Effect of vanadyl sulfate feeding on susceptibility to peroxidative change in diabetic rats

The effects of vanadyl sulfate treatment on susceptibility to oxidative stress were investigated in streptozotocin-diabetic Wistar rats. A 2 x 2 factorial design was employed, with four groups of animals: 1) untreated, non-diabetic; 2) vanadyl-treated, non-diabetic; 3) untreated, diabetic; and 4) vanadyl-treated, diabetic. Vanadyl sulfate was administered as a 1.00 to 1.25 mg/ml solution in drinking water. Cataract development was entirely suppressed in vanadyl-treated compared to untreated, diabetic rats. STZ-induction of diabetes diminished glutathione (GSH) levels in liver homogenates; whereas vanadyl treatment resulted in restored levels of this nonenzymatic antioxidant. Thiobarbituric acid reactive substances (TBARS), both basal and iron-stimulated, were significantly elevated in all vanadyl-treated animals. Vanadyl treatment lowered liver glutamine synthetase activities in diabetic rats, but not in non-diabetic animals. Thus, vanadyl treatment was antioxidant in terms of cataract formation and reduced glutathione concentration in liver homogenates, pro-oxidant by reason of iron-stimulated TBARS formation and inconclusive with respect to glutamine synthetase activity. These results highlight the importance of using multiple indicators of peroxidative change in evaluating new pro-oxidant/antioxidant treatment regimens.