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.%目的：观察低氧后处理对全脑缺血大鼠认知功能及海马CA1区沉默信息调节因子1(SIRT1)表达的影响。方法成年健康Sprague-Dawley大鼠60只，随机分为假手术组、模型组和低氧后处理组，每组20只。各组根据缺血再灌注的时间分为1 d、2 d、3 d、7 d四个亚组，每个亚组5只。采用改良Pulsinelli四血管闭塞法制备全缺血再灌注大鼠模型，低氧后处理组在缺血后给予8%低氧2 h处理。Morris水迷宫实验检测大鼠认知功能，光镜下观察海马CA1区神经细胞形态变化及存活神经细胞数量，免疫组织化学法、Western blotting检测海马区SIRT1表达。结果与模型组相比，低氧后处理组逃避潜伏期缩短(P<0.05)，穿越平台次数增加(P<0.05)，探索速度、平台象限路程百分比增加(P<0.05)，探索路程缩短(P<0.05)；海马区神经细胞损伤较轻，存活神经元细胞增加(P<0.05)；相应各时间点SIRT1表达升高(P<0.05)。结论低氧后处理能够改善全脑脑缺血大鼠的认知功能，其机制与低氧后处理提高海马组织中SIRT1蛋白表达水平有关。
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