RESUMO
Objective To study the effects of ischemic postconditioning and ischemic preconditioning on cerebral ischemia-reperfusion injury following middle cerebral artery occlusion in rats.Methods A reversible focal cerebral ischemia-reperfusion injury was modeled using middle cerebral artery occlusion. Thirty male Sprague-Dawley rats were randomized into three groups (n = 10 in each group) : a cerebral ischemia-reperfusion group, an ischemic postconditioning group and an ischemic preconditioning group. The impairment of neurological function was scored and the infarct volume, the activity of superoxide dismutase and malondiadehyde (MDA) content were measured after the operation.Results In the ischemic postconditioning and preconditioning groups the neurological function was better and the infarction volume was significantly smaller compared with the model group. In the preconditioning group both infarction volume and neurological function were significantly better than in the postconditioning group. In the brain tissues of the preconditioning and postconditioning groups MDA content was lower, while the activity of superoxide dismutase was significantly higher than in the model group.Conclusions lschemic postconditioning can attenuate pathological injury induced by focal cerebral ischemia and repedusion. The neuroprotective effect induced by ischemic preconditioning is stronger than that induced by ischemic postconditioning.