Slags, steelmaking, vanadium

Genetic toxicity: in vivo

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

Study period:

no data available

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Reasonably well descrtibed study. No GLP is reported.

Data source

Reference

Reference Type:

publication

Title:

Evaluation of genotoxicity of oral exposure to tetravalent vanadium in vivo.

Author:

Villani, P.; et al.

Year:

2007

Bibliographic source:

Toxicology letters, 170, 11-8.

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

GLP compliance:

no

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

VOSO4*5H2O

IUPAC Name:

VOSO4*5H2O

Constituent 2

Reference substance name:

123334-20-3

Cas Number:

123334-20-3

IUPAC Name:

123334-20-3

Details on test material:

- Name of test material (as cited in study report): Vanadyl sulphate hydrate
- Physical state: solid
- Analytical purity: 99.99%
No further details are given.

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan s.r.l. (Italy)
- Assigned to test groups randomly: yes
- Diet: ad libitum; laboratory rodent diet
- Water: ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 55 +/- 15
- Photoperiod: 12 hours dark/light cycle
No further details are given.

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

- Vehicle(s)/solvent(s) used: distilled water
No further details are reported.

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Tap water was used to dilute VOSO4 stock solutions and administered as such to control animals.

DIET PREPARATION
not applicable

Duration of treatment / exposure:

5 weeks

Frequency of treatment:

daily

Post exposure period:

no data

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
2 mg/L
Basis:
nominal in water

Doses / concentrations 2

Remarks:

Doses / Concentrations:
10 mg/L
Basis:
nominal in water

Doses / concentrations 3

Remarks:

Doses / Concentrations:
100 mg/L
Basis:
nominal in water

Doses / concentrations 4

Remarks:

Doses / Concentrations:
500 mg/L
Basis:
nominal in water

Doses / concentrations 5

Remarks:

Doses / Concentrations:
1000 mg/L
Basis:
nominal in water

No. of animals per sex per dose:

8 to 10 male mice were randomly assigned to each treatment group.

Control animals:

yes, concurrent vehicle

Positive control(s):

methylmethanesulfonate
- Doses / concentrations: 80 mg/kg body weight
No further details are given.

Examinations

Tissues and cell types examined:

bone marrow

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: preliminary test results

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): no further details

DETAILS OF SLIDE PREPARATION: Bone marrow cells were obtained by flushing both femours with phosphate buffer saline (PBS). After centrifugation and resuspension in PBS, the cell suspension was used for micronucleus assay.
Some drops of bone marrow cell suspension were spread on slides. For each animal 4 slides were prepared. Air-dried smears were then fixed in absolute methanol at room temperature for 5 minutes and stained with 5% solution of Giemsa in 0.01M phosphate buffer at pH 6.8 for 20 minutes to differentiate bone marrow polychromatic (PCE) from normochromatic erythrocytes (NCE).

METHOD OF ANALYSIS: Slides were coded and blind scored using a brightfield microscope. In the first experiment the frequency of micronucleated PCEs was evaluated analysing 2000 cells/animal (1000 cels each of two scorers); 1000 cells/animal were analysed in the positive control group.

OTHER: To assess bone marrow toxicity, the percentage of PCEs was evaluated over 1000 total erythrocytes (PCEs + NCEs).

Evaluation criteria:

No details are reported.

Statistics:

Means of different experimental groups were compared by two-tailed Student's t-test. The limit of statistical significance was set at p=0.05.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Remarks:

No increase in the incidence of MnPCEs was observed in the mice treated with doses from 10 to 1000 mg/L.

Toxicity:

no effects

Remarks:

No treatment related changes in the PCE/NCE ratio.

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
No details are reported, but the top dose was selected as maximum tolerated dose on the basis of the results of a preliminary range-finding experiment and of literature data (ciranni et al. 1995).

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): No increase in the incidence of micronucleated polychromatic erythrocyte (MnPCEs) was observed in bone marrow cells of mice treated with vanadyl sulphate in a range of doses from 10 to 1000 mg/L. The negative result obtained in the first experiment was confirmed in the second experiment.
- Ratio of PCE/NCE (for Micronucleus assay): The determination of the PCE/NCE ratio did not show dose-related deviations in this parameter indicating bone marrow toxicity in treated mice.

General toxicity: Daily water consumption was significantly reduced in the two high dose groups (1000 and 500 µg/L), possibly because of the effect of vanadyl sulphate on the palatability of drinking water. This led to a less than proportional increase in vanadium intake in the high dose groups. Consequently, in the second experiment an increased water consumption was observed in the low dose group (2 mg/L). No significant differences in food consumption were observed among experimental groups. Treatment did not affect body weight gain in the 5 weeks of exposure.

Vanadium distribution: In the first experiment a dose-related, linear increase of vanadium content was observed in bone tissues (R²=0.95 and R²=0.96 in femours and in tibias, respectively). Slightly higher vanadium concentrations were measured in bone in the second experiments at the dose of 10 mg/L: however, when data from the two experiments were compared by t-test, no statistical significant differences at 0.05 level were observed.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Under the given test conditions reported, vanadyl sulphate pentahydrate is not mutagenic in the bone marrow micronucleus assay.

Executive summary:

In this reference, the genotoxic effects induced in vivo by subacute oral exposure to vanadyl sulphate (VOSO₄) were investigated. To this aim male CD1 mice were administered with VOSO₄ in drinking water over the dose range 2 -1000 mg/L for 5 weeks. At the end of treatment, micronuclei in bone marrow polychromatic erythrocytes were determined. Tissue distribution of vandaium at sacrifice was determined by atomic absorption spectrometry.

The analysis of micronuclei did not reveal treatment related effects. Under the given test conditions reported, vanadyl sulphate pentahydrate is not mutagenic in the bone marrow micronucleus assay.