Registration Dossier

Toxicological information

Genetic toxicity: in vivo

Currently viewing:

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: see 'Remark'
Remarks:
GLP - Guideline study. According to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): FAT 66'031/B
- Physical state: Yellow solid
- Analytical purity: 88.1%
- Lot/batch No.: BSG ex Pa 34/45
- Expiration date of the lot/batch: 1992
- Stability under test conditions: Pure test article reported to be stable for "years" and stability in water (vehicle) reported to be > 2 hours
- Storage condition of test material: At 4 ºC, protected from light

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL Tierfarm Fullinsdorf
- Age at study initiation: at least 10 weeks
- Weight at study initiation: approx. 30 g
- Assigned to test groups randomly: yes
- Fasting period before study: 18 hours
- Housing: singly housed in Makrolon Type I cages with wire mesh top (EHRET GmbH, D-7830 Emmendingen)
- Diet: Pelleted standard diet (ALTROMIN, D-4937 Lage/Lippe)
- Water: tap water, ad libitum (Gemeindewerke, D-6101 RoBdorf)
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3
- Humidity (%): 25 - 70
- Photoperiod (hrs dark / hrs light): 12h/12h

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: distilled water
Duration of treatment / exposure:
single adiministration
Frequency of treatment:
single administration
Post exposure period:
24, 48 and 72 h
Doses / concentrations
Remarks:
Doses / Concentrations:
5000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
6/sex/group/time point
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide:
- Route of administration: single oral (gavage) dose
- Doses / concentrations: 30 mg/kg bw/day

Examinations

Tissues and cell types examined:
Polychromatic erythrocytes from femurs of all animals
Details of tissue and slide preparation:
TREATMENT AND SAMPLING TIMES:
The animals received the test article once. Sampling of the bone marrow was done at 24, 48 and 72h after treatment.

DETAILS OF SLIDE PREPARATION: The animals were sacrificed by cervical dislocation. The femora were removed, the epiphyses were cut off and the marrow was flushed out with fetal calf serum using a 5 mL syringe. The cell suspension was centrifuged at 1500 rpm for 5 minutes and the supernatant was discarded. A small drop of the resuspended cell pellet was spread on a slide. The smear was air-dried and then stained with May-Gruenwald (MERCK, D-6100 Darmstadt, F.R.G.)/Giemsa (Gurr, BDH Limited Poole, Great Britain). Cover slips were mounted with EUKITT (KINDLER, D-7800 Freiburg F.R.G.). At least one slide was made from each bone marrow sample.

METHOD OF ANALYSIS: 1000 polychromatic erythrocytes (PCE) were analysed per animal for micronuclei. To describe a cytotoxic effect the ratio between polychromatic and normochromatic erythrocytes was determined in same sample and expressed in normochromatic erythrocytes per 1000 the PCEs. The analysis was performed with coded slides. 5 animals/sex/group were evaluated as described. The remaining animal of each test group was evaluated in case an animal had died in its test group spontaneously or due to gavage error.
Evaluation criteria:
A test article is classified as mutagenic if it induces a statistically significant increase in the number of micronucleated polychromatic erythrocytes in at least one of the test points.

A test article producing no statistically significant increase in the number of micronucleated polychromatic erythrocytes at any one of the test points is considered non-mutagenic in this system. This can be confirmed by means of the nonparametric Mann-Whitney test.

However, both biological and statistical significance should be considered together.
Statistics:
nonparametric Mann-Whitney test

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
One of the treated animals expressed slight toxic reactions (denoted as "reduction of spontaneous activity") up to 48 h after exposure.

Any other information on results incl. tables

Results:

Sampling time Test group Polychromatic erythrocytes Normocytes / total amount polychromatic erythrocytes Cells with micronuclei (%)
Dose (mg/kg bw)
24 h vehicle control 10000 8291 0.06
5000 10000 9784 0.05
CPA 10000 8376 0.63
25 h vehicle control 10000 8877 0.07
5000 10000 8941 0.06
72 h vehicle control 10000 7685 0.06
5000 10000 8335 0.13

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
It can be stated that under the experimental conditions reported, the test article did not induce micronuclei as determined by the micronucleus test with bone marrow cells of the mouse. Therefore, the test substance is considered to be non-mutagenic in this micronucleus assay.