Lipid peroxidation and scavenging enzyme activity in streptozotocin-induced diabetes

The aim of this study was to evaluate lipid peroxidation and scavenging enz yme activity in streptozotocin-induced diabetes, and then to establish whet her moderate doses of nonenzymatic antioxidant vitamin E play a role in the antioxidant defence system in diabetic pregnant rats and their offspring. The study group consisted of 30 normal female Wistar rats, which were given a single dose of streptozotocin (40 mg/kg) and were mated 7 days later. Su bsequently, the diabetic animals were divided into two matched groups: the first supplemented with vitamin E (30 mg/100 g chow), and the other fed wit h a standard diet lacking vitamin E. Controls consisted of 15 pregnant rats . On the first day after delivery, the rats were decapitated and homogenate s of maternal liver and uterus as well as neonatal lungs and liver were pre pared. Then the following parameters were measured: malondialdehyde (MDA) c oncentrations in the homogenates and blood serum, glutathione (GSH) levels, the activity of CuZn-superoxide dismutase (SOD) and glutathione peroxidase (GPx), and glycaemia. The neonates of diabetic rats were smaller than the healthy ones and serum glucose concentration was markedly higher in the dia betic animals. MDA levels were significantly increased, whereas GSH, SOD an d GPx were markedly diminished in the diabetic adult rats and their offspri ng in comparison to the control group. In the animals supplemented with a-t ocopherol, MDA concentrations were significantly lower, GSH content and SOD activities were markedly elevated most tissues studied, whereas GPx remain ed unchanged. We conclude that, by monitoring the activity of selected scav enging enzymes, information on ongoing biological oxidative stress and ther eby on the fetus/neonate status may be obtained. Our results suggest that d iabetic pregnant rats and their neonates are exposed to an increased oxidat ive stress and that vitamin E supplementation may reduce its detrimental ef fects.