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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
Type of information:
experimental study
Adequacy of study:
key study
Study period:
September 1983
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1983

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
no
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Test animals

Species:
mouse
Strain:
Swiss
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: approximately six weeks old
- Fasting period before study: overnight before first dose administration
- Acclimation period: five days

ENVIRONMENTAL CONDITIONS
- Temperature: 22-24 °C
- Air changes: 16 per hour
- Photoperiod: 12 hours light/12 hours dark

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: 1 % tragacanth suspension
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Dosages were given as two equal administrations separated by a 24 hour interval in a volume of 0.1 mL/10 g body weight prepared in 1 % tragacanth suspension
Duration of treatment / exposure:
Two doses were administered over a 24 hour period
Frequency of treatment:
Two single doses were administered separated by a 24 hour period
Post exposure period:
Six hours after the second dose, the animals were sacrificed.
Doses / concentrationsopen allclose all
Dose / conc.:
300 mg/kg bw (total dose)
Dose / conc.:
600 mg/kg bw (total dose)
Dose / conc.:
1 200 mg/kg bw (total dose)
No. of animals per sex per dose:
Five per sex per dose
Control animals:
yes, concurrent vehicle
Positive control(s):
- mitomycin C
- Doses / concentrations: 0.4 mg/mL in sterile buffered saline

Examinations

Tissues and cell types examined:
Femur bone marrow
Details of tissue and slide preparation:
Bone marrow was removed by injection of New Born calf serum into the femur. The serum and bone marrow suspension was centrifuged for 5 minutes at 800 rpm. The supernatant was removed and a bone marrow smear made from the pellet.

After air-drying overnight, the smears were fixed in methanol for 5 minutes and then successively placed in 1.25 % May-Grünwald for 15 minutes and in 3 % Giesma for 20 minutes. After rinsing in buffered distilled water, the slides were air-dried and mounted in Depex.
Evaluation criteria:
Smears were examined to determine the incidence of micronucleated cells per 1000 polychromatic erythrocytes per animal and the ratio of normochromatic to polychromatic erythrocytes.

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Remarks:
All micronucleated cell counts for the test material were within the concurrent control range. The mean normochromatic/polychromatic ratio was 0.85
Toxicity:
no effects
Remarks:
No mortalities were noted in any of the doses administered
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
No mortalities were observed.

At all dose levels, the mean micronucleated cell counts were in the same range as the counts obtained for the negative control group.

The mean ratios of normochromatic to polychromatic erythrocytes obtained for all dose levels were in the same range as those of the vehicle control group.

Any other information on results incl. tables

Table 1: Group mean results

    Number of micronucleated cells per 1000 erythrocytes Ratio of normochromatic to polychromatic erythrocytes
 Material Total dose (mg/kg) Mean Range Mean Range
 1% tragacanth  -  0.2  0 - 1  0.85  0.56 - 1.51
 Test material  1200  0.2  0 - 1  0.92  0.58 - 1.61
   600  0.8  0 - 3  0.77  0.58 - 1.02
   300  0.5  0 - 1  0.74  0.56 - 1.09
 Mitomycin C  *  32.8  12 - 54  1.91  0.90 - 2.90

* 0.16 mg/animal  

Applicant's summary and conclusion

Conclusions:
Under the conditions of the test, the test material did not show any evidence of mutagenic potential for polychromatic erythrocytes of mice.
Executive summary:

In a non-GLP compliant micronucleus test considered to be equivalent or similar to EU Method B.12, the genetic toxicity of the test material was determined.

No mortalities were observed. At all dose levels, the mean micronucleated cell counts were in the same range as the counts obtained for the negative control group. The mean ratios of normochromatic to polychromatic erythrocytes obtained for all dose levels were in the same range as those of the vehicle control group.

Under the conditions of this test, the test material showed no evidence of mutagenic potential for polychromatic erythrocytes of mice.