Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
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: Comparable to guideline study with acceptable restrictions Read-across is based on the great structural similarity between aniline and N-methylaniline

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1991

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
Deviations:
not applicable
Principles of method if other than guideline:
In order to investigate whether the species specific carcinogenicity is reflected in the results of the bone marrow micronucleus tests after oral dosing, aniline hydrochloride was assayed for potential clastogenicity in the mouse micronucleus test after oral administration to male CRH mice. A group of animals dosed i.p. with aniline hydrochloride was included for comparative purposes.
GLP compliance:
not specified
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Aniline hydrochloride
- Analytical purity: > 99%

Test animals

Species:
mouse
Strain:
other: CRH
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Rodent Breeding Unit, Glaxo Group Research Ltd
- Age at study initiation: 7-8 wks old
- Diet (e.g. ad libitum): no.l Special Diets Services diet
- Water (e.g. ad libitum): ad libitum

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: [sterile water]
Duration of treatment / exposure:
24 or 48 hr
Frequency of treatment:
Single dose
Post exposure period:
None
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
380 mg/kg
Basis:
nominal conc.
i.p. route
Remarks:
Doses / Concentrations:
400, 500 and 1000 mg/kg
Basis:
nominal conc.
oral route
No. of animals per sex per dose:
4 to 8 animals/group
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide
- Route of administration: oral

Examinations

Tissues and cell types examined:
Polychromatic erythrocytes
Details of tissue and slide preparation:
DETAILS OF SLIDE PREPARATION: Slides were coded prior to analysis and stained using the May-Grunwald/Giemsa technique. Some additional slides were also stained using a Feulgen-Iight green staining technique for DNA

METHOD OF ANALYSIS: For each animal, 2000 polychromatic erythrocytes (PE) were analysed for the presence of micronuclei. Five hundred erythrocytes/animal were scored to determine the percentage of PE among all erythrocytes.
Statistics:
The likelihood ratio test was used to analyse the data from the two i.p. dosing experiments. For the oral dosing experiments statistical analyses of micronucleus frequencies were performed using the non-parametric Dunn's multiple comparison test, with the exception of the repeat test where the Wilcoxon two-sample test was employed due to the use of only one dose group.

Results and discussion

Test results
Sex:
male
Genotoxicity:
positive
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
Aniline was positive in the standard (single dose) mouse bone marrow micronucleus test, 24 h after oral dosing, but only at the high dose level of 1000 mg/kg

Any other information on results incl. tables

Table 1. Results of micronucleus test in CRH mice with a single dose of aniline

 Treatment  Dose (mg/kg)  Sex  Sample time (h)  No. of animals  MNPE/1000 PE individual animal values MNPE/1000PE (mean ± SD)  PE(%)(± SD) 
Oral dosing (first study)                  
Water 10 ml/kg  M 24 7 1,0.5,0,0.5,0,0.5,0.5 04 ± 0.3 44 ± 8
 Aniline* 4005001000  M 242424 778  2,1.5,0,1,3,0,00.5,2.5,1,2,0,1,218.5,15,4.5,3,2.5,2.5,4,12  1.1 ± 1.21.3 ± 0.96.1 ± 6.b 37 ± 530 ± 849 ± 17
 Cyclophosphamide 30  M 24 4 9,11,18,6.5 11.1 ± 4.9c 57 ± 15
 Water 10 ml/kg  M 48 7 0,0,1,0.5,2,0,0 0.5 ± 0.8 49 ± 12
 Aniline* 4005001000  M 484848  777 1,0,1,0.5,0,0.5,0.50.5,0,0.5,0,0,0,1.51,0,1,1,1,1,2 0.5 ± 0.40.4 ± 0.61.0 ± 0.6 50 ± 849 ± 1039 ± 7
 Oral dosing (repeat study)              
 Water 10 ml/kg  M 24 7 0,1.5,0.5,0,1,0.5,1.5 0.7 ± 0.6 42 ± 6
 Aniline* 1000  M 24 7 3,2.5,2,6,10,15,0.5 5 6 ± 5.2b  38 ± 6
 Cyclophosphamide 30  M 24 2 8,6.5 7.3c 43
 I.p. dosing (first study)                     
 0.9% NaCl 5 ml/kg  M  24  4 0,0.5,0.5,0 0.3 ± 0.3 42 ± 14
 Aniline* 380  M  24  4 1,4 5,3.5,3.5 3.1 ± 1.5b 36 ± 8
 I.p. dosing (repeat study)                   
 0.9% NaCl 5 ml/kg  M  24  8  0.5,0,0,0.5,1,0,1,0.5 0.4 ± 0.4 37 ± 9
 Aniline* 380  M  24  8  2.5,0,1.5,4.5,2.5,3,4.5,2.5 2.6 ± 1.5b 34 ± 12

* Dose levels are expressed as mg/kg free base

b Treatment significantly different from control (P < 0.05).

c Positive control is not included in the statistical analyses.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): positive
The high oral dose of aniline needed for micronucleus induction, the presence of micronuclei with abnormal morphology and the large inter-animal variability found within this group may possibly indicate a more complex mechanism of micronucleus induction than simple clastogenicity.
Given the high resemblance between aniline and N-methylaniline, and their similar physico-chemical properties, the results obtained in this study can be attributed to N-methylaniline.