ATP敏感性钾通道开放剂对大鼠脑缺血再灌注后caspase-12 mRNA及蛋白表达的影响

目的 观察ATP敏感性钾通道(KATP)开放剂对大鼠脑缺血再灌注后caspase-12mRNA和蛋白表达的影响,探讨内质网信号通路是否参与了KATP开放剂对脑缺血后神经元凋亡的抑制机制.方法 200只Wistar雄性大鼠随机分为假手术组,缺血再灌注组,开放剂组及阻断剂组.应用线栓法制备大鼠大脑中动脉缺血再灌注模型,分别应用免疫组化染色、RT-PCR技术检测脑缺血再灌注后各组caspase-12蛋白及mRNA的表达.结果 在缺血再灌注组,开放剂组及阻断剂组,随着缺血再灌注时间的延长,caspase-12mRNA及蛋白的表达逐渐增高,在缺血再灌注后24 h达高峰.开放剂组caspase-12 mRNA及蛋白表达在各时间点均显著少于缺血再灌注组及阻断剂组(P＜0.05或P＜0.01).阻断剂组各时间点与缺血再灌注组相比均无显著性差异(P＞0.05).结论 KATP开放剂可能通过抑制内质网信号通路,减少神经元凋亡,降低脑缺血再灌注损伤.

Effects of ATP sensitive potassium channel opener on the mRNA and protein expressions of caspase-12 after cerebral ischemia-reperfusion in rats

Objective To investigate effects of K(ATP) opener on the expressions of caspase-12 mRNA and protein, and to explore the role of endoplasmic reticulum (ER) stress pathway in the mechanism of K(ATP) opener protecting against neuronal apoptosis after cerebral ischemia-reperfusion. Methods Two hundred rats were randomly divided into four groups: sham operation group, ischemia-reperfusion group, K(ATP) opener group, and K(ATP) blocker group. The middle cerebral artery occlusion (MCAO) model was established by intraluminal suture occlusion method; neuronal apoptosis was detected by TUNEL staining. The mRNA and protein expressions of caspase-12 were detected by semi-quantitative RT-PCR and immunohistochemical staining, respectively. Results In ischemia-reperfusion group, K(ATP) opener group and K(ATP) blocker group, the number of apoptotic cells and the mRNA and protein expressions of caspase-12 gradually increased following cerebral reperfusion, and reached the peak at 24 h. In K(ATP) opener group, The number of apoptotic cells was significantly less than that in ischemia-reperfusion group and K(ATP) blocker group at 12 h, 24 h, 48 h and 72 h (P< 0.05 or P< 0.01); while the mRNA and protein levels of caspase-12 were significantly less than those in ischemia-reperfusion group and K(ATP) blocker group at all times (P< 0.05 or P< 0.01). There were no differences between the ischemia-reperfusion group and K(ATP) blocker group at each time (P> 0.05). Conclusion K(ATP) opener may protect neurons from apoptosis following the cerebral ischemia-reperfusion by inhibiting ER stress pathway.