5H-1,2-oxathiole 2,2-dioxide

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Similar to OECD 474; read-across data

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

not specified

Type of assay:

mammalian erythrocyte micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

1,3-propanesultone

EC Number:

214-317-9

EC Name:

1,3-propanesultone

Cas Number:

1120-71-4

Molecular formula:

C3H6O3S

IUPAC Name:

1,2-oxathiolane 2,2-dioxide

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Wako Pure Chemical Industries, Ltd., Osaka, Japan; WDM4950
- Purity: >97%

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male

Details on test animals or test system and environmental conditions:

Mice were given commercial pellets and water ad libitum throughout the acclimatization and experimental periods.

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: Saline

Duration of treatment / exposure:

2 IP injections, 24 hrs apart

Frequency of treatment:

Twice (24 hrs apart)

Post exposure period:

24, 48, 72 hrs

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

9 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

18 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

36 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

72 mg/kg bw/day (nominal)

No. of animals per sex per dose:

6 males

Control animals:

yes, concurrent no treatment

Positive control(s):

- Mitomycin C
- Justification for choice of positive control(s):
- Route of administration: single IP injection; sampled at 48 hrs
- Doses / concentrations: 0.5 mg/kg

Examinations

Tissues and cell types examined:

Peripheral blood reticulocytes

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The highest dose was fixed by the preliminary dose-finding test, and the micronucleus assay was performed at three levels – the highest dose and 1/2 and 1/ 4 of the highest dose. The highest dose was based on mortality.

METHOD OF ANALYSIS: Micronucleated polychromatic erythrocyte and micronucleated reticulocyte frequencies were based on the observation of at least 1000 polychromatic erythrocytes or reticulocytes per animal.

Evaluation criteria:

An expert committee evaluated each chemical considering the judgement by the investigators who performed the experiment, p-values, reproducibility, magnitude of response and biological significance. Although biological significance is difficult to judge, we took into account dose-response relationships, the kinetics of micronucleus appearance, the historical control levels when available, and the absolute magnitude of the response.

Statistics:

Pair-wise comparisons were made between the 0 hr sampling data and later sampling data. When the control data were acceptable, the increase in micronucleus frequency against the concurrent negative control data was evaluated using a conditional binomial test and the dose-response relationship was evaluated using the Cochran-Armitage trend test. When these were both significant, the data was declared positive. If neither step showed significance, the data was judged negative. All other cases were called inconclusive.

Results and discussion

Test results

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Remarks:

LD50 (MTD) = 290 mg/kg bw

Vehicle controls validity:

not specified

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): There was a statistically significant increase (p<0.05) in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs (Table 1)
- Statistical evaluation: The results of the Cochran-Armitage trend tests were all 0.000.

Any other information on results incl. tables

Table 1: Micronucleus assay results

% of MNPCE or MNRET (after the final treatment)
Dose	0 h	24 h		48 h		72 h
mg/kg bw	mean±SD	mean±SD	p	mean±SD	p	mean±SD	p
9	0.08± 0.04	0.17± 0.10	0.151	0.10± 0.13	0.500	0.08± 0.10	0.623
18	0.10± 0.11	0.23± 0.10	0.058	0.10± 0.11	0.613	0.07± 0.05	0.828
36	0.12± 0.08	0.87± 0.53	0.000	0.63± 0.16	0.000	0.28± 0.16	0.032
72	0.10± 0.09	1.92± 0.99	0.000	1.68± 0.50	0.000	0.27± 0.14	0.026

p = value of pairwise comparisons. The results of the Cochran-Armitage trend tests were all 0.000.

Applicant's summary and conclusion

Conclusions:

In an in vivo micronucleus assay in male CD-1 mice, there was a statistically significant increase in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs.

Executive summary:

In a CD-1 mouse peripheral blood micronucleus assay (Morita et al., 1997), groups of 6 male mice were treated by IP injection with 1,3-Propanesultone (>97%) in saline at doses of 9, 18, 36 and 72 mg/kg bw/day. A peripheral blood sample was taken from each animal immediately before treatment (0 hrs; control) and then the animals were dosed twice (0, 24 hrs) and peripheral blood was sampled at 24, 48 and 72 hrs. The positive control was Mitomycin C (0.50 mg/kg bw). Micronucleated polychromatic erythrocyte and micronucleated reticulocyte frequencies were based on the observation of at least 1000 polychromatic erythrocytes or reticulocytes per animal.

There was a statistically significant increase (p<0.05) in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs. The results of the Cochran-Armitage trend tests were all 0.000. Therefore, 1,3-Propanesultone induced micronucleated reticulocytes in male CD-1 mice by double intraperitoneal treatments starting at relatively low doses.