酸处理对大鼠离体心脏缺血再灌注损伤的影响及PI3K/Akt信号通路在其中的作用

目的 评价酸处理对大鼠离体心脏缺血再灌注损伤的影响及磷脂酰肌醇-3激酶/蛋白质丝氨酸苏氨酸激酶(PI3K/Akt)信号通路在其中的作用.方法 清洁级SD大鼠70只,雌雄不拘,体重450-550 g,随机分为7组(n=10):缺血再灌注组(I/R组)、缺血后处理组(IPO组)、酸处理组(H+组)、缺血后处理+碱处理组(IPO+OH-组)、碱处理组(OH-组)、酸处理+渥曼青霉索组(H++wort组)和渥曼青霉素组(wort组).采用Langendorff装置行离体心脏灌注,采用全心停灌30 min、再灌注中性K-H液(pH值7.4)120 min的方法 制备大鼠离体心脏缺血再灌注模型.IPO组于再灌注即刻灌注中性K-H液15 s,停灌15 s,重复6次,行缺血后处理;H+组于再灌注即刻灌注经80%O2-20%CO2饱和的酸性K-H液(pH值6.9)3 min;IPO+OH-组于再灌注即刻灌注经100%O2饱和的碱性K-H液(pH值7.8)3min,并行缺血后处理;OH-组于再灌注即刻灌注碱性K-H液3 min;H++wort组于再灌注即刻灌注含100 nmol/L渥曼青霉素的酸性K-H液3 min;wort组于再灌注即刻灌注含100 nmol/L渥曼青霉素的中性K-H液3 min.于缺血前和再灌注30 min时记录左心室舒张末期压(LVEDP)和左心室压力最大上升和下降速率(±dp/dtmax);于再灌注30 min时测定冠状动脉流出液一氧化氮(NO)浓度;于再灌注120 min时,计算心肌梗塞区与缺血危险区的质量比,来表示心肌梗塞范围.结果 与I/R组比较,IPO组和H+组再灌注时LVEDP降低,±dp/dtmax升高,心肌梗塞范围减小,冠状动脉流出液NO浓度升高,OH-组、H++wort组心肌梗塞范围增加,wort组心肌梗塞范围增加,冠状动脉流出液NO浓度降低,IPO+OH-组LVEDP降低(P<0.05或0.01),±dp/dtmax、心肌梗塞范围和冠状动脉流出液NO浓度差异无统计学意义(P>0.05);IPO组与H+组上述指标比较差异均无统计学意义(P>0.05).结论 酸处理可减轻大鼠离体心脏缺血再灌注损伤.其机制与激活PI3K/Akt信号通路有关.

Effects of acidic reperfusion on ischemia-reperfusion injury in isolated rat teart: role of PDK/Akt signaling pathway

Objective To investigate the effects of acidic reperfusion on ischemia-reperfusion injury in isolated rat heart and the role of PI3K/Akt signaling pathway.Methods Seventy adult SD rats weishing 450-550 g were randomly divided into 7 groups(n=10 each):group Ⅰ ischemia-repedusion injury(X/R);groupⅡ ischemic post eonfioning(IPC);group Ⅲ acidic reperfusion(H+);group Ⅳ ischemie postconditioning+alkalotic nsperfusion(IPC+OH-);group Ⅴ alkalotic reperfusion(OH-);group Ⅵ acidic repeffusion+wortmannin (H+wort)and group ⅦVl wortmannin(wort).The animals were anesthetized with intraperitoneal(IP)urethane. Their chests were opened and hearts were excised and passively perfused in a Lsngendorff apparatus with KrebsHenseleit buffer(KHB)saturated with 95%O2-5%O2 at 37℃.The isolated hearts were made globally ischemic for 30 min followed by 120 rain reperfusion.Group II (IPC)WaS subjected to 6 cycles of 15 rain reperfusion and 15 min ischemia at the beginning of reperfusion. In group H+ and OH- (group Ⅲ ,Ⅴ ) the isolated hearts were perfused with KHB of pH 6.9 and 7.8 for 3 rain respectively at the beginning of reperfusion. In group IPC + OH( Ⅳ ) the isolated hearts were perfused with KHB of pH 7.8 for 3 rain followed by IPC. In group H + wort and wort ( Ⅵ,Ⅶ ) the isolated hearts were perfused with wortmannin 100 nmol/L in KHB of pH 6.9 and 7.4 for 3 min respectively at the beginning of reperfusion. LVEDP and ± dp/dtmax were measured before ischemia and at 30 min of reperfusion. Coronary effluent was collected for determination of NO concentration at 30 min of reperfusion. Lnfart size was measured at 120 rain of reperfusion. Results The LVEDP was decreased, ±dp/dt was increased, the infarct size was smaller and the NO concentration in coronary effluent was higher in group IPO and H+ compared with group I/R. Wortmannin abolished the protective effect of acidic reperfusion on isolated rat heart. Conclusion PI3K/Akt signaling pathway may be involved in the protective effects of acidic reperfusion on myocardium against ischemia-reperfusion injury.