4-aminophenol

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:

experimental study

Adequacy of study:

key study

Study period:

2006/08/31-2007/10/04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study under GLP condition

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

4-aminophenol

EC Number:

204-616-2

EC Name:

4-aminophenol

Cas Number:

123-30-8

Molecular formula:

C6H7NO

IUPAC Name:

4-aminophenol

Details on test material:

- Physical state: slightly brown crystalline powder
- Analytical purity: 99.9%
- Lot/batch No.: LTQ5219 (Wako Pure Chemical Industries, Ltd.)
- Storage condition of test material: in the cool and dark space(3 - 7℃)
:

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc.
- Age at study initiation: 8 weeks old
- Weight at study initiation: Males: 32.3 - 35.9 g
- Housing: Animals were individually housed in plastic cage.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 8days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 25 ℃
- Humidity (%): 42 - 59%
- Air changes (per hr): 10 - 15 times/hr
- Photoperiod (hrs dark / hrs light): 12 hrs dark /12 hrs light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: 0.5 %CMC (carboxymethyl cellulose)-Na

Duration of treatment / exposure:

1 day

Frequency of treatment:

once

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0, 125, 250, 500 mg/kg
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:

Basis:

No. of animals per sex per dose:

6 males/dose

Control animals:

yes, concurrent vehicle

Positive control(s):

Mitomycin C
- Route of administration: i.p.
- Doses / concentrations: 1 mg/kg bw (0.1 mg/ml)

Examinations

Statistics:

Statistical analyses were conducted by　Kastenbaum & Bowman's statistical table, Cochran-Amitage test, student's t-test

Results and discussion

Test results

Sex:

male

Genotoxicity:

positive

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 0, 250, 500, 1000, 2000 mg/kg
- Toxicological findings in test animals:
Mortality: 1000 mg/kg (Male:8/9, Female:7/9), 2000 mg/kg (Male:8/9, Female:7/9)
Clinical sign: Orange brown urine(male/female: >=250 mg/kg), Cyanosis(male: 1000 mg/kg, female: 500, 1000, 2000 mg/kg)
Body weight changes: Decreased body weight or inhibition of body weight gain (male: 250, 500 mg/kg, female: 250, 500, 1000, 2000mg/kg)
- Induction of micronuclei:
Examination periods: at a 24, 48 and 72 h after administration.
The frequency of micronucleated polychromatic erythrocytes was significantly increased in males and females at a 24 h after administration.
- Ratio of PCE/NCE:
Inhibition of bone marrow cell proliferation was observed at a dose of 500 mg/kg at a 24 and 48h after administration.


RESULTS OF DEFINITIVE STUDY (See Table1)
- Induction of micronuclei:
The frequency of micronucleated polychromatic erythrocytes was significantly increased in males at a dose of 125 mg/kg and above.
- Ratio of PCE/NCE:
Examination periods: at a 24h after administration.
Inhibition of bone marrow cell proliferation was observed at a dose of 125 mg/kg and above under the test conditions.

Any other information on results incl. tables

Table 1. Observation of bone marrow smears (about 24 hours after administration)

Group	Animal No.	MNPCE/PCE (%)	PCE/ERY (%)
Vehicle control	1001	1 (0.05)	89 (44.5)
	1002	3 (0.15)	112 (56.0)
	1003	1 (0.05)	112 (56.0)
	1004	3 (0.15)	143 (71.5)
	1005	2 (0.10)	110 (55.0)
	1006	2 (0.10)	120 (60.0)
	Mean ± S.D.(%)	2 ± 1	114 ± 17
	%(Mean ± S.D.)	0.10 ± 0.04	57.2 ± 8.7
125 mg/kg	2001	24 (1.20)	71 (35.5)
	2002	23 (1.15)	109 (54.5)
	2003	25 (1.25)	62 (31.0)
	2004	14 (0.70)	109 (54.5)
	2005	23 (1.15)	96 (48.0)
	2006	21 (1.05)	80 (40.0)
	Mean ± S.D.(%)	22 ± 4	88 ± 20
	%(Mean ± S.D.)	1.08 ± 0.20a),b)	43.9 ± 9.9*c)
250 mg/kg	3001	19 (0.95)	79 (39.5)
	3002	21 (1.05)	89 (44.5)
	3003	29 (1.45)	79 (39.5)
	3004	34 (1.70)	106 (53.0)
	3005	22 (1.10)	59 (29.5)
	3006	12 (0.60)	52 (26.0)
	Mean ± S.D.(%)	23 ± 8	77 ± 20
	%(Mean ± S.D.)	1.140 ± .39a),b)	38.7 ± 9.9**c)
500 mg/kg	4001	25 (1.25)	79 (39.5)
	4002	20 (1.00)	65 (32.5)
	4003	24 (1.20)	61 (30.5)
	4004	24 (1.20)	75 (37.5)
	4005	18 (0.90)	66 (33.0)
	4006	21 (1.05)	59 (29.5)
	Mean ± S.D.(%)	22 ± 3	68 ± 8
	%(Mean ± S.D.)	1.10 ± 0.14a),b)	33.8 ± 3.9**c)
Positive control  (Mytomycin C: 1mg/kg)	5001	52 (2.60)	84 (42.0)
	5002	52 (2.60)	100 (50.0)
	5003	17 (0.85)	100 (50.0)
	5004	55 (2.75)	102 (51.0)
	5005	37 (1.85)	114 (57.0)
	5006	16 (0.80)	84 (42.0)
	Mean ± S.D.(%)	38 ± 18	97 ± 12
	%(Mean ± S.D.)	1.91 ± 0.90a)	48.7 ± 5.8

MNPCE: Micronucleated polychromatic erythrocytes

PCE: Polychromatic erythrocytes

ERY: Erythrocytes

a): Statistically significant increase from the vehicle control value (Kastenbaum & Bowman's statistical table, P<0.05)

b): Dose-dependency by Cochran-Amitage test, P<0.01

c): Statisyically significant difference from the vehicle control value (student's t-test, *: P<0.05; **: P<0.01)

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): positive

Executive summary:

4-aminophenol was administeed orall at doses of 125, 250 and 500 mg/kg and at 24 hours after the administration, bone marrow smear specimens were prepared. Sodium CMC aqueous solution of 0.5% w/v% and 1 mg/kg of mitomycin C were used for a negative convrol and a positive control, respectively.

The occurrence frequency of immature erthrocyes having a micronucleus increased was statistically significant in the groups administered with the test compound compared to the negative control group and was also dose-dependent. Additionally, the percentage of immature erythrocytes per 200 erythrocytes was significnatly decreased in the test article groups compared to the negative control group which was considered to be caused by the test article causing suppressive effects at these doses on bone marrow cell growth. The occurrence frequency of immature erythrocytes having a micronucleus in the negtive and positive controls was within the range of the the historical background of the laboratory, indicating the validity of the test result.

Based on these data, 4 -aminophenol was judged capable of inducing chromosomal aberrations in vivo in bone marrow cells of Crlj:CD1(ICR)(SPF) strain mice under the conditions in this study.