Effects of Exercise Pre-Conditioning on Hippocampus Expression of Bcl-2 and Bax Protein and Apoptosis Following Ischemia/Reperfusion Injury in Male Rats

Cerebral ischemia/reperfusion leads to loss of vulnerable neurons by apoptosis in specific brain regions specially in the hippocampus. There is some evidence indicating that the neuroprotective effects of physical activity on the brain. Therefore،the main purpose of this study was to investigate the effect of exercise pre-conditioning on apoptosis-related proteins expression in hippocampal CA1 neurons after induction of ischemia. 21 Male rats weighing 260-300g were randomly allocated into three groups. Sham operated group، ischemia group and exercise+ischemia group. Ischemia was induced by the occlusion of both common carotid arteries (CCA) for 20 min، The rats in exercise group were trained to run on a treadmill for 4 weeks befor induction of ischemia and in sham operated group common carotid arteries do not occluded. The expression of caspase-3، Bax and Bcl-2 proteins levels were determined by immunohistochemical staining. The number of caspase-3-positive neurons in the CA1 area were significantly increased in the ischemia group، compared with the sham-operated group. Exercise pre-conditioning significantly reduced the ischemia/reperfusion-induced caspase-3 activation، compared to the ischemia group. Moreover Bax/Bcl-2 ratio in ischemia group، significantly increased in comparision with sham-operated group. However، exercise pre-conditioning significantly attenuated the ischemia/reperfusion-induced increase in Bax/Bcl-2 ratio، as compared with the ischemia group. The results indicated that exercise pre-conditioning has a neuroprotective effects on the brain ischemia. Moreover، exercise pre-conditioning may provide a useful strategy for reducing brain complications caused by hypoxic ischemia brain injury.