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Toxicological information

Genetic toxicity: in vivo

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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable publication which meets basic scientific principles

Data source

Reference
Reference Type:
publication
Title:
Evaluation of the rodent micronucleus assay in the screening of IARC carcinogens (groups 1, 2A and 2B). The summary report of the 6th collaborative study by CSGMT/JEMS MMS
Author:
Morita T, et al.
Year:
1997
Bibliographic source:
Mutat Res 389: pp. 3-122

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
not specified
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
no data

Test animals

Species:
mouse
Strain:
other: ddY
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 8 to 10 weeks
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

Administration / exposure

Route of administration:
intraperitoneal
Vehicle:
- Vehicle(s)/solvent(s) used: olive oil
Duration of treatment / exposure:
0-72 hours
Frequency of treatment:
1 to 2 treatments
Post exposure period:
24 hour to 72 hours
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 50, 100, 150, 200, 300 mg/kg body weight
Basis:
other: nominal dose
No. of animals per sex per dose:
6 male mice per dose for group 1 (one treatment and analysis of bone marrow)
5 male mice per dose for group 2 (two treamtents at 24 hour interval and analysis of peripheral blood)
5 male mice per dose for group 2 (wo treamtents at 24 hour interval and analysis of bone marrow)
Control animals:
yes, concurrent no treatment
yes, concurrent vehicle
Positive control(s):
mitomycin C
- Route of administration: i.p.
- Doses / concentrations: once 0.5 mg/kg b.w.

Examinations

Tissues and cell types examined:
Both bone marrow polychromatic erythrocytes (PEC) and peripheral blood reticulocytes (RET) were used for analysis. Micronucleated PET and RET frequencies were based on the observation of at least 1000 PET or RET per animal.
Statistics:
Increase in micronucleus frequency was evaluated against the concurrent negative control using a conditional binominal test. Dose-response relationship was evaluated using the Cochran-Armitage trend test. When both tests were significant the test was declared positive. If neither step showed significance the data was judged negative, and all other cases were called inconclusive. Biological significance was also evaluated by an expert committee.

Results and discussion

Test results
Sex:
male
Genotoxicity:
positive
Toxicity:
yes
Remarks:
maximum tolerance dose: 200mg/kg
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes

Any other information on results incl. tables

Dose dependent increase in MN frequencies in bone marrow and peripheral blood.

      % of MNPCE or MNRET (after the final treatment)
tissue number of treamtent dose (mg/kg b.w.) 0h 24h 48h 72h
      mean ± SD mean ± SD p mean ± SD p mean ± SD p
bone marrow 1 0   0.22 ± 0.12          
  50   0.17 ± 0.12 0.798  
  100   0.28 ± 0.18 0.292  
  200   1.40 ± 0.73 0.000  
  300   1.00* 0.000  
          (0.000)        
peripheral blood 2 50 0.26 ± 0.13 0.40 ± 0.29 0.148 0.46 ± 0.28 0.068 0.22 ± 0.15 0.729
  100 0.22 ± 0.23 0.70 ± 0.21 0.000 0.70 ± 0.25 0.000 0.26 ± 0.15 0.419
  150 0.14 ± 0.13 1.14 ± 0.50 0.000 0.98 ± 0.32 0.000 0.74 ± 0.44 0.000
      (0.000) (0.000) (0.000)
bone marrow 2 0   0.14 ± 0.05   0.16 ± 0.05      
  50   0.20 ± 0.23 0.315 0.14 ± 0.09 0.696
  100   0.32 ± 0.08 0.047 0.08 ± 0.05** 0.930
  200   0.70 ± 0.38 0.000 0.40 ± 0.23 0.018
          (0.000)   (0.015)    

*: 4 dead

**: 1 dead

MNPCE: Micronucleated polychromatic erythrocytes

MNRET: Micronucleated reticulocytes

p: p value of pairwise comparisons and that of the Cochran-Amitage trend test in parentheses.

Applicant's summary and conclusion