Vanadium dioxide

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not specified

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

no data available

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1997-07-21

Deviations:

not specified

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Target gene:

not applicable

Species / strain / cell type:

S. typhimurium TA 97

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 102

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

TA102, TA1535 and TA 97: 0, 0.03, 0.1, 0.3, 1.0, 3.0, 6.0, 10.0 and 33.0 µg/plate
TA100 and TA 98: 0, 0.1, 0.3, 1.0, 3.0, 6.0, 10.0, 33.0, 100.0 and 333.0 µg/plate

Vehicle / solvent:

No vehicle is reported, but in the results (summary table) of the reference an evidence is given that a vehicle was used: "0 μg/plate was the solvent control."

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

mitomycin C

other: 4-nitro-o-phenylenediamine & 2-aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar; preincubation

DURATION
- Preincubation period: 20 minutes at 37°C
- Exposure duration: 48 hours at 37°C

NUMBER OF REPLICATIONS: Each trial consisted of triplicate plates.

DETERMINATION OF CYTOTOXICITY
- Method: no data, but the high dose concentration was limited by toxicity.

OTHER EXAMINATIONS:
no other examinations performed

Evaluation criteria:

In this assay, a positive response is defined as a reproducible, dose-related increase in histidine-independent (revertant) colonies in any one strain/activation combination.
An equivocal response is defined as an increase in revertants that is not dose related, is not reproducible, or is not of sufficient magnitude to support a determination of mutagenicity.
A negative response is obtained when no increase in revertant colonies is observed following chemical treatment.
There is no minimum percentage or fold increase required for a chemical to be judged positive or weakly positive.

Statistics:

not mandatory for this test system

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not specified

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

not specified

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

not specified

Additional information on results:

No details are reported.

Conclusions:

Under the test conditions reported the test substance was determined to be negative mutagenic in strains TA97, TA98, TA100, TA102 and TA1535 with and without S9.

Executive summary:

The genetic toxicity of vanadium pentoxide was assessed by testing the ability of the chemical to induce mutations in various strains of Salmonella typhimurium. Vanadium pentoxide was not mutagenic in Salmonella typhimurium strain TA97, TA98, TA100, TA102, or TA1535, with or without induced rat or hamster liver S9 enzymes.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

1997-07-21

Deviations:

not specified

GLP compliance:

yes

Type of assay:

mammalian erythrocyte micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

Divanadium pentaoxide

EC Number:

215-239-8

EC Name:

Divanadium pentaoxide

Cas Number:

1314-62-1

Molecular formula:

V2O5

IUPAC Name:

divanadium pentaoxide

Constituent 2

Reference substance name:

Vanadium pentaoxide

IUPAC Name:

Vanadium pentaoxide

Details on test material:

- Name of test material (as cited in study report): vanadium pentoxide
- Physical state: solid, orange, crystalline
- Analytical purity: ~99%
- Impurities (identity and concentrations): Spark source mass spectrometry indicated vanadium as the major component; the principal impurities were barium (170 ppm), iron (110 ppm), calcium (440 ppm), potassium (550 ppm), sulfur (270 ppm), silicon and sodium (approximately 1,100 ppm each), aluminum (260 ppm), and magnesium (340 ppm). The total concentration of all other impurities was 565 ppm.
- Composition of test material, percentage of components:
- Lot/batch No.: 1210490 and 1210140
No further details are given.

Test animals

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Mice were obtained from Taconic Farms, Inc. (Germantown, NY).
- Age at study initiation: 6 or 7 weeks old
- Weight at study initiation: range of mean body weights in the exposure groups: 25-26 g (males) and 20-21 g (females)
- Assigned to test groups randomly: yes
- Housing: individually
- Diet: ad libitum; except during exposure periods
- Water: ad libitum
- Acclimation period: 10 or 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 23.9 +/- ca. 2
- Humidity (%): 55 +/- 15
- Air changes: 15/hour
- Photoperiod: 12 hours dark/light cycle

Administration / exposure

Route of administration:

inhalation: aerosol

Vehicle:

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

Details on exposure:

TYPE OF INHALATION EXPOSURE: whole body

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- For the 3-month studies, vanadium pentoxide aerosol generation was based on the principle of pneumatic dispersion and consisted of two major components: a screw feeder (Model 310, Accurate, White Water, WI) that metered vanadium pentoxide powder at a constant rate and a Jet-O-Mizer jetmill (Fluid Energy Corp., Harfield, PA) that used compressed air to disperse the metered powder and form the aerosol.
- Aerosol leaving the jetmill passed through a one-stage impactor and a vertical elutriator to eliminate or deagglomerate the large particles before entering a plenum and manifold distribution system. The aerosol delivery system consisted of three holding chambers that diluted the aerosol in three stages. A metered amount of diluted aerosol was removed and mixed with conditioned air at the inlet to each exposure chamber to achieve the appropriate exposure concentration. The electrical charge buildup on the aerosol particles was neutralised by mixing the aerosol with high concentrations of bipolar ions, which were generated using a Pulse Gun (Static Control Services, Palm Springs, CA) air nozzle. A transvector air pump was installed at the aerosol inlet to each exposure chamber to provide additional control of the aerosol flow rate and improve stability of the chamber concentration.
- The stainless-steel inhalation exposure chambers (Lab Products, Inc., Maywood NJ), were designed so that uniform aerosol concentrations could be maintained throughout the chambers when catch pans were in place. The total active mixing volume of each chamber was 1.7 m³.

CHAMBER ATMOSPHERE CHARACTERISATION
- The particle size distribution in each chamber was determined prior to the start of all studies, during the first week and monthly thereafter.
- A 10-stage Quartz Crystal Microbalance-based cascade impactor was used to separate the aerosol particles into sequential size ranges; the mass median aerodynamic diameter was calculated from the corresponding mass fraction of particles at each stage.

OTHER
- The uniformity of aerosol concentration in the inhalation exposure chambers without animals was evaluated before each of the studies began; concentration uniformity with animals present in the chambers was also measured. Minor excursions in chamber uniformity values were observed in one or more exposure chambers, but these excursions had no impact on the studies.
- The stability of vanadium pentoxide in the exposure system was tested with XRD analysis. XRD analyses indicated no detectable build-up of degradation products at a detection limit of approximately 1%.

Duration of treatment / exposure:

3 months

Frequency of treatment:

6 hours plus T90 (15 minutes) per day, 5 days per week

Post exposure period:

1 day

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

1 mg/m³ air (nominal)

Doses / concentrations 2

Dose / conc.:

2 mg/m³ air (nominal)

Doses / concentrations 3

Dose / conc.:

3 mg/m³ air (nominal)

Doses / concentrations 4

Dose / conc.:

8 mg/m³ air (nominal)

Doses / concentrations 5

Dose / conc.:

16 mg/m³ air (nominal)

No. of animals per sex per dose:

Groups of 10 male and 10 female mice were exposed to vanadium pentoxide.

Control animals:

yes

Positive control(s):

no data

Examinations

Tissues and cell types examined:

peripheral blood samples were obtained from male and female mice

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):

DETAILS OF SLIDE PREPARATION: Smears were immediately prepared and fixed in absolute methanol. The methanol-fixed slides were stained with acridine orange and coded.

METHOD OF ANALYSIS: Slides were scanned to determine the frequency of micronuclei in 2000 normochromatic erythrocytes (NCEs) in each of nine or ten animals per exposure group.

OTHER: In addition, the ratio of polychromatic erythrocytes (PCEs) to NCEs among 1000 total erythrocytes was determined as a measure of bone marrow toxicity.

Evaluation criteria:

Statistical as well as biological factors are considered. For an individual assay, the statistical procedure for data analysis has been described in the preceding protocol. There have been instances, however, in which multiple aliquots of a chemical were tested in the same assay, and different results were obtained among aliquots and/or among laboratories. Results from more than one aliquot or from more than one laboratory are not simply combined into an overall result. Rather, all the data are critically evaluated, particularly with regard to pertinent protocol variations, in determining the weight of evidence for an overall conclusion of chemical activity in an assay.

Statistics:

The results were tabulated as the mean of the pooled results from all animals within a treatment group plus or minus the standard error of the mean. The frequency of micronucleated cells among NCEs was analyzed by a statistical software package that tested for increasing trend over exposure groups with a one-tailed Cochran-Armitage trend test, followed by pairwise comparisons between each exposed group and the control group (ILS, 1990). In the presence of excess binomial variation, as detected by a binomial dispersion test, the binomial variance of the Cochran-Armitage test was adjusted upward in proportion to the excess variation. In the micronucleus test, an individual trial is considered positive if the trend test P value is less than or equal to 0.025 or if the P value for any single exposed group is less than or equal to 0.025 divided by the number of exposed groups.

Results and discussion

Test results

Sex:

male/female

Genotoxicity:

negative

Remarks:

No increase in the frequency of micronucleated NCEs was seen in peripheral blood samples from male or female mice exposed to vanadium pentoxide for 3 months by inhalation.

Toxicity:

no effects

Remarks:

Chemical exposure had no effect on the ratio of PCEs to NCEs in peripheral blood indicating no toxicity to the bone marrow by vanadium pentoxide.

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

not specified

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: Based on decreased survival in the 32 mg/m3 males and body weight decreases in 32 mg/m3 males and females, an exposure concentration of 32 mg/m3 was considered too high for use in a 3-month study. Therefore, the exposure concentrations selected for the 3-month inhalation study in rats were 0, 1, 2, 4, 8, and 16 mg/m3.

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): No increase in the frequency of micronucleated NCEs was seen in peripheral blood samples from male or female mice exposed to vanadium pentoxide for 3 months by inhalation.
- Ratio of PCE/NCE (for Micronucleus assay): Chemical exposure had no effect on the ratio of PCEs to NCEs in peripheral blood (data not presented), indicating no toxicity to the bone marrow by vanadium pentoxide.

Applicant's summary and conclusion

Conclusions:

Vanadium pentoxide, administered for 3 months by inhalation to male and female mice, did not increase the frequency of micronucleated normochromatic erythrocytes in peripheral blood.

The genetic toxicity of vanadium pentoxide was assessed by testing the ability of the chemical to induce an increases in the frequency of micronucleated erythrocytes in mouse peripheral blood. Mice were exposed 90 days to an vanadium pentaoxide aerosol by inhalation before blood was sampled and prepared for analysis.
Vanadium pentoxide, administered to male and female mice, did not increase the frequency of micronucleated normochromatic erythrocytes in peripheral blood.