Frits, chemicals

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Experimental guideline study, available in the peer reviewed literature. Minor restrictions in design and / or reporting but otherwise adequate for assessment.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Test material form:

solid - liquid: suspension

Details on test material:

- Name of test material (as cited in study report): Sodium ortho-vanadate
- Analytical purity: >90%

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 (Udine, Italy)
- Age at study initiation: 5-6 weeks
- Weight at study initiation: approx 14 g (+/- 2.2 g)
- Assigned to test groups randomly: yes
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 °C (+/- 2°C)
- Humidity (%): 55 (+/- 15 )
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

- Vehicle(s)/solvent(s) used: water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Sodium ortho-vanadate was dissolved in distilled water and diluted with tap water to make up the dosing solutions. Tap water was used for the control.

DIET PREPARATION: No data

Duration of treatment / exposure:

5 weeks

Frequency of treatment:

Continous

Post exposure period:

Not applicable

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1500 mg/L
Basis:
nominal in water

Doses / concentrations 2

Remarks:

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

Doses / concentrations 3

Remarks:

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

Doses / concentrations 4

Remarks:

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

Doses / concentrations 5

Remarks:

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

No. of animals per sex per dose:

5 males in each dose in the first experiment and 5 animals at the 0.75 mg/L, 7.5 mg/L, and 75 mg/L in the second experiment.

Control animals:

yes, concurrent vehicle

Positive control(s):

- methylmethanesulfonate (MMS)
- Route of administration: single intra peritoneal injection with MMS 24 h before sacrifice
- Doses / concentrations: 80 mg/kg bw

Examinations

Tissues and cell types examined:

Bone marrow

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: A preliminary range finding experiment was carried out to select the maximum tolerated dose of 1500 mg/L. The first experiment used 7.5 mg/L, 75 mg/L, 750 mg/L, and 1500 mg/L. A second experiment had to be perfomed to clarify the results of the experiment and this was done with 0.75 mg/L, 7.5 mg/L, and 75 mg/L.

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

DETAILS OF SLIDE PREPARATION:
- Bone marrow cells were obtained by flushing both femurs with PBS.
- Drops of bone marrow cells suspension for each animal were spread on four slides.
- Air-dried smears were then fixed in absolute methanol at room temp for 5 min and stained with a 5% solution of Giemsa in 0.01 M phosphate buffer at pH 6.8 for 20 min to differentiate bone marrow polchromatic (PCE) from normochromatic erythrocytes (NCE).


METHOD OF ANALYSIS:
- Slides were coded and blind scored using a brightfield microscope.
- The frequency of micronucleated PCEs (MnPCEs) was evaluated by the analysis of 4000 cells for each animal by two scorers (2000 cells each).
- The vanadium content in the femour and tibia tissue collected was analysed by means of inductively coupled plasma emission spectrophotometry

OTHER:
- The percentage of PCEs among 1000 erythrocytes (PCEs+NCEs) was determined to assess bone marrow toxicity.

Evaluation criteria:

No data

Statistics:

Significance of differences between treated and control groups was determined using one-tail Student's t-test. However, when data for the two experiments were pooled ANOVA was used to rule out heterogeneity between experiments.

Results and discussion

Test results

Sex:

male

Genotoxicity:

positive

Remarks:

At the highest dosed tested (750 mg/L and 1500 mg/L)

Toxicity:

yes

Remarks:

At the highest dose tested (1500 mg/L) one animal died during the 3rd week of treatment. Mild signs of toxicity (viz. lethargy) were observed during the last two weeks of treatment in mice treated with 750 mg/L and 1500 mg/L.

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Not reported

RESULTS OF DEFINITIVE STUDY
- At the end of the 5 week exposure period there was there was no indication of bone marrow toxicity.
- The incidence of micronucleated PCEs was significantly increased in mice treated with the two highest doses (750 mg/L and 1500 m/L).
- There was lower statistical significance in increase micronucleated PCEs observed at the lowest dose of 7.5 mg/L but not 75 mg/L.
- In the repeat clarification experiment no statistical significance deviation in the average incidence of micronucleated PCEs was observed.
- A clearcut positive response was observed in the positve control but no evidence of toxicity to bone marrow cells.

OTHER
- Vanadium concentration increased linearly with administered doe in femurs (r=0.97) and in tibias (r=0.99).

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): positive at the two highest concentrations tested
The study results indicate that vanadium is able to exert significant genotoxic effect in somatic cells in vivo as demonstrated by the results of the induction of micronuclei in bone marrow. However, this effect was only seen at the two highest concentrations (750 mg/L and 1500 mg/L).