在大鼠心肌缺血再灌注中多二磷酸腺苷-核糖聚合酶通过调节Akt信号通路造成心肌损伤

摘要

Objective To investigate the effect of poly (ADP-ribose) polymerase(PARP) in heart ischemia and reperfusion (I/R) injury in rat and on Akt mediated signaling pathway.Method Rats were divided into sham,I/R,I/R + 3,4-dihydro-5-[4-(1-piperidinyl) butoxy]-1 (2H)-isoquinolinone (DPQ,10 mg/kg,i.p.),an inhibitor of PARP,I/R + DPQ + Akt inhibitor LY294002,10 mg/kg (n =12 each).Cardiac function,apoptosis of the cardiomyocytes were measured,myocardial expression of PARP,Akt,glycogen synthase kinase-3β (GSK-3β) and forkhead transcription factor FOXO3a were detected.Results (1) The expression of PARP were significantly upregulated in I/R group compared to sham group which was significantly attenuated in I/R + DPQ group(P ＜ 0.05 vs.I/R group).(2)PARP inhibition significantly reduced cardiomyocyte apoptosis from (34.0 ± 6.2) ％ to (23.0 ± 3.8) ％ (P ＜0.05).The LVDP,+ dp/dt and-dp/dt were significantly higher in I/R + DPQ group compared to I/R group (all P ＜ 0.05).(3) The expression of Akt,GSK-3β and FOXO3a were significantly upregulated in I/R + DPQ group compared to I/R group(P ＜0.05) which were significantly attenuated in I/R + DPQ + LY294002 group compared to I/R + DPQ group(all P ＜ 0.05).Conclusion PARP activation contributes to myocardial I/R injury in rats by modulating Akt mediated signaling pathway.%目的 探讨多二磷酸腺苷(ADP)-核糖聚合酶[poly (ADP-ribose) polymerase,PARP]在大鼠心肌缺血/再灌注(ischemia reperfusion,I/R)损伤中的作用及其对蛋白激酶B(PKB或Akt)信号通路的调节.方法 将48只雌性Wistar大鼠随机分为对照组(开胸,不结扎冠状动脉,亦不给予药物)、I/R组(建立I/R损伤模型,不给予药物)、I/R+ DPQ组(建立I/R损伤模型,并给予PARP的抑制剂DPQ)和I/R+DPQ+LY294002组(建立I/R损伤模型,并给予DPQ和Akt的抑制剂LY294002).末端脱氧核苷酸转移酶介导的dUTP缺口标记技术(TUNEL)检测各组大鼠心功能和心肌细胞凋亡的情况.蛋白质免疫印迹法(Western blot)检测各组大鼠心肌中PARP、Akt及其下游分子糖原合成酶激酶(glycogen synthase kinase-3β,GSK-3β)和叉头转录因子FOXO3a的表达水平.结果 (1)I/R组大鼠心肌组织中PARP表达高于对照组(P＜0.05),I/R+ DPQ组则低于I/R组(P＜0.05).(2) I/R+ DPQ组大鼠心肌细胞凋亡率为(23.0±3.8)％低于I/R组的(34.0±6.2)％,P＜0.05.I/R+ DPQ组大鼠左心室内压(LVDP)、室内压最大上升速率(+dp/dt)和室内压最大下降速率(-dp/dt)均较I/R组高(P均＜0.05).(3)I/R+ DPQ组大鼠心肌组织中磷酸化Akt、磷酸化GSK-3β和磷酸化FOXO3a的表达较I/R组高(P均＜0.05).I/R+ DPQ+ LY294002组大鼠心肌组织中磷酸化Akt、磷酸化GSK-3β和磷酸化FOXO3a的表达则较I/R+ DPQ组少(P均＜0.05).结论 大鼠心肌I/R时PARP的表达明显增加,并通过调节Akt介导的细胞信号通路导致心肌损伤.