Reaction mass of m-cresol and 2-chloro-m-cresol and 6-chloro-m-cresol

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:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP compliant study similar to OECD guideline 474 with some deviations: Only one dose level tested, vehicle produced signs of toxicity, only 1000 erythrocytes/animal scored for micronuclei.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

yes

Remarks:

Only one dose level tested, vehicle produced signs of toxicity, only 1000 erythrocytes/animal scored for micronuclei.

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

Chlorocresol

EC Number:

200-431-6

EC Name:

Chlorocresol

Cas Number:

59-50-7

Molecular formula:

C7H7ClO

IUPAC Name:

4-chloro-3-methylphenol

Details on test material:

- Name of test material (as cited in study report): Preventol CMK
- Physical state: White to colourless crystalline powder
- Analytical purity: 99.96%
- Lot/batch No.: 280
- Storage condition of test material: Approved for use during the study period.

Test animals

Species:

mouse

Strain:

other: Bor:NMRI (SPF Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: F. Winkelmann, Borchen, Germany
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 29-44 g bw

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle used: Polyethyleneglycol 400 (PEG 400)
- Concentration of test material in vehicle: Test substance: 25 mg/mL , Pos. control: 2 mg/mL (in deionised water)

Details on exposure:

The test substance was dissolved in PEG 400 and applied intraperitoneal (i.p.) via injection. The total volume applied was 5 mL/kg bw for the control and treated groups and 10 mL/kg bw for the positive control. Animals were sacrificed depending on their allocation to the different grups 24, 48 and 72 hours after application. The control groups were sacrificed 24 hours after application of PEG 400.

Duration of treatment / exposure:

not applicable

Frequency of treatment:

Not applicable as only one single application was performed.

Post exposure period:

treatment group: 24, 48 and 72 hours
control group: 24 hours
positive control: 24 hours

Doses / concentrations

Remarks:

Doses / Concentrations:
125 mg/kg bw
Basis:
other: actual applied intraperitoneal (i.p.)

No. of animals per sex per dose:

5 per sex per dose

Control animals:

yes, concurrent no treatment

Positive control(s):

cyclophosphamide (20 mg/kg bw),

Examinations

Tissues and cell types examined:

Femoral bone marrow smears were prepared 24, 48 and 72 h after i.p. administration of the test substance according to Schmid´s method (Schmid, W. Mut. Res. 31, 9-15, 1975 and DFG, Kommission für Mutagenitätsfragen, Mitteilungen III, 53-61, 1975). The ratio of polychromatic to normochromatic erythrocytes was determined. In addition all animals were examined for clinical signs of toxicity after administration of the test substance.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

Animals of the control and treatment group showed clinical signs of toxicity. Four mice died during the study period.

Vehicle controls validity:

other: Animals of the negative control group showed apathy and spasm, lasting for up to 24 hours. Thereafter, their external appearance and physical activity remained unaffected.

Negative controls validity:

not applicable

Positive controls validity:

valid

Any other information on results incl. tables

Clinical signs of toxicity:

Animals treated with 125 mg/kg bw test substance showed symptoms of toxicity which comprised apathy, roughened fur, staggering gait, prone position, spasm, twitching and diarrhoea. The symptoms lasted until sacrifice.
Animals of the negative control group showed apathy and spasm, lasting for up to 24 hours. Thereafter, their external appearance and physical activity remained unaffected. Their feeding behavior was normal.

In the positive control group no symptoms of toxicity were noted.

 

Mortality:

4 of 40 treated animals died during the test period. The time points of death are listed in the following:

24 hours group: 1 male found dead after 24 hours

48 hours group: 1 female found dead after 48 hours

72 hours group: 1 male found dead after 48 hours

Replacement group: 1 male found dead after 72 hours

 

Details on Genotoxicity:

The ratio of polychromatic to normochromatic erythrocytes was not altered in the groups which received the test substance (see Table 1). No indications of clastogenic effects of the test substance were found after treatment.

The positive control cyclophosphamide caused a clear clastogenic effect which is shown by the significant increase of polychromatic erythrocytes with micronuclei. The ratio of polychromatic to normochromatic erythrocytes was not altered (see Table 1).

Table 1: Results of the Micronucleus test in mice

Experimental group	Time of sacrifice [hours after treatment]	Number of evaluated polychromatic erythrocytes per animal	No. of normo­chromatic erythro­cytes per 1000 poly­chromatic erythro­cytes [mean ± SD]	Micronucleated cells per 1000
				normochromatic erythrocytes [mean ± SD]	polychromatic erythrocytes [mean ± SD]
Negative control^a	24	1000	1179 ± 495	1.3 ± 1.1	1.2 ± 0.9
Test substance^b	24	1000	1319 ± 439	0.7 ± 0.9	1.3 ± 1.4
Test substance^b	48	1000	1595 ± 633	1.2 ± 0.9	0.7 ± 0.8
Test substance^b	72	1000	1524 ± 1185	0.7 ± 0.7	1.1 ± 0.7
Positive control^c	24	1000	881 ± 160	1.3 ± 1.2	16.1* ± 6.4
^aPolyethyleneglycol 400 (as intraperitoneal injection) ^b125 mg/kg bw (as intraperitoneal injection) ^c20 mg/kg bw cyclophosphamide (as intraperitoneal injection) * p < 0.01 in non-parametric Wilcoxon ranking test

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative