缬沙坦对大鼠心肌缺血再灌注后无复流的影响

Effects of Valsartan on No-Reflow after Myocardial Ischemia Reperfusion in Rats

目的观察缬沙坦后处理对大鼠心肌缺血再灌注损伤后无复流的影响,并探讨其信号转导的可能机制。方法 56只雄性SD大鼠按随机数字表法分为4组:对照组(n=8),缺血再灌注(ischemia reperfusion,I/R)组(n=16),缬沙坦组(n=16,缬沙坦10mg·kg-1),缬沙坦+LY294002组(n=16,缬沙坦10mg·kg-1、LY2940020.3mg·kg-1)。大鼠适应性喂养1周后,结扎冠状动脉左前降支(LAD)60min再灌注120min,制作大鼠心肌缺血再灌注无复流模型。缬沙坦于再灌注前15min经尾静脉注射,LY294002于再灌注前5min经尾静脉注射。再灌注结束后,采用硫磺素S、伊文思蓝活体染色,观察大鼠心肌无复流范围及缺血面积;氯化三苯基四氮唑(TTC)染色评估大鼠心肌梗死面积;测血清肌酸激酶同工酶(creatine kinase isoenzyme,CK-MB);免疫印迹法(western blot)测定缺血心肌蛋白激酶B(protein kinase B,Akt)、磷酸化蛋白激酶B(phosphorylated akt,p-Akt)、内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)和磷酸化内皮型一氧化氮合酶(phosphorylated eNOS,p-eNOS)的蛋白表达。结果与I/R组相比,缬沙坦组的无复流面积减少[(31.26±2.83)%比(21.60±3.29)%,P<0.01],梗死面积减少[(40.16±4.19)%比(27.93±4.57)%,P<0.01],Akt、eNOS的磷酸化程度增高(P<0.01);缬沙坦联合应用LY294002后,该组与缬沙坦组相比,其无复流面积及梗死面积均有增加(P<0.01)。结论缬沙坦可以明显减少大鼠心肌缺血再灌注后无复流面积和梗死面积,其作用机制可能与磷脂酰肌醇3-激酶(phosphatidylinosi-tol 3-kinase,PI3K)/Akt/eNOS信号转导途径的激活有关。

Objective To evaluate the effects of valsartan on myocardial no-reflow after ische- mia-reperfusion in rats,and to investigate the signal transduction mechanism. Methods Fifty-six male SD rats were randomly assigned to four groups：control group （n=8）,ischemia and reperfu- sion group （n=16）,valsartan group（10 mg · kg^-1,n=16）,and valsartan＋LY294002 group（val- sartan 10 mg · kg^-1,LY294002 0.3 mg · kg^-1,n=16）.After acclimatization for 1 week,the left anterior descending coronary artery was occluded for 60 minutes and reperfused for 120 minutes to establish myocardial ischemia-reperfusion no-reflow model. Valsartan （10 mg -·kg^-1 ） and LY294002（0.3 mg · kg^-1） were administered via tail vein 15 and 5 minutes before reperfusion, respectively. After reperfusion,myocardial no-reflow zone and ischemic area were observed using Thioflavin S and Evans blue staining and myocardial infarct size was measured using triphenyhet-razolium chloride （TTC） staining. The levels of serum creatine kinase isoenzyme （CK-MB） were detected after treatment. The expression of Akt, p-Akt, p-eNOS and eNOS was determined by western blotting. Results Compared with ischemia and reperfusion group,valsartan increased the expression of p-Akt and p-eNOS （P 〈 0. 01）, reduced no-reflow area F（31. 26 士 2. 83）% vs （21.60士3.29）%,P%0.01],and decreased infarct sizeP（40.16士4.19）% vs （27.93士4.57）%, P〈0.01]. However,these effects were reversed by LY294002（P〈0.01）. Conclusion Vatsartan can reduce myocardial no-reflow area and infarct size after ischemia-reperfusion via PI3K-Akt- eNOS signal transduction pathway.