Hyperglycemia decreases preoxiredoxin-2 expression in a middle cerebral artery occlusion model.

Diabetes is a major risk factor for stroke and is also associated with worsened outcomes following a stroke. Peroxiredoxin-2 exerts potent neuroprotective effects against oxidative stress. In the present study, we identified altered peroxiredoxin-2 expression in an ischemic stroke model under hyperglycemic conditions. Adult male rats were administrated streptozotocin (40 mg/kg) via intraperitoneal injection to induce diabetes. Middle cerebral artery occlusion (MCAO) was induced surgically 4 weeks after streptozotocin treatment and cerebral cortex tissues were isolated 24 hours after MCAO. Peroxiredoxin-2 expression was evaluated in the cerebral cortex of MCAO-operated animals using a proteomics approach, and was found to be decreased. In addition, the reduction in peroxiredoxin-2 levels was more severe in cerebral ischemia with diabetes compared to animals without diabetes. Reverse-transcriptase PCR and Western blot analyses confirmed the significantly reduced peroxiredoxin-2 expression in MCAO-operated animals under hyperglycemic conditions. It is an accepted fact that peroxiredoxin-2 has antioxidative activity against ischemic injury. Thus, the findings of this study suggest that a more severe reduction in peroxiredoxin-2 under hyperglycemic conditions leads to worsened brain damage during cerebral ischemia with diabetes.