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目的探讨ATP敏感性钾通道开放剂pinacidil对大鼠脑缺血再灌注后神经元凋亡的保护作用及信号转导机制。方法 100 只Wistar 雄性大鼠随机分为四组:A 组(假手术组)、B组 (缺血组)、C 组 (KATP开放剂处理组)及D组 (KATP开放剂和阻断剂处理组)。用线栓法制备大鼠大脑中动脉缺血(middle cerebral artery occlusion,MCAO)模型,用DNA断端末端标记法(terminal-deoxynucleotidytransferase-mediated dUTP-biotin nick end labeling,TUNEL)检测神经元凋亡,用原位杂交方法检测caspase-3、caspase-8及caspase-9 mRNA的表达。结果 (1) C组12 h、24 h、48 h、72 h 时间点的凋亡细胞数较 B、D 组显著减少(P<0.05 或 P<0.01) ;B 组和 D组之间无显著性差异(P>0.05)。(2) C 组 caspase-3 mRNA 和 caspase-8 mRNA 在各时间点及 caspase-9 mRNA 在 12 h、24 h、48 h、72h 时间点的表达显著少于B组和D组(P<0.01或P<0.05),B组和D组之间无显著性差异(P>0.05)。结论 KATP通道开放剂能显著减少大鼠脑缺血再灌注后的细胞凋亡及caspase-3、caspase-8及caspase-9 mRNA的表达。KATP通道开放剂可能通过抑制线粒体通路和死亡受体通路降低神经元凋亡,保护缺血再灌注损伤后的脑组织。
Objective To investigate the protective effect of pinacidil, an ATP-sensitive potassium channel opener, on neuronal apoptosis after cerebral ischemia-reperfusion in rats and its signal transduction mechanism. Methods 100 Wistar male rats were randomly divided into four groups: A group (sham operation group), B group (ischemia group), C group (KATP opener treatment group) and D group (KATP opener and blocker treatment group). The middle cerebral artery occlusion (MCAO) model was established by the method of thread occlusion. The apoptosis of neurons was detected by terminal deoxynucleotidy transferase-mediated dUTP-biotin nick end labeling (TUNEL) In situ hybridization was used to detect the expression of caspase-3, caspase-8 and caspase-9 mRNA. Results (1) The number of apoptotic cells in group C at 12 h, 24 h, 48 h and 72 h was significantly lower than that in groups B and D (P <0.05 or P <0.01). There was no significant difference between group B and group D Sex differences (P> 0.05). (2) The expression of caspase-3 mRNA and caspase-8 mRNA in group C at each time point and caspase-9 mRNA at 12 h, 24 h, 48 h and 72 h were significantly less than those in groups B and D (P <0.01) Or P <0.05). There was no significant difference between group B and group D (P> 0.05). Conclusions KATP channel opener can significantly reduce the apoptosis and the expression of caspase-3, caspase-8 and caspase-9 mRNA after cerebral ischemia-reperfusion in rats. KATP channel opener may reduce neuronal apoptosis by inhibiting mitochondrial pathway and death receptor pathway and protect brain tissue after ischemia-reperfusion injury.