过氧化氢预处理对抗氧化应激诱导的PC12细胞凋亡

氧化应激可明显地诱导细胞凋亡。本研究旨在探讨H2O2预处理能否对H2O2诱导的PC12细胞凋亡生产保护作用及ATP敏感性K^ （ATP-sensitive potassinm,KATP）通道在其中的作用。采用PI染色流式细胞仪（flow cytometry, FCM）检测PC12细胞凋亡。结果表明,经10μmol/L H2O2预处理90min的PC12细胞,分别在20、30、50和100μmol/L H2O2作用24h后,其细胞凋亡率明显下降,与未经H2O2的预处理的PC12细胞相比,差异极显著（P＜0.01）,表明H2O2预处理对H2O2诱导PC12细胞凋亡具有保护作用。用10μmol/L的KATP通道激动齐pinacidil(Pin)可显著减少30和50μmol/L H2O2诱导的PC12细胞凋亡,10μmol/L的KATP通道拮抗齐glybenclamide（Gly）则可显著地抑制甚至取消KATP通道激动剂Pin对H2O3诱导PC12细胞凋亡的保护作用,但并不影响H2O2预处理对H2O2诱导PC12细胞凋亡的保护作用;然而,当联合应用H2O2预处理与Pin时,对PC12细胞凋亡的保护作用显大于各自的细胞凋亡作用。提示KATP通道开放不仅对H2O2诱导PC12细胞凋亡具有保护作用,而且与H2O2预处理一起产生抗PC12细胞凋亡的协同作用。但KATP通道开放可能不参与H2O2预处理的适应性保护作用。

Hydrogen peroxide preconditioning protects PC12 cells against apoptosis induced by oxidative stress

Oxidative stress can induce significant cell death by apoptosis. We explore whether prior exposure to H2O2 (H2O2 preconditioning) protects PC12 cells against the apoptotic consequences of subsequent oxidative damages and what role the ATP-sensitive potassium (K(ATP)) channels play in the preconditioning protection. PC12 cells were preconditioned with 90 min exposure to H2O2 at 10 mumol/L, followed by 24-h recovery and subsequent exposures to different concentrations (20, 30, 50 and 100 mumol/L) of H2O2 for 24 h respectively. We used PI staining flow cytometry (FCM) to observe the apoptosis of PC12 cells. It was shown that 24-h exposures to H2O2 at 20, 30, 50 and 100 mumol/L respectively induced substantial cell apoptosis, which was greatly prevented in the preconditioning cells, indicating that H2O2 preconditioning protected PC12 cells against apoptosis induced by H2O2. Administration of pinacidil (10 mumol/L), an K(ATP) channel activator, significantly attenuated the apoptosis of PC12 cells induced by H2O2 at 30 and 50 mumol/L for 24 h respectively. Glybenclamide (10 mumol/L), a K(ATP) channel inhibitor, significantly suppressed or abolished the protective effects caused by the pinacidil but not by H2O2 preconditioning. However, when both H2O2 preconditioning and pinacidil were co-applied, their protection against the apoptosis of PC12 cells was much stronger than that of the individual one of them. These results suggest that H2O2 preconditioning protects PC12 cells against apoptosis and that the activation of K(ATP) channels is not involved in, but synergetically enhances adaptive protection of H2O2 preconditioning.