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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:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1995

Materials and methods

Principles of method if other than guideline:
The assay was performed as described by Jaylet et al. (1986) and according to the recommendations of the French standard AFNOR T-90-325 (AFNOR, 1987) revised in 1992 (AFNOR, 1992).
Briefly, larvae at stage 53 of the developmental table established by Gallien and Durocher (1957) were used for the experiment, since at this stage the mitotic index is at a maximum (Deparis, 1973). The highest concentration to be used in the 12-day micronucleus assay is defined as half the minimum concentration that led to detectable physiological disturbances (weight loss, swelling, reduction in food intake, swimming in circles, etc.) in a 6-day preliminary toxicity test. In every glass container, the water (containing the dissolved chemical at the required concentration) was renewed daily. After 12 days of treatment, blood samples were taken from every animal (15-20 larvae per concentration) by cardiac puncture into an heparinized micropipette. The slides (one for each animal) were stained with Masson acid Hemalun and the number of micronucleated erythocytes was counted in a sample of 1000 erythrocytes.
GLP compliance:
not specified
Type of assay:
other: Newt micronucleus test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
other: Pleurodeles waltl larvae
Sex:
not specified
Details on test animals and environmental conditions:
Test organisms were provided by the Centre de Biologie du Développement, University P. Sabatier (Toulouse, France) and acclimatized for one week before the experiment.

Administration / exposure

Route of administration:
other: test organisms in water containing the test substance
Vehicle:
water (containing the dissolved chemical at the required concentration)
Duration of treatment / exposure:
12 days
Doses / concentrationsopen allclose all
Dose / conc.:
1.25 other: µg/ml
Dose / conc.:
2.5 other: µg/ml
Dose / conc.:
5 other: µg/ml
No. of animals per sex per dose:
15-20 larvae per concentration

Examinations

Tissues and cell types examined:
Blood, erythrocytes
Details of tissue and slide preparation:
Blood samples were taken from every animal by cardiac puncture into an heparinized micropipette. The slides were stained with Masson acid Hemalun and the number of micronucleated erythocytes was counted in a sample of 1000 erythrocytes.
Evaluation criteria:
A compound is considered as genotoxic if:
(1) it induces a statistically significant increase in the number of micronucleated erythrocytes compared to the control (p < 0.05) and
(2) the median for the treated group is at least twice as high as the control median.
In case the second condition is not fulfilled, the chemical is considered as weakly genotoxic.
Statistics:
As there is not a normal distribution of micronucleus frequencies, median values and quartiles were calculated instead of mean values. The statistical method of Mac Gill et al. (1978), a quick and reliable test adapted to small sample sizes and values that do not have normal distribution, was used to analyse the results.

Results and discussion

Test results
Sex:
not specified
Genotoxicity:
positive
Remarks:
1.25-2.5 (clastogenic effects)
Toxicity:
yes
Remarks:
10 µg/ml

Applicant's summary and conclusion