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

Poly （ADP-ribose） polymerase contributes myocardial ischemia-reperfusion of rats by regulating Akt signaling pathway

目的探讨多二磷酸腺苷（ADP）-核糖聚合酶[poly（ADP—fibose）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（Westemblot）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-3p，GSK-3B）和叉头转录因子FOX03a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．3B和磷酸化FOX03a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-3B和磷酸化FOX03a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。

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-313 （GSK-313） and forkhead transcription factor FOXO3a were detected. Results （ 1 ） The expression of PARP were significantly upregnlated 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 〈 O. 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-313 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.