Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

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

Study period:

July 16, 1984 - November 15, 1984

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:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

21. July 1997

Deviations:

yes

Remarks:

only one time point observed

Principles of method if other than guideline:

The test was conducted according to the procedures of Boller et al. (1970, Humangenetik 11, 35-54), Matter et al. (1970, Mutation Res. 12, 417-425) and Müller et al. (1972, Verh. Dtsch. Ges. Path. 56, 381-384).

GLP compliance:

no

Remarks:

but QAU statement included

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

EC Number:

255-392-8

EC Name:

Thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]

Cas Number:

41484-35-9

Molecular formula:

C38H58O6S

IUPAC Name:

2-[(2-{[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl]oxy}ethyl)sulfanyl]ethyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate

Details on test material:

- Physical state: solid
- Analytical purity: > 99.5% (CIBA-GEIGY Ltd, Analyse Number: 5659, 25.10.1984)

Test animals

Species:

hamster, Chinese

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: CIBA-GEIGY Tierfarm, Sisseln
- Age at study initiation: females: 6-10 weeks, males 4-9 weeks
- Weight at study initiation: females: females: 22-30 g, males: 22-33 g
- Fasting period before study: no data
- Housing: single
- Diet: NAFAG No.924
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 - 24
- Humidity (%): 59 - 68
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: 0.5% aqueous solution of CMC (carboxymethyl cellulose)

Duration of treatment / exposure:

two days

Frequency of treatment:

daily one application on 2 consecutive days

Post exposure period:

24 hours

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

875 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

1 750 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

3 500 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

6

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide
- Doses / concentrations: 128 mg/kg

Examinations

Tissues and cell types examined:

Tissue: bone marrow
Cell type: bone marrow cells

Details of tissue and slide preparation:

DETAILS OF SLIDE PREPARATION:
Bone marrow cells were transferred on the end of a slide, spread out by pulling it behind a polished cover glass and the preparations were air-dried. Three hours later, the slides were stained in undiluted May-Gruenwald solution for 2 min then in May-Gruenwald solution/water 1/1 for 2 min and then in Giemsa's, 40% for 20 min. After being rinsed in methanol 55% for 5-8 sec and washed off twice in water, they were left immersed in water for approx. 2 min. After rinsing with distilled water and air-drying, the slides were cleared in Xylene and mounted in Eukitt.

METHOD OF ANALYSIS:
The slides of three female and three male animals each of the negative control group, the positive control group and of the groups treated with various doses of test substance were examined. 1000 bone marrow cells each were scored per animal and the following anomalies were registered:
a) Single Jolly bodies, b) fragments of nuclei in erythrocytes, c) micronuclei in erythroblasts, d) micronuclei in leucopoietic cells, e) polyploid cells.

Statistics:

The significance of difference was assessed by X² -test.

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

Any other information on results incl. tables

Table 1: Effects of the test substance and cyclophosphamide on bone marrow cells of chinese hamser

			Percent of cells with anomalies of nuclei
	# of animals	sex	single jolly bodies	Fragment of nuclei in erythrocytes	Micronuclei in erythrocyblasts	Micronuclei in leucopoietic cells	Polyploid cells	Total
Control	1	female	0.2					0.2
	2	female						0
	3	female						0
	4	male						0
	5	male	0.1					0.1
	6	male						0
Cyclophosphamide (128 mg/kg bw)	1	female	10.4	2.8	2			15.2
	2	female	9.8	3	1.7	0.2		14.7
	3	female	9.8	1.7	1.7	0.2		13.4
	4	male	7.8	1.3	1.1	0.1		10.3
	5	male	6.1	1.2	2.6	0.1		10
	6	male	8.5	1.6	1.3	0.1		11.5
Test substance (875 mg/kg bw)	1	female						0
	2	female						0
	3	female	0.2					0.2
	4	male						0
	5	male						0
	6	male						0
Test substance (1750 mg/kg bw)	1	female	0.1					0.1
	2	female	0.1					0.1
	3	female	0.2					0.2
	4	male	0.1					0.1
	5	male	0.1					0.1
	6	male	0.1					0.1
Test substance (3500 mg/kg bw)	1	female						0
	2	female						0
	3	female						0
	4	male						0
	5	male						0
	6	male						0

The bone marrow smears from animals treated with various doses of the test substance showed no significant difference from the control. The incidence of bone marrow cells with anomalies of nuclei corresponds to the frequency observed in the control group. By contrast, a "positive control" experiment with cyclophosphamide (128 mg/kg) yielded 12.5% cells with anomalies of nuclei. This is significantly different from the controls (0.05%) treated with the vehicle (0.5% CMC) alone.

Applicant's summary and conclusion

Conclusions:

It is concluded that under the conditions of this experiment, no evidence of mutagenic effects was obtained in Chinese hamsters treated with the test article.

Executive summary:

The in vivo genotoxic potential of the test substance was evaluated in a micronucleus test in bone marrow erythrocytes of young, male and female chinese hamsters similar in designs to OECD guideline 474. Treatment consisted of one daily dose of 875, 1750 or 3500 mg/kg on each of two consecutive days. The animals were sacrificed 24 h after the second application and bone marrow smears were prepared. The incidence of bone marrow cells with anomalies of nuclei corresponds to the frequency observed in the control group. By contrast, a positive control experiment with cyclophosphamide (128 mg/kg) yielded 12.5% cells with anomalies of nuclei. This is significantly different from the controls (0.05%) treated with the vehicle (0.5% CMC) alone. It is concluded that under the conditions of this experiment, no evidence of mutagenic effects was obtained in Chinese hamsters treated with the test substance.