[The effect of vitamin E on antioxidant tissue activity in pregnant rats with streptozocin-induced diabetes].

UNLABELLED

The aim of our study was to establish if moderate doses of nonenzymatic antioxidant, vitamin E, could play a role in the antioxidant defence system in pregnant diabetic rats and their offspring. Two models of experimental diabetes were used: the 1st group consisted of 30 female Wistar rats which were given a single dose of streptozotocin (40 mg/kg) and were mated 7 days later, whereas in the 2nd group diabetes was induced on the 7th day of pregnancy (using the same dose of streptozotocin). In each part of the experiment diabetic animals were divided into two equal groups: vitamin E supplemented and fed with standard diet only. Our controls consisted of 20 normal rats. On the 1 day after delivery rats were decapitated and 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 (colorimetric assay), glutathione (GSH) levels (colorimetric test), the activity of CuZn superoxide dismutase (SOD) (spectrophotometric method) and glutathione peroxidase (GPx) (immunoenzyme technique). Statistical analysis was performed using Mann-Whitney U test. The neonates of diabetic rats were smaller than healthy ones and serum glucose concentration was markedly higher in diabetic animals, especially in model I. 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 content and SOD activities were markedly elevated in almost all types of tissues studied, whereas glutathione peroxidase remained suppressed.

CONCLUSIONS

By monitoring the activity of chosen scavenging enzymes in homogenates and body fluids we can accumulate information on ongoing biological oxidative stress. Our results suggest that diabetic pregnant rats and their neonates are exposed to an increased oxidative stress, but vitamin E supplementation could at least in part reduce its detrimental effects.