Ammonium trioxovanadate

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Well documented study, nevertheless the study is partly compromised by the low group sizes (n=8) so that some results of the study could not be rated as reliable. The relevance of this study is limited due to the testing parameters (not) investigated, and most results of the study were considered reliable with restrictions.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

One year treatment of non-diabetic and streptozotocin-diabetic rats with vanadyl sulphate did not alter blood pressure or haematological indices.

Author:

Dai, S.; McNeill, J.H.

Year:

1994

Bibliographic source:

Pharmacol. Toxicol. 74, 110-115

Reference 2

Reference Type:

publication

Title:

One year treatment of streptozotocin-induced diabetic rats with vanadyl sulphate.

Author:

Dai, S.; et al.

Year:

1994

Bibliographic source:

Pharmacol. Toxicol. 74, 101-109

Reference 3

Reference Type:

publication

Title:

Toxicity studies on one year treatment of non-diabetic and streptozotocin-diabetic rats with vanadyl sulphate.

Author:

Dai, S.; et al.

Year:

1994

Bibliographic source:

Pharmacol. Toxicol. 75, 265-273

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

This short description is restricted to non-diabetic rats. Investigations on the diabetic rats are not considered here. Four groups of non-diabetic male rats received different concentrations of VOSO4 in drinking water for 52 weeks. The low dose group received 500 mg/L for 52 weeks. The mid dose group received 500 mg/L for 1 week and then 750 mg/L for 51 weeks. The high dose group received 500 and 750 mg/L for 1 week each and then 1250 mg/L for further 50 weeks. Subgroups of 3 animals from each of the four groups were followed for further 16 weeks after cessation of VOSO4 treatment. Various parameters were examined and determined.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Vanadium oxide sulphate

EC Number:

248-652-7

EC Name:

Vanadium oxide sulphate

Cas Number:

27774-13-6

IUPAC Name:

oxovanadium(2+) sulfate

Details on test material:

- Name of test material (as cited in study report): Vanadyl sulphate x n hydrate (between 2 and 3 waters of hydration)
- Molecular formula (if other than submission substance): VOSO4 x nH2O (n=2-3)
- Substance type: technical product
- Stability: the solution of this compound in drinking water has a stable chemistry as indicated by a stable blue colour.
- Other: substance was purchased from Fisher Scientific Co. (Fair Lawn, NJ, USA)
No further information stated.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Montreal, Quebec, Canada
- Weight at study initiation: 270-320 g
- Diet (ad libitum): standard laboratory food (Purina rat chow)
- Water: ad libitum: vanadyl sulphate hydrate mixed with tap water

ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12/12
No further information stated.

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
- Vanadyl sulphate hydrate (Fischer Scientific Co., Lair lawn, NJ, USA) was mixed with drinking water.
- Solutions were prepared on alternative days.
No further information stated.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

52 weeks

Frequency of treatment:

continuously (ad libitum in drinking water)

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
500 mg/L for 52 weeks (low dose group)
Basis:
nominal in water

Doses / concentrations 2

Remarks:

Doses / Concentrations:
500 mg/L for 1 week, then 750 mg/L for 51 weeks (mid dose group)
Basis:
nominal in water

Doses / concentrations 3

Remarks:

Doses / Concentrations:
500 mg/L for 1 week, 750 mg/L for 1 week, then 1250 mg/L for 50 weeks (high dose group)
Basis:
nominal in water

No. of animals per sex per dose:

8 male rats per group

Control animals:

yes

Details on study design:

- Rationale for animal assignment: random

Positive control:

no data

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: animals were examined closely for possible occurrance of diarrhoea, cataract formation or deterioration of their general condition.

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: every 3-5 weeks; every 2-3 weeks during post-exposure observation period.

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: measured every 3-5 weeks; every 2-3 weeks during post-exposure observation period.

FOOD EFFICIENCY: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: regularly, every 3-5 weeks; every 2-3 weeks during post-exposure observation period

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: hematocrit, after 3, 6, 9 and 12 months of treatment as well as 3 months after withdrawal. Other paramenters after 52 weeks of exposure and 3 months of withdrawal.
- How many animals: each rat (haematocrit index).
- Parameters checked: hematocrit index of peripheral blood, haemoglobin, erythrocyte count, leukocyte count and composition, platelet count and reticulocyte percentage .

CLINICAL CHEMISTRY: Yes,
- Time schedule for collection of blood: every 3 months during treatment and 16 weeks after vanadyl withdrawal.
- Animals fasted: for 5 hr
- Parameters checked: aspartate aminotransferase, alanine aminotransferase and urea (for liver and kidney function).
- In addition, determination of non-fasting blood glucose (weekly in the first 4 weeks and then once upon every 2-4 weeks), fasting plasma glucose and insulin, plasma trigycerides and cholesterol throughout the exposure time (every 3 months).

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

OTHER:
- Determination of systolic blood pressure, pulse rate after 3, 6, 9 and 12 months of treatment as well as 3 months after withdrawal using tail-cuff method.
- Vanadium levels were determined in the 5-hr fasting plasma samples obtained at the end of the 52 wk-treatment and at weeks 6 and 12 after vanadyl withdrawal.
- V levels were determined in plasma, bone and some of the inner organs after 1 year exposure and after 16 weeks of vanadyl withdrawal

Sacrifice and pathology:

After treatment for 52 weeks most of the rats were terminated for morphological studies with an overdose of halothane followed by decaptation. 8 rats from the exposed groups and 3 rats from the control group were kept and observed for a further period of 16 weeks (without exposure).

