C.I. Acid Yellow 246

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

ion

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 September 1984

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

GLP compliance:

no

Type of assay:

micronucleus assay

Test material

Test material information

Test material form:

solid: particulate/powder

Test animals

Species:

mouse

Strain:

other: OF-1 albino mice

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: IFFA-CREDO, L'Arbresle, France
- Weight at study initiation: 25 g
- Assigned to test groups randomly: yes
- Housing: Animals were housed 5 of the same sex per cage in Makrolon type III cages
- Diet: Aliment Rats-Souris Charles River, produced by U.A.R., Villemoisson/Orge, France ad libitum
- Water: ad libitum
- Acclimation period: 1 week

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

distilled water

Details on exposure:

A preliminary range finding test by treating three groups of three male mice at concentrations of 3000, 2000 and 1000 mg/kg were conducted. For the micronucleus test, each treatment group was comprised of five male and five female mice receiving one intragastric intubation (2500 mg/kg) using 0.5 ml of a solution at 125 mg/ml per 25 g body weight.

Duration of treatment / exposure:

20, 44 and 68 h

Frequency of treatment:

single application

Post exposure period:

20, 44 and 68 h for main test

Doses / concentrations

Remarks:

Doses / Concentrations:
2500 mg/kg
Basis:
nominal conc.

No. of animals per sex per dose:

5

Control animals:

yes

Positive control(s):

Thio-TEPA

Examinations

Tissues and cell types examined:

Two types of erythrocytes were observed in the bone marrow smears: normochromatic (mature red blood cells about to pass into the blood stream) and polychromatic (immature red blood cells) . The latter are stained blue by Giemsa for around 24 h after the expulsion of the erythroblast nucleus: the colouration is probably due to traces of RNA remaining in these cells.

Details of tissue and slide preparation:

After sacrifice of the animals the femurs were taken and broken open at one end. Bone marrow cells were suspended in foetal calf serum using a small syringe, and the cells were centrifuged at 120 x g for 5 minutes. The supernatant was removed with a Pasteur pipette, cells were spread on a microscope slide and the smears allowed to dry in air. The following day smears were stained with Giemsa (1:6 in water) and mounted after drying with a coverslip.

Statistics:

A complete statistical analysis, using BMPD computer programme 7D is performed.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

At low magnification of the microscope no noticeable differences in bone marrow nucleated cells were observed between animals treated with FAT 20'306/B and negative controls.
In the positive control group (Thio-TEPA) decreased numbers of bone marrow nucleated cells were noted.

Any other information on results incl. tables

There was no statistically significant increase in the number of micronucleated polychromatic erythrocytes in animals exposed to 2500 mg/kg of FAT 20306/B compared to negative control animals. In animals treated with Thio-TEPA there was a statistically significant increased number of micronucleated cells. The ratio of polychromatic to normochromatic erythrocytes was markedly decreased in mice treated with Thio-TEPA. There was no difference between animals treated with FAT 20306/B and the negative control for this ratio.

Applicant's summary and conclusion

Conclusions:

FAT 20306/B did not present a mutagenic effect in the micronucleus test using mice treated by oral administration at 2500 mg/kg.

Executive summary:

The micronucleus test was performed to assess mutagenicity toxicity of the test article based on OECD 474. The test article was administered orally to mice at concentration of 2500 mg/kg body weight. There was no statistically significant increase in the number of micronucleated polychromatic erythrocytes in animals exposed to 2500 mg/kg of FAT 20306/B compared to negative control animals. In animals treated with Thio-TEPA there was a statistically significant increased number of micronucleated cells (pronounced evidence of mutagenicity 44 h after administration). The ratio of polychromatic to normochromatic erythrocytes was markedly decreased in mice treated with Thio-TEPA. There was no difference between animals treated with FAT 20306/B and the negative control for this ratio. Thus, we can conclude the test article dose not present a mutagenic effect to mice.