Registration Dossier

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:
2003-03-19 to 2003-02-07
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline study, GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
, adopted on 1997-07-21
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.11 (Mutagenicity - In Vivo Mammalian Bone-Marrow Chromosome Aberration Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of assay:
micronucleus assay

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
444-860-9
EC Name:
-
Cas Number:
474510-57-1
Molecular formula:
C21 H24 O4
IUPAC Name:
2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl) benzyl) phenyl)-2-methylpropan-1-one

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: RCC Ltd., Biotechnology and Animal Breeding Division, CH-4414 Rossdorf, Switzerland
- Age at start of acclimization: 8-10 weeks
- Weight at study initiation: males mean value 33.39 g and females mean value 27.13 g
- Assigned to test groups randomly: yes
- Fasting period before study: Approximately 18 hours before treatment the animals received no food but water ad
libitum
- Housing: Individuelly in Makrolon type- 1 cages
- Diet: pelleted standard diet, ad libitum (ALTROMIN 1324, D-32791 Lage/Lippe, Germany)
- Water: tap water, ad libitum, (Gemeindewerke, D-64380 Rossdorf, Germany)
- Acclimation period: minimum 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 3 "C
- Humidity (%): 22 - 70 %
- Photoperiod: artificial light 6.00 a.m. - 6.00 p.m.

IN-LIFE DATES: From: To: 2003-01-04 until 2003-02-07

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Not detailed

Duration of treatment / exposure:
Single dose
Frequency of treatment:
Once
Post exposure period:
Sampling of the bone marrow was done 24 hours after treatment (to animals administered with 500, 1000, and 2000 mg/kg bw.of the test item) and 48 hours after treatment (to animals administered with 2000 mg/kg bw)
acute toxic symptoms were examined at intervals of around 1 h, 2-4 h, 6 h, 24 h, 30 h, and 48 h after administration of the test item.
Doses / concentrations
Remarks:
Doses / Concentrations:
500, 1000, 2000 mg/kg bw
Basis:
nominal conc.
No. of animals per sex per dose:
10 animals (5 males, 5 females) per dose
Control animals:
yes, concurrent vehicle
Positive control(s):
Cyclophosphamide - 40 mg/kg b.w

Examinations

Tissues and cell types examined:
Erythrocyres from the bone marrow
Details of tissue and slide preparation:
- The femora were removed, the epiphyses were cut off and the marrow was flushed out with fetal calf serum, using a syringe. The cell suspension was centrifuged at 1500 rpm (390 x g) for 10 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-Grunwald. Cover slips were mounted with EUKITT. At least one slide was made from each bone marrow sample
- Evaluation of the slides was performed using NIKON microscopes with 100 x oil immersion objectives. At least 2000 polychromatic erythrocytes (PCE) were analysed per animal for micronuclei. To describe a cytotoxic effect the ratio between polychromatic and total erythrocytes was determined in the same sample and expressed in polychromatic erythrocytes per 2000 erythrocytes. The analysis was performed with coded slides.
Evaluation criteria:
A test item was classified as mutagenic if it induced either a dose-related increase or a clear increase in the number of micronucleated polychromatic erythrocytes in a single dose group. Statistical methods (nonparametric Mann-Whitney test were used as an aid in evaluating the results. However, the primary point of consideration is the biological relevance of the results.
A test item that fails to produce a biological relevant increase in the number of micronucleated polychromatic erythrocytes is considered non-mutagenic in this system.
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 examined
Positive controls validity:
valid
Additional information on results:
- After treatment with the test item the number of PCEs was not substantially decreased as compared to the mean value of PCEs of the vehicle control thus indicating that the test item did not exert any cytotoxic effects in the bone marrow
- In comparison to the corresponding vehicle controls there was no biologically relevant or statistically significant enhancement in the frequency of the detected micronuclei at any preparation interval after administration of the test item and with any dose level used
- Cyclophosphamide (positive control) administered orally was used as positive control which showed a substantial increase of induced micronucleus frequency.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative