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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Study period:
no data available
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Reasonably well descrtibed study. Study was not performed according to GLP. Individual data on MnPCE given.

Data source

Reference
Reference Type:
publication
Title:
Assessment of the in vivo genotoxicity of vanadate: analysis of micronuclei and DNA damage induced in mice by oral exposure.
Author:
Leopardi, P.; et al.
Year:
2005
Bibliographic source:
Toxicology letters, 158, 39-49.

Materials and methods

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

Test material

Constituent 1
Reference substance name:
Trisodium tetraoxovanadate
EC Number:
237-287-9
EC Name:
Trisodium tetraoxovanadate
Cas Number:
13721-39-6
IUPAC Name:
trisodium tetraoxovanadate(3-)
Test material form:
other: solid
Details on test material:
- Name of test material (as cited in study report): Sodium ortho-vanadate
- Molecular formula (if other than submission substance): Na3VO4
- Purity: >90%
- Physical state: solid

Test animals

Species:
mouse
Strain:
CD-1
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Animals were obtained from Harlan, Italy.
- Age at study initiation: 5-6 weeks
- Assigned to test groups randomly: yes
- 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: water
No further details are given.
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Test item was dissolved in distilled water. Tap water was used to dilute Na3VO4 solutions, and administered as such to control animals.

DIET PREPARATION
not applicable
Duration of treatment / exposure:
5 weeks
Frequency of treatment:
daily intake
Post exposure period:
not applicable
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0.75 mg/L
Basis:
nominal in water
Remarks:
Doses / Concentrations:
7.5 mg/L
Basis:
nominal in water
Remarks:
Doses / Concentrations:
75 mg/L
Basis:
nominal in water
Remarks:
Doses / Concentrations:
750 mg/L
Basis:
nominal in water
Remarks:
Doses / Concentrations:
1500 mg/L
Basis:
nominal in water
No. of animals per sex per dose:
5 animals were randomly assigned to each treatment group.
Control animals:
yes
Positive control(s):
methylmethanesulfonate (MMS)
- Route of administration: single intra peritoneal injection 24 hours before sacrifice
- Doses / concentrations: 80 mg/kg body weight

Examinations

Tissues and cell types examined:
bone marrow
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: The top dose was selected as maximum tolerated dose on the basis of the results of a preliminary range-finding experiment.
Two experiments were performed: In the first experiment 0, 7.5, 75, 750, 1500mg/L were tested and in the second experiment concentrations were chosen to calrify the results from the first experiment (0, 0.75, 7.5, 75mg/L).

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): No further details are given.

DETAILS OF SLIDE PREPARATION: Bone marrow cells were obtained by flushing both femurs with PBS. After ecntrifugation 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 bright field microscope. The frequency of micronucleated PCes (MnPCEs) was evaluated by the analysis of 4000 cells for each animal by two scorers (200 cells for each one).
Vanadium content in femur and tibia quantified via ICP-OES.

OTHER: In addition, the percentage of PCEs among 1000 total erythrocytes (PCEs + NCEs) was determined to assess bone marrow toxicity.
Evaluation criteria:
no data
Statistics:
Significance of difference between treated and control group was determined using one-tailed Student's t-test. When data from two experiments were pooled, analysis of variance was applied to rule out heterogenecity between experiments.

Results and discussion

Test results
Sex:
male
Genotoxicity:
positive
Remarks:
A significant increase of MnPCE observed at 750 and 1500mg/L.
Toxicity:
yes
Remarks:
1 animal administrated with the highest concentration of the test item died during the 3rd week of treatment. Mild signs of toxicity were observed during the last 2 weeks of treatment in mice treated with 750 and 1500mg/L.
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.

RESULTS OF DEFINITIVE STUDY
At the end of the 5-week treatment period, no deviation in the PCE percentual, indicative of bone marrow toxicity was observed. The incidence of micronucleated PCEs was significantly (p<0.01) increased in mice treated with the two highest doses. An increase in micronucleated PCEs with lower statistical significance (p<0.05) was also observed in mice treated with the lowest dose (7.5mg/L), but not so in mice receiving a 10-fold higher Na3VO4 concentration in drinking water (75mg/L).
In order to clarify the consistency of the experimental findings, a second expriment was carried out with a lower dose range (0.75, 7.5 and 75mg/L). In the repeated experiment, no statistically significant deviation in the average incidence of micronucleated PCEs was observed, comparing treated and control animals.

A clearcut positive response was produced by the positive control MMS, with no evidence of toxicity to bone marrow cells.

OTHER:
Elemental vanadium (V5+) was determined in all tissues.
Water intake was significantly lower (p<0.01) in mice receiving the two highest concentrations of the test item, possible because of an effect of the compound on water palatability: consequently, animal exposure was less than proportionally increased in the two highest dose groups.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): positive
The test item was considered to be positive mutagenic under the given experimental conditions.
Executive summary:

In an in vivo micronucleus test with bone marrow, mice were treated with sodium ortho vanadate (0, 0.75, 7.5, 75, 750 and 1500mg/L dissolved in water) via the drinking water. The exposure duration was 5 weeks. Control groups (vehicle control and positive) were treated in parallel. After 5 weeks the bone marrow was sampled and prepared for analysis.

No treatment related changes in PCE/NCE ratio were observed. Vanadium content in femur and tibia was quantified via ICP-OES.

A significant increase of MnPCE was observed in the first experiment at 750 and 1500mg/L. No increase of MnPCE observed in the second experiment. Micronucleated reticulocytes were increased at week 3 and 5 in 75, 750mg/L and 0.75, 7.5, 750mg/L groups, respectively.

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