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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant OECD guideline study, available two unpublished reports, no restrictions, fully adequate for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
Qualifier:
according to
Guideline:
EU Method B.11 (Mutagenicity - In Vivo Mammalian Bone-Marrow Chromosome Aberration Test)
GLP compliance:
yes
Type of assay:
chromosome aberration assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Name of test substance: sodium hexafluoroaluminate
Manufacturer: BAYER AG
Batch number: 2
Content: 98.9%
Approved: until September 10, 1997
Appearance: powder
Storage: dry at room temperature ín the dark
Common name: Cryolite (Kryolith synth.)

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles river Limited (Manston Road Margate, UK)
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: 142-146 g
- Housing: 5 or 6 of the same sex in a cage
- Diet: ad libitum, standard quality-controlled laboratory rat food
- Water: ad libitum, tap water

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21±3
- Humidity (%): 55±15
- Photoperiod (hrs dark / hrs light): 12 hours

Administration / exposure

Route of administration:
inhalation: aerosol
Vehicle:
none (unchanged)
Details on exposure:
This cytogenetic test was run within the 13-week inhalation study. Satellite animals (male only) were included for determination of chromosomal aberrations at the end of 13 weeks exposure. Six male rats were held but not exposed during the 13 weeks of exposures, at the end of which time they were dosed intraperitoneally with cyclophosphamide as a positive control.
Duration of treatment / exposure:
13 weeks
Frequency of treatment:
6 hours/day, 5 days/week
Post exposure period:
24 hours
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
5.0 mg/m3
Basis:
other: target concentration
Remarks:
Doses / Concentrations:
4.6 mg/m3
Basis:
analytical conc.
No. of animals per sex per dose:
6 males
Control animals:
yes
Positive control(s):
The animals in the positive contol group were treated with a single intraperitoneal injection of cyclophosphamide at a dosage of 25 mg/kg bw using a standard dose volume of 10 ml/kg bw. The dosing was performed so as to coincide with the time of completion of the 13 week inhalation study.

Examinations

Tissues and cell types examined:
bone marrow (from femurs)
Details of tissue and slide preparation:
Approximately 2.5 hours prior to sacrifice, all satellite animals were treated with colchicine by intraperitoneal injection at a dose level of 4 mg/kg bw to arrest dividing cells at metaphase. Colchicine was formulated on the day of use as a solution in 0.9% saline at a concentration of 0.4 mg/ml.

Six satellite male rats in the negative control and the test substance treated group were sacrificed (by cervical dislocation) 24 hours after completion of treatment. Six male rats dosed-with a single intraperitoneal injection of cyclophosphamide at 25 mg/kg bw in the positive control satellite group were sacrificed 24 hours after dosing.

Both femurs were dissected from each animal. The distal heads were kept intact and as much tissue as possible was removed from the bones. Bone marrow was aspirated with Hanks' balanced salts solution then treated with a hypotonic potassium chloride solution. The cells were fixed and a homogenous cell suspension was prepared. At least four slides were prepared from each animal. Two of these slides from each animal were stained in Giemsa.
Evaluation criteria:
The test was considered positive if, at any of the intervals, there was a biologically relevant increase in the number of metaphases with aberrations excluding gaps and/or the number of metaphases with exchanges. A test was considered negative if there was no such relevant or significant increase.

Results and discussion

Test results
Sex:
male
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
increased inorganic fluoride concentrations in urine, bones, and teeth were evident for rats in exposed to 4.6 mg/m3 cryolite in the 90 days inhalation toxicity study (see repeated dose toxicity) showing systemic exposure to cryolite
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The mitotic indices showed no relevant differences between the treated group and the negative control.

There were no treatment-related variations between the negative control and exposed group with respect to the parameters relevant to assessment of a clastogenic effect (metaphases with aberrations including or excluding gaps and metaphases with exchanges) . None of the parameters were significantly increased.

Applicant's summary and conclusion