Abstract: Objective To explore the effects of hypoxic post-conditioning on cognitive function and the expression of silent information regulator 1 (SIRT1) in hippocampal CA1 of rats with cerebral ischemia. Methods Sixty Sprague-Dawley rats were randomly divided into sham operation group, model group and treatment group with 20 cases in each group. Each group was divided into one day, two days, three days, seven days subgroups according to the time of ischemia reperfusion. Global cerebral ischemia reperfusion was induced with modified Pulsinelli´4-vessel occlusion. The treatment group received 8% oxygen for two hours after ischemia. The cognitive function was assessed with Morris water maze test. Morphological changes of the hippocampal CA1 region were observed by HE staining. The expression of SIRT1 in the hippocampal CA1 region was detected with immunohistochemical assay and Western blotting. Results Compared with the model group, the escape latency significantly shortened (P<0.05), the number of times crossing the platform increased (P<0.05), the speed and the percentage of time spent in the platform quadrant increased (P<0.05), and the total distance decreased (P<0.05); the expression of SIRT1 in hippocampal CA1 increased (P<0.05) and the number of normal neurons increased (P<0.05) in the treatment group. Conclusion Hypoxic post-conditioning can improve the cognitive function of rats with global cerebral ischemia, which may relate with up-regulating SIRT1 in hippocampus.

Key words: cerebral ischemia, hypoxic post-conditioning, cognitive function, silent information regulator 1, rats