Benzene, C10-13-alkyl derivs.

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:

5 Jun 1989 to 8 Jun 1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Benzene, C10-13-alkyl derivs.

EC Number:

267-051-0

EC Name:

Benzene, C10-13-alkyl derivs.

Cas Number:

67774-74-7

Molecular formula:

C6 H5 Cn H2n+1; n= 10 to 13

IUPAC Name:

Benzene, C10-C13 Alkyl derivs.

Constituent 2

Reference substance name:

Undecylbenzene

EC Number:

229-806-2

EC Name:

Undecylbenzene

Cas Number:

6742-54-7

Molecular formula:

C17H28

IUPAC Name:

4-[undecan-(2 to 6)-yl] benzene

Test animals

Species:

mouse

Strain:

other: BRO:NMRI (SPF Han.)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: FA. Winkelmann
- Age at study initiation: young adult
- Weight at study initiation: about 26 g
- Fasting period before study: 18 hours
- Housing: 5 animals per cage in Makrolon Type III cages, identified by cage signs
- Diet: Ssniff R 10 - Alleindiat fur Ratten
- Water: Tap water, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1
- Humidity (%): 60 ± 10
- Photoperiod (hrs dark / hrs light): 12

Administration / exposure

Route of administration:

oral: gavage

Duration of treatment / exposure:

Single oral gavage exposure

Frequency of treatment:

Once

Post exposure period:

Animals were sacrificed at 24, 48, and 72 hours after exposure.

Doses / concentrations

Dose / conc.:

5 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

15 including negative controls and 5 in positive control group

Control animals:

yes

Positive control(s):

Positive control animals were given a single dose of 100 mg/kg cyclophosphamide. Negative control animals were given water instead of test substance.

Examinations

Tissues and cell types examined:

After sacrifice, the marrow from the thighs of each animal were removed and 2 mL fetal bovine serum was added. This suspension was centrifuged for 5 minutes. Marrow from each animals was divided into 3 slides, dried, and stained.

Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES:
Animals were given a single oral dose, and 5 animals of each sex per dose were sacrificed at 24, 48, and 72 hours after exposure.

DETAILS OF SLIDE PREPARATION:
Marrow from each animals was divided into 3 slides, dried, and stained.

METHOD OF ANALYSIS:
Cells were analysed by microscope ,1000 cells were analyzed per sample (3000/animal).

Evaluation criteria:

The nucleus of each cell was examined for size (micronucleus, which was considered 1/20th of the largest nucleus), and the number of polychromatid erythrocytes (PCE) to normochromatid erythrocytes (NCE).

Statistics:

F-test, t-test, and U-test were used to analyze the data.

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

diarrhea and diuresis was seen in test group animals

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Animals in the treatment group exhibited diarrhea and diuresis during the treatment period. There was a significant increase in the PCE/NCE ratio and PCE cells with micronucleus in the positive control group. There was no significant increase in either of these parameters in the treatment group.

Any other information on results incl. tables

Table 1: Results of Mouse Micronucleus Assay

	Dose (mg/kg)	Hours after application	% PCE with micronucleus	PCE/NCE
Positive control	100	24	3.34 ± 0.97	0.97 ± 0.07
Negative control	-	24	0.18 ± 0.06	1.15 ± 0.10
	-	48	0.25 ± 0.12	1.31 ± 0.09
	-	72	0.28 ± 0.10	1.20 ± 0.33
Treatment group	5000	24	0.20 ± 0.07	1.07 ± 0.10
	5000	48	0.18 ± 0.08	1.26 ± 0.16
	5000	72	0.18 ± 0.11	1.38 ± 0.20

Applicant's summary and conclusion

Conclusions:

Under the conditions described for this Mammalian Erythrocyte Micronucleus assay the tested substance did not reveal mutagenic properties.

Executive summary:

This study in accordance with OECD 474 and in compliance with GLP was performed to examine the mutagenic potential of the test substance in vivo. A groups of 15 female and 15 male mice were given a single dose of test substance to determine the effect on bone marrow. 5 animals of each sex were sacrificed at 24, 48, and 72 hours after exposure. Similar groups were exposed to cyclophosphamide (positive control), and water (negative control). All animals in the positive control group were sacrificed at 24 hours. Analysis of the bone marrow showed no significant increase in either micronucleus or polychromatid erythrocytes in the treatment group as compared to negative controls. The test substance is not mutagenic.