Abstract: Objective To investigate the changes of time process of SOD2 and free radicals in neurodegeneration induced by cerebral ischemia-reperfusion(I/R). Methods Cerebral I/R model was established through drawing out and reperfusing 40% of the whole blood volume in combination with clamping the carotid arteries for 20 min. Histological observation was performed to evaluate the neural damage; learning and memory ability was detected by Morris water maze; SOD2 activity and malonaldehyde(MDA) were determined by spectrophotometer; and expression of SOD2 was detected by western blot. Results Compared with sham group, the learning and memory ability of I/R group was significantly decreased, the hippocampal MDA level of I/R group was clearly increased in a time-dependent manner (P<0.05). SOD2 activity (14.69+2.49 U/mg.pro, 14.15+2.41 U/mg.pro, 15.07+2.67 U/mg.pro, 15.55+2.64 U/mg.pro）and protein expression (9.20+1.23, 5.40+1.03, 4.90+0.92, 5.60+0.59) of 5th d, 15th d, 30th d, and 60th d I/R group were lower than sham group (P<0.05). Histological test indicated there existed the loss and karyopyknosis of neurons in hippocampi of I/R group. Conclusion I/R-induced neurodegeneration may be related to the steady decreases of SOD2 expression and activity and increase of oxidative stress.

Key words: Ischemia-reperfusion, Neurodegeneration, Superoxide dismutase-2, Free radical