线粒体通透性转换孔在缺血预处理脑保护中的作用及机制

目的：线粒体通透性转换孔通透性改变是导致缺血再灌注损伤的原因，线粒体功能的致命性改变最终引起细胞凋亡，本研究旨在观察线粒体通透性转换孔（mitochondrial permeability transition pore,MPTP）在缺血再灌注及缺血预处理脑保护中的作用；方法：将体外培养8天的海马神经元细胞分为五组，正常对照组（A组），缺血再灌注组（B组），缺血预处理＋缺血再灌注组（C组），苍术苷＋缺血再灌注组（D组），缺血预处理＋苍术苷＋缺血再灌注组（E组）。使用流式细胞术检测各组细胞凋亡率，罗丹明123染色流式细胞术检测线粒体膜电位，Western-blot检测Bcl-2，Bax的表达。结果：与A组比较，其余四组线粒体膜电位均降低，神经元凋亡率升高（P〈0．05）；与B组比较，c组线粒体膜电位升高，神经元凋亡率升高，Bcl-2表达上调，Bax表达下调（P〈0．05）；与c组比较，E组粒体膜电位降低，神经元凋亡率升高，Bcl．2表达下调，Bax表达上调（P〈0．05）。结论：我们在细胞及分子生物学水平对MPTP及缺血预处理的研究后发现，缺血预处理能有效减轻海马神经元缺血再灌注损伤，抑制缺血再灌注后神经细胞凋亡，其机制与抑制MPTP的开放有关。

The Role and Mechanism of Mitochondrial Permeability Transition Pore in Cerebral Protection by Ischemic Preconditioning

Objective： The increased permeability of the mitochondrial permeability transition pore （MPTP） has been proved the reason of ischemia reperfusion injury. Therefore, many deadly changes of the mitochondrial functions initiate apoptosis pathway, leading cell apoptosis. The study is to explore the role of MPTP in cerebral ischemia reperfusion and ischemia preconditioning. Methods： The primary hippocampal neuron cells of newborn Wistar rats were cultured for 8 days and randomly divided into five groups： Control group （A）, ischemia reperfusion group （B）, ischemia preconditioning＋ischemia reperfusion group （C）, atractyloside＋ischemia reperfusion group （D） and hypoxic preconditioning＋atractyloside＋ischemia reperfusion group （E）. Cell apoptosis rates in each group were measured by flow cytometry; the mitochondrial membrane potential was detected by flow cytometry through Rhodamine 123 staining. Western bolt was adopted to investigate the expression of Bcl-2 and Bax. Results： The mitochondrial membrane potential reduced and the apoptosis r- ate increased significantly （P〈0.05） in the other groups, compared those with Group A; Compared to the group B, the mitochondrial membrane potential increased and the apoptosis rate decreased significantly in group C （P〈0.05）. The expression of Bcl-2 increased（P〈 0.05）, while Bax decreased （P〈0.05）. Compared to the group C, the mitochondrial membrane potential decreased and the apoptosis rate increased in the group E （P〈0.05）. The expression of Bcl-2 decreased（P〈0.05）, while Bax increased （P〈0.05）. Conclusion： We explored the mechanism of MPTP and ischemia preconditioning in isehemia reperfusion injury on the level of cellular and molecular biology. Ischemia preconditioning decreases the apoptosis induced by ischemia reperfusion injury in hippocampal neuron cells, which is related to the inhibition of the mitochondrial permeability transition pore.