2-naphthol

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: A well documented study according to OECD and GLP guidelines. In the OECD SIDS on 2-Naphthol (2002) a similar reliability was assigned.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

2-naphthol

EC Number:

205-182-7

EC Name:

2-naphthol

Cas Number:

135-19-3

Molecular formula:

C10H8O

IUPAC Name:

2-naphthol

Details on test material:

Purity:99.5%

Test animals

Species:

mouse

Strain:

other: BDF1 (C57BL/6 x DBA/2)

Sex:

male

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

2-naphthol was given suspended in 0.5% methylcellulose solution.
Dosage volume was 0.1 mL/kg bw in the dose-finding and the main tests.

Duration of treatment / exposure:

Exposure period: 2days

Frequency of treatment:

Once daily for consecutive two days with 24-hour intervals.

Post exposure period:

Mice were observed for the mortality for 24 hrs after the second administration.

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (control), 62.5, 125 or 250 mg/kg bw
Basis:
other: The doses in the main test were determined based on the results of the dose-finding test where the following doses were tested 62.5, 125, 250, 500 or 1000 mg/kg bw.

No. of animals per sex per dose:

Dose finding test: male and female mice (three/sex/group) were given 2-naphthol suspended in 0.5% methylcellulose solution at 62.5, 125, 250, 500 or 1000 mg/kg bw
Main test: Six male mice at 0 (control), 62.5 and 125 mg/kg bw, and eight male mice at 250 mg/kg bw.
Five specimens per group were examined.

Control animals:

yes, concurrent vehicle

Positive control(s):

Control animals were given 0.5% methylcellulose solution only by gavage.
Dosage volume was 0.1 mL/kg bw in the dose-finding and the main tests.
Positive control animals were once injected intraperitoneally with mitomycin C at 0.5 mg/kg bw.

Examinations

Tissues and cell types examined:

The animals were killed 24 hours after the second administration, and slides were prepared for bone marrow cells obtained from the femurs. Five specimens per group were examined.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
In the dose-finding test (62.5, 125, 250, 500 or 1000 m/kg bw, p.o.), mortalities were in 3/3 (dead mice/mice treated) at 500 and 1000 mg/kg bw in males, and in 1/3 at 250 mg/kg bw and 3/3 at 500 and 1000 mg/kg bw in females. There was no difference between sexes in mortality in the dosefinding test.

RESULTS OF DEFINITIVE STUDY
In the main test (micronucleus assay), this chemical showed no induction of micronuclei in born marrow polychromatic erythrocytes. The results of micronucleus assay were negative overall.

Dose (mg/kg bw) 0 62.5 125 250
No. of animals examined 5 5 5 5
Frequency of MNPCE (%) Mean 0.18 0.27 0.22 0.29
SD 0.08 0.10 0.04 0.09
Range of MNPCE/2000PCE 2-6 3-8 3-5 3-8
Ration of PCE(%) Mean 57.6 54.6 54.8 48.7
SD 5.8 2.1 9.8 7.9

Note: MNPCE: Micronucleated polychromatic erythrocyte
PCE : Polychromatic erythrocyte

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
An in vivo micronucleus test of 2-naphthol was performed with bone marrow cells of male BDF1 mice. 2-Naphthol did not induce micronuclei in the bone marrow cells at up to 250 mg/kg.