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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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-guideline study

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1995
Reference Type:
secondary source
Title:
Methanesulfinic acid, Aminoimino, CAS No: 1758-73-2
Author:
OECD SIDS
Year:
2002
Bibliographic source:
OECD SIDS; UNEP Publications

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
adapted in 1983
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
adopted un 1992
Deviations:
no
GLP compliance:
yes
Remarks:
Hessisches Ministerium für Umwelt, Energie und Bundesangelegenheiten
Type of assay:
micronucleus assay

Test material

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

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL, Füllinsdorf, Germany
- Age at study initiation: approx. 8 – 12 weeks
- Weight at study initiation: 30.4 ± 15.5 g (males); 25.6 ± 1.2 (females)
- Fasting period before study: approx. 18 h
- Housing: individual in Macrolon cages Type I, with wire mesh top, and granulated soft wood bedding
- Diet: pelleted standard diet (Altromin 1324), ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3
- Humidity (%): 30 – 70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used:distilled water
Duration of treatment / exposure:
not applicable
Frequency of treatment:
single treatment
Post exposure period:
24, 48, and 72 h after treatment
Doses / concentrations
Remarks:
Doses / Concentrations:
600 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
6
Control animals:
yes, concurrent vehicle
Positive control(s):
30 mg cyclophosphamide/kg bw
cyclophosphamide
- Route of administration: oral
- Doses / concentrations: 30 mg/kg bw

Examinations

Tissues and cell types examined:
Tissue: bone marrow
Cell type: bone marrow cells
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Range finding study to find the maximum tolerated dose level
TREATMENT AND SAMPLING TIMES: the animals were sacrificed by cervical dislocation. The femora were removed, the epiphyses were cut off and the marrow was flushed out with fetal calf serum, using a syringe. The cell suspension was centrifuged for 10 min and the supernatant was discarded. A small drop of the suspended pellet was spread on a slide.
DETAILS OF SLIDE PREPARATION: slides were stained with May-Grünwald/Giemsa-solution
METHOD OF ANALYSIS: evaluation of the slides was performed using NIKON microscopes with 100 x immersion oil objectives. 1000 polychromatic erythrocytes (PCE) were analysed per animal for micronuclei. To describe a cytotoxic effect the ratio between polychromatic and normochromatic erythrocytes was determined in the same sample and expressed in normochromatic erythrocytes per 1000 PCEs. The analysis was performed with coded slides.
Evaluation criteria:
The test item is classified as mutagenic if it induces a statistically significant increase in the number of micronucleated polychromatic erythrocytes for at least one of the test points.
A test item producing no statistically significant increase in the number of micronucleated polychromatic erythrocytes at any of the test points is considered non-mutagenic under the test conditions.
However, both biological and statistical significance should be considered together.

Statistics:
Non-parametric Mann-Whitney test.

Results and discussion

Test results
Sex:
not specified
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
RESULTS OF RANGE-FINDING STUDY
- Dose range: 600 – 1200 mg/kg bw
- Clinical signs of toxicity in test animals: 1200 mg/kg bw: reduction of spontaneous activity, was observed in 2/2 males and 2/2 females at 1, 6, 24, and 48 h after exposure and in 1/2 males and 1/2 females at 72 after exposure. Eyelid closure: was observed in 2/2 males and 1/2 females, at 1, 6, and 24 h and in 1/2 males and female at 48 h post-exposure. Apathy was observed in 2/2 males and 1/2 males at 1 and 24 h after exposure, in 2/2 males and females 6 h after exposure and in 1/2 male and females at 48 h after exposure.

RESULTS OF DEFINITIVE STUDY
The mean number of normochromatic erythrocytes was not increased after treatment with formamidine sulfinic acid as compared to the mean values of NCEs of the negative control, indicating that formamidine sulfinic acid had no cytotoxic properties in the bone marrow. There was no enhancement in the frequency of the detected micronuclei in comparison to the negative control at any preparation interval after administration of formamidine sulfinic acid. 30 mg/kg bw cyclophosphamide administered per os was used as positive control which showed a statistically significant increase of induced micronucleus frequency.

Any other information on results incl. tables

Table 1. Micronuclei in polychormatic erytrhrocytes (PCE) and relationship PCE/NCE (NCE= normochromatic erythrocytes)

Dosemg/kg bw

Sampling time

PCEs withMicronulei

Range

PCE/NCE

0

24 h

0.14 %

0 - 4

1000/880

600

24 h

0.12 %

0 - 3

1000/881

600

48 h

0.11 %

0 - 3

1000/889

600

72 h

0.11 %

0 – 3

1000/839

Cyclophohamide, 30

72 h

0.11%

0 - 3

1000/941

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
During the study described and under the experimental conditions reported, formamidine sulfinic acid did not induce micronuclei as determined by the micronucleus test with bone marrow cells of the mouse. Therefore, formamidine sulfinic acid is considered to be non-mutagenic in this micronucleus assay.