THE EFFECTS OF DESFERRIOXAMINE AND ASCORBATE ON OXIDATIVE STRESS IN THE STREPTOZOTOCIN-DIABETIC RAT

Oxidative stress and protein glycation are closely related processes t hat may contribute to the development of complications in diabetes mel litus. Treatment with antioxidants could protect against these process es at a biochemical level, and we have therefore investigated the effe cts of ascorbate and desferrioxamine treatment in the streptozotocin d iabetic rat. Diabetic animals were given ascorbate 1 g/l in drinking w ater or desferrioxamine 6 mg/kg/day by subcutaneous injection and were killed after 6 weeks. In diabetic animals, oxidative stress was incre ased as shown by increased levels of conjugated dienes (CD) in plasma and malondialdehyde (MDA) in plasma, erythrocyte membranes, and urine. In addition, there was depletion of the nutritional antioxidants asco rbate, alpha-tocopherol, and retinol. Insulin treatment returned all o f these parameters to normal. Ascorbate supplementation or desferrioxa mine treatment alone failed to reduce oxidative stress, but a combinat ion of both interventions restored MDA, CD, and antioxidant vitamins t o control values. Both ascorbate and desferrioxamine also reduced HbAl c and glycated albumin levels. Treatment with antioxidants can reduce both oxidative stress and protein glycation and may help to reduce the risk of developing diabetic complications. However, ascorbate can hav e both prooxidant and antioxidant effects in vivo, and its use in phar macological doses should be approached with caution.