Abstract: Objective To explore the effect of exercise preconditioning on apoptosis and expression of P53 protein in ischemic penumbra in rats after cerebral ischemia-reperfusion. Methods Thirty- six Sprague-Dawley rats were randomly divided into sham group, model group and exercise preconditioning group, with twelve rats in each group. The middle cerebral artery occlusion (MCAO) model was established with modified Longa's method. TUNEL method was used to observe the apoptosis of neural cells in the ischemic penumbra. Western blotting was used to detect the expression of P53 protein in the ischemic penumbra. Results Twenty-four hours after cerebral ischemia-reperfusion, the number of TUNEL positive cells was more in the model group than in the sham group (P<0.01), and was less in the exercise preconditioning group than in the model group (P<0.01). The expression of P53 protein was higher in the model group than in the sham group (P<0.01), and was lower in the exercise preconditioning group than in the model group (P<0.01). Conclusion Exercise preconditioning coud down-regulate the expression of P53 protein in the ischemic penumbra, and inhibit the apoptosis of cortical cells.

Key words: cerebral ischemia-reperfusion, exercise preconditioning, apoptosis, P53, rats