Aminoiminomethanesulphinic acid

Genetic toxicity: in vivo

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

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1995

Reference 2

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

adapted in 1983

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

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

Test material information

Constituent 1

Reference substance name:

Aminoiminomethanesulphinic acid

EC Number:

217-157-8

EC Name:

Aminoiminomethanesulphinic acid

Cas Number:

1758-73-2

Molecular formula:

CH4N2O2S

IUPAC Name:

aminoiminomethanesulphinic acid

Test material form:

solid

Test animals

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system 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.