reported
- Clinical signs of toxicity in test animals: None
- Evidence of cytotoxicity in tissue analyzed: Tissues were not analyzed
- Rationale for exposure: To find the maximum tolerated dose up to the limit dose of 2000 mg/kg

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): None
- Ratio of PCE/NCE (for Micronucleus assay): No effect
- Appropriateness of dose levels and route: Considered appropriate
- Statistical evaluation: Appropriate statistical methods were used.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Intraperitoneal administration of C20-C24 alkenes, branched and linear, did not result in an increase in the frequency of polychromatic erythrocytes. The test material was reported to be non-genotoxic under the conditions of the test.
Executive summary:

In a preliminary range finding study, 2 male and 2 female Crl:CD-1TM(1CR)BR mice were dosed intraperitoneally at 1000 or 2000 mg/kg body weight and observed for 3 days for clinical signs of toxicity and mortality. There were no signs of clinical toxicity or mortality observed in either male or female mice in the range-finding study. Based on a lack of significant difference in the toxic response to C20-24 alkenes between the sexes, only male mice were used in the main study.

 

In the main study, C20-24 alkenes was administered to seven male Crl:CD-1TM(1CR)BR mice intraperitoneally at 500, 1000, or 2000 mg/kg bodyweight. A vehicle control group (arachis oil, seven male mice) and a positive control group (cyclophosphamide, five male mice) were also utilized in the study. Mice were sacrificed at 24 hours. Seven males per group were exposed to vehicle or 2000 mg/kg and sacrificed at 48 hours. All animals were observed for signs of toxicity and mortality. Following sacrifice bone marrow was extracted from the femur; smears were prepared and subsequently evaluated for an increase in the frequency of polychromatic erythrocytes (PCEs).

 

There were no signs of clinical toxicity or mortality in male mice dosed with 500, 1000, or 2000 mg/kg in the micronucleus assay. No statistically significant increases in the number of PCEs or decreases in the PCE/NCE (normochromatic erythrocytes) ratio were observed in male mice at any treatment level.

 

Intraperitoneal administration of C20-C24 alkenes, branched and linear, did not result in an increase in the frequency of PCEs. The test material was reported to be non-genotoxic under the conditions of the test.