GROSS PATHOLOGY: Yes,
- Brain, thymus, lung, heart, liver, spleen, pancreas, adrenal gland, kidney and testis were weighed.

HISTOPATHOLOGY: Yes,
- Brain, thymus, lung, heart, liver, spleen, pancreas, adrenal gland, kidney and testis were examined.

Other examinations:

no

Statistics:

All results were expressed as mean and standard error of the mean. The data were analyzed using repeated measure or one-way ANOVA, as appropriate, followed by the Newman-Keul’s test, if required. The values of haematological indices of the same rats before and after the withdrawal of vanadyl sulphate were compared using an unpaired Student’s t-test. The level of significance was set at P<0.05. The data from the morphological studies are presented as incidence (%) of the specific morphological abnormalities in each organ and were analyzed with the Chi-Square test. The data of plasma levels of AST; ALT and urea, of organ weight/body weight ratio, and of plasma and tissue concentrations of vanadium are shown as mean and standard error of the mean, and were analyzed with two-way or one-way analysis of variance, as appropriate, followed by the Newman-Keul’s test, if required.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

in high dose group

Mortality:

mortality observed, treatment-related

Description (incidence):

in high dose group

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

dose dependent decrease

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

no effects observed

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not specified

Details on results:

Only data on non-diabetic rats are considered. According to the authors, apart from the body weight changes, intakes of VOSO4 and plasma V concentrations, there were no significant differences in all other parameters among the V treatment groups. Therefore, the pooled results of the 3 treatment groups were used.

CLINICAL SIGNS AND MORTALITY
- One animal died in the high dose group for unknown reasons after 18 weeks of treatment.

BODY WEIGHT AND WEIGHT GAIN
- Body weight gain was slightly reduced in the low and mid dose groups indicated by an increasing number of deviations from control values from week 13 onwards reaching occasionally statistical significance.
- Body weight gain was markedly and statistically significantly, at most time points, reduced in the high dose group after week 4.

FOOD CONSUMPTION
- Food intake was not changed by V exposure compared to the controls.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study)
- Water intake was not changed by V exposure compared to the controls.
- Average intakes of VOSO4 were reported to be 34, 54 and 90 mg/kg bw/day (corresponding to 0.16, 0.25 and 0.41 mmol/kg/day).

HAEMATOLOGY
- Haematocrit did not show any differences between treatment and control groups.
- No differences between treatment and control groups were observed with respect to the haematological indices.

CLINICAL CHEMISTRY
- Apart from transient fluctuations, data on clinical chemistry were not changed by the treatment.

ORGAN WEIGHTS
- Relative organ weights of brain, thymus, lung, heart, liver, spleen, pancreas, kidney, adrenal, testis did not differ from controls.

GROSS PATHOLOGY
- Gross pathology did not reveal marked differences between treated animals and their controls.

HISTOPATHOLOGY: NON-NEOPLASTIC
- Histopathology did not reveal marked differences between treated animals and their controls.
- Due to the small differences compared to controls, it is difficult to assess whether inflammatory focal cell infiltration of pancreas, interstitual cell hyperplasia in the testis and Leydig cell tumours seen in the groups after 1 year of treatment (1 or 2 animals each) as well as after cessation (1 animal each) was treatment-related. In contrast to the authors’ opinion, no clear recovery of liver and kidney lesions was observed after 16 weeks of cessation.

OTHER FINDINGS
- Systolic blood pressure, and pulse rate did not show any differences between treatment and control groups.
- At the end of the treatment period, plasma samples contained 0.18, 0.31 and 0.46 µg V/ml.
- At weeks 6 and 13 following withdrawal of V, no detectable amounts of V were found.
- Non-fasting blood glucose and fasting plasma glucose were not influenced by VOSO4 treatment, but fasting plasma insulin was reduced compared to the controls.
- VOSO4 treatment had no effect on triglycerides and cholesterol compared to the controls.
- A dose-related increase of V concentrations in various tissues was observed with a ranking bone>kidney testis>liver>plasma>pancreas>brain. After 16 weeks of cessation, small concentrations of V could be detected only in brain and kidney indicating some affinity of V to thes tissues but not in plasma and in the other organs investigated.

Effect levels

Dose descriptor:

LOAEL

Effect level:

500 mg/L drinking water

Based on:

test mat.

Sex:

male

Basis for effect level:

other: body weight

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

After cessation of VOSO4 treatment, no differences between controls and V treatment groups were observed with regards to the biological parameters apart from slightly increasing body weight gain in the treatment groups adapting to normal values of the control group.

Applicant's summary and conclusion

Conclusions:

Treatment of male rats with different dose levels of vanadyl sulfate in drinking water corresponding to 34, 54 and 90 mg/kg bw/day over 52 weeks did not indicate severe signs of systemic toxicity under the conditions of this study. Body weights were dose-dependently reduced in treatment groups compared to controls, occasionally reaching statitical significance in the low and mid dose groups and at most time points in the high dose group. Based on these effects, the lowest dose level of 34 mg/kg bw/d represents a LOAEL.