Antioxidant therapy and streptozotocin-induced diabetes in pregnant rats

The aim of our study was to analyse the effect of chronic hyperglycaemia on lipid peroxidation and scavenging enzyme activity in pregnant animals and their offspring supplemented and not supplemented with vitamin E - a natural antioxidant. Thirty pregnant female Wistar rats were used in our experiments. Diabetes was induced on day 7 of pregnancy using a single does of streptozotocin (40 mg/kg). Diabetic animals were divided into two equal groups: vitamin E supplemented and those fed with standard diet. Our controls consisted of 15 healthy rats. On day 1 after delivery homogenates of maternal liver and uterus as well as neonatal lungs and liver were prepared. Then the following parameters were measured: malondialdehyde (MDA) concentrations in the homogenates and blood serum, glutathione (GSH) levels, the activity of CuZn superoxide dismutase (SOD) and glutathione peroxidase (GPx) (Bioxytech, France). Statistical analysis was performed using Mann-Withney U test. The neonates of diabetic rats were smaller than those from healthy rats and serum glucose concentration was markedly higher in diabetic animals, both in mothers and neonates. MDA levels increased significantly, whereas GSH content and SOD as well as GPx activities were markedly diminished in diabetic pregnant rats and their offspring in comparison with the control group. In animals supplemented with tocopherol, MDA concentrations declined significantly, GSH contents and SOD activities were markedly elevated in almost all types of tissues studied, whereas glutathione peroxidase remained suppressed. Our results suggest that diabetic pregnant rats and their neonates are exposed to oxidative stress (OS), but vitamin E supplementation could in part reduce the imbalance between uncontrolled reactive oxygen species generation and scavenging enzyme activity, and may potentially serve as a useful prophylactic factor against OS development: