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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1989-02-28 to 1989-03-03
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified ‘reliable without restriction’ because the study is scientifically acceptable, well conducted and documented, and adheres to the OECD guideline 474 recommendations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

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): Oronite XS 101
- Substance type: 1-Dodecene dimer with 1-decene, hydrogenated
- Physical state: Liquid
- Analytical purity: 100% as manufactured
- Impurities (identity and concentrations): None reported
- Composition of test material, percentage of components: Not reported
- Lot/batch No.: KWA 88-01217
- Stability under test conditions: Considered stable
- Storage condition of test material: Ambient temperature protected from light

Test animals

Species:
mouse
Strain:
Swiss
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratory, Portage, Michigan
- Age at study initiation: 49 days old
- Weight at study initiation: Males: 25.8 to 35.0 grams; Females: 19.5 to 30.1 grams
- Assigned to test groups randomly: Yes, under following basis: by weight
- Housing: Groups of 5 per sex in polycarbonate cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 14 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): approximately 21°C
- Humidity (%): 35 to 53%
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light


IN-LIFE DATES: From: 1989-02-28 To: 1989-03-03

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used: Peanut oil
- Justification for choice of solvent/vehicle: Not reported
- Concentration of test material in vehicle: 0.470, 0.332, or 0.210 g/mL
- Lot/batch no. (if required): 807493A
- Purity: Not reported
Details on exposure:
Animals were administered 1.56 to 6.25 mL/kg body weight by intraperitoneal injection. All treated animals received 4.0 g/kg (4.40 mL/kg) peanut oil in addition to the test material.
Duration of treatment / exposure:
One injection
Frequency of treatment:
Once
Post exposure period:
72 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 1250, 2500, 5000 mg/kg body weight
Basis:
no data
No. of animals per sex per dose:
18 mice per sex per dose except high-dose which used 21 mice per sex
Control animals:
yes, concurrent vehicle
Positive control(s):
triethylenemelamine
- Justification for choice of positive control(s): This compound is known to produce micronuclei.
- Route of administration: Interperitoneal injection
- Doses / concentrations: 0.25 mg/kg in isotonic saline

Examinations

Tissues and cell types examined:
Bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Not reported


TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): Samples were taken at 24, 48, and 72 hours; positive controls were obtained at 24 hours


DETAILS OF SLIDE PREPARATION: Mice were sacrificed by cervical dislocation. The marrow from the femur was aspirated from the bone and placed into a 0.5-millilitre conical bottom beaker containing approximately 0.4 millilitres foetal bovine serum and centrifuged (2000 rpm, 5 minutes, at room temperature). The supernatant was decanted and the pellet was resuspended in the residual serum. Two bone marrow smears were made from each animal according to the method of Schmid. The slides were fixed in methanol and stained with 4% Giemsa for approximately 20 minutes.

METHOD OF ANALYSIS: The polychromatic erythrocytes were recognized as bluish-gray, non-nucleated cells of the same approximate size as the mature orange-pink normochromatic erythrocytes. Micronuclei were recognized as round, darkly stained, blue-purple, sharply contoured particles which were 1/20 - 1/5 the size of the cell, and which were in the same focal plane as the cell. The selected slides were coded and analyzed using a Zeiss Photoscope III with 63x Planapo oil immersion lens without knowledge of treatment. The ratio of normochromatic erythrocytes to polychromatic erythrocytes and the %polychromatic erythrocytes (of total erythrocytes) was calculated by counting a total of 1000 erythrocytes. On each slide, 1000 polychromatic erythrocytes were evaluated for the presence of micronuclei. The number of micronuclei in normochromatic erythrocytes was also tallied. After the slides were scored, they were decoded.


OTHER: One slide per animal was scored and the second was maintained as a backup.
Evaluation criteria:
If no statistically significant difference was detected, the results were negative. If a difference was detected, the dose response was analyzed. If this test detected a trend at the 5% level, the results were considered to be positive. If a trend was not detected, the Study Director evaluated the variability observed in the vehicle control and the nature of the statistically significant responses. The results were declared negative, inconclusive, or positive after consideration of all contributing factors. A test material was judged negative if the highest dose given was the maximum tolerated dose, and all dose-time points fell in the negative classification described above.

Statistics:
A one-tailed Fisher exact test and a binomial approximation test were used to examine differences between control and treatment groups. Since multiple comparisons were made, Bonferroni corrections were made to adjust the probability value required for significance. If a difference was detected, the dose response was analyzed using the one-tailed Cochran-Armitage test for trend in binomial proportions.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): No increase in micronuclei was observed.
- Ratio of PCE/NCE (for Micronucleus assay): No increase in PCE/NCE was observed.
- Appropriateness of dose levels and route: The highest dose was the maximum practical dose to administer.
- Statistical evaluation: There were no statistical changes observed with between the test compound results and the vehicle control results. Positive controls demonstrated a significant increase in micronuclei compared to the control.

Any other information on results incl. tables

Cytotoxicity was observed in positive control males and in male mice treated at 1250 mg/kg at 24 hours. Cytotoxicity was also seen at 48 hours in female mice treated with Oronite XS 101 at 2500 mg/kg and 5000 mg/kg.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Oronite XS 101 is negative in the micronucleus assay in the mouse bone marrow erythrocytes.
Executive summary:

In a Swiss albino Crl:CDR-1 (ICR)BR mouse bone marrow micronucleus assay, 18/sex/dose were treated with a single intraperitoneal injection of Oronite XS 101 at doses of 0, 1250, 2500, or 5000 mg/kg bw. Bone marrow cells were harvested at 24, 48, and 72 hours post-treatment from 5 mice/sex/group/time point. The vehicle was peanut oil. Positive controls received 0.25 mg/kg triethylenemeamine in isotonic saline via intraperitoneal injection.

 

There were no signs of toxicity during the study. Cytotoxicity was observed in positive control males and in male mice treated at 1250 mg/kg at 24 hours. Cytotoxicity was also seen at 48 hours in female mice treated with Oronite XS 101 at 2500 mg/kg and 5000 mg/kg. Oronite XS 101 was tested at an adequate dose because the highest dose tested was the maximum practical dose that could be administered. The positive control induced the appropriate response. There was not a significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow after any treatment time.

 

This study received a Klimisch score of 1 and is classified as reliable without restrictions because the study is scientifically acceptable, well conducted and documented, and adheres to the OECD guideline 474 recommendations.

This study will influence the DNEL.