Neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress in rats with streptozotocin-induced type 1 diabetes

In this study, we investigated the effects of streptozotocin-induced type 1 diabetes on antioxidant-like protein-1 immunoreactivity, protein carbonyl levels, and malondialdehyde formation, a marker for lipid peroxidation, in the hippocampus. For this study, streptozotocin (75 mg/kg) was intraperitoneally injected into adult rats to induce type 1 diabetes. The three experimental parameters were determined at 2, 3, 4 weeks after streptozotocin treatment. Fasting blood glucose levels significantly increased by 20.7–21.9 mM after streptozotocin treatment. The number of antioxidant-like protein-1 immunoreactive neurons significantly decreased in the hippocampal CA1 region, but not the dentate gyrus, 3 weeks after streptozotocin treatment compared to the control group. Malondialdehyde and protein carbonyl levels, which are modified by oxidative stress, significantly increased with a peak at 3 weeks after malondialdehyde treatment, and then decreased 4 weeks after malondialdehyde treatment. These results suggest that neurons in the hippocampal CA1 region, but not the dentate gyrus, are susceptible to oxidative stress 3 weeks after malondialdehyde treatment.