Effects of diabetes on Ku70 expression and neuronal apoptosis after global cerebral ischemia/reperfusion in rats

Objective To observe the expression of Ku70 protein and neuronal apoptosis in the hippocampus of diabetic rats after global cerebral ischemia/reperfusion and explore the mechanism of diabetes in aggravating cerebral ischemia/reperfusion injury.Methods We established diabetic global cerebral ischemia/reperfusion model by induction with streptozocin(STZ) and improved Pulsinelli's four-vessel occlusion method;the model of global cerebral ischemia/reperfusion by improved Pulsinelli's four-vessel occlusion method alone served as the control.At 1,6,24 and 48 hours after ischemia,morphological changes of neurons were observed with electron microscope;the expression of Ku70 protein was measured by immunohistochemistry and Western blot;the number of apoptotic cells was counted by TUNEL method;movement and sensory functions of rats were assessed 48 hours after ischemia.Results Compared with those in the normoglycemia cerebral ischemia/reperfusion group,the number of apoptotic neurons significantly increased and the expression of Ku70 significantly decreased(P0.05) at different time points in the diabetic cerebral ischemia/reperfusion group.Meanwhile,the scores of movement and sensory functions decreased in the latter group(P0.05).Conclusion Diabetes can aggravate apoptosis of nerve cells after global cerebral ischemia/reperfusion injury,which is related to the downregulation of Ku70 expression.