依达拉奉对心肌梗死大鼠心肌细胞凋亡的抑制作用及机制研究

Inhibitory effect of edaravone on apoptosis of myocardial cells in rats with myocardial infarction and its mechanism

目的探讨依达拉奉对心肌梗死(MI)大鼠心肌细胞凋亡的抑制作用及其作用机制。方法 50只SD大鼠随机分为假手术对照组、模型对照组、依达拉奉小剂量、中剂量及大剂量组5组。除假手术对照组外,其他4组大鼠均结扎冠状动脉左前降支复制MI模型。依达拉奉小剂量、中剂量及大剂量组分别腹腔注射依达拉奉1、3和6 mg/kg,假手术对照组和模型对照组大鼠注射同体积生理盐水。各组大鼠模型复制2 h后开始给药,连续给药14 d后进行相关检测,采用高分辨小动物超声仪测定大鼠心脏结构和功能,取腹主动脉血检测血清心肌酶(cTn T、CK-MB、LDH)和抗氧化标志物(SOD、MDA、GSH-Px),采用TUNEL法测定心肌细胞凋亡指数,采用RT-PCR法检测心肌PI3K、Akt、Bcl-2及Bax mRNA表达,采用Western blotting检测心肌PI3K、Akt、p-Akt、Bcl-2及Bax蛋白的表达。结果依达拉奉呈剂量依赖性降低MI大鼠左心室舒张末期内径(LVESD)和左心室收缩末期内径(LVEDD)水平(P<0.05),升高左心室射血分数(LVEF)和左室短轴率(LVFS)水平(P<0.05);依达拉奉呈剂量依赖性降低MI大鼠血清c Tn T、CK-MB和LDH水平(P<0.05);依达拉奉呈剂量依赖性升高大鼠血清SOD和GSH-Px水平(P<0.05),降低MDA水平(P<0.05);依达拉奉剂量依赖性抑制MI大鼠心肌细胞凋亡指数(P<0.05);依达拉奉呈剂量依赖性升高MI大鼠心肌PI3K、Akt和Bcl-2 mRNA的表达(P<0.05),降低Bax mRNA的表达(P<0.05);依达拉奉呈剂量依赖性升高MI大鼠心肌PI3K、Akt、p-Akt及Bcl-2蛋白的表达(P<0.05),降低Bax蛋白的表达(P<0.05)。结论依达拉奉对MI大鼠心脏具有保护作用,可降低心肌细胞的凋亡,改善心肌抗氧化能力,并且调控PI3K/Akt信号通路。

Objective To investigate the inhibitory effect and mechanism of edaravone on apoptosis of myocardial cells in rats with myocardial infarction. Methods A total of 50 SD rats were randomly divided into sham operation control group, model control group, low dose edaravone group, medium dose edaravone group and high dose edaravone group. The left anterior descending branches of the coronary artery in rats were ligated to establish myocardial infarction models except those in sham operation group. Rats in low-dose group, medium-dose group and high-dose group were given intraperitoneal edaravone of 1 mg/kg, 3 mg/kg and 6 mg/kg respectively, and rats in sham operation group and model control group were given same volume of normal saline. All test were conducted in 2 hours after operation, and treatment duration continued for 2 weeks. Cardiac structure and function were determined by high resolution of animal ultrasonic instrument;serum myocardial enzyme markers(cTnT, CK-MB, LDH) and antioxidant markers(SOD, MDA and GSH-px) in abdominal aorta blood were determined;myocardial apoptosis indexes were evaluated by TUNEL method;the mRNA expressionof PI3 K, and Akt, the Bcl-2 and Bax in myocardium were determined by RT-PCR;the protein expressions of PI3 K, Akt, p-Akt, Bcl-2 and Bax were determined by western-blotting. Results Edaravone decreased LVESD and LVEDD in rats with myocardial infarction(P<0.05) and increased LVEF and LVFS(P<0.05) in dose-dependent manner. Edaravone decreased serum levels of cTnT, CK-MB, LDH in rats with myocardial infarction(P<0.05) in dosedependent manner. Edaravone increased serum levels of SOD and GSH-px(P<0.05) and decreased serum level of MDA(P<0.05) in a dose-dependent manner. Edaravone decreased apoptosis index of myocardial cells in rats with myocardial infarction(P<0.05) in a dose-dependent manner;Edaravone increased mRNA expression of PI3 K, Akt and Bcl-2 in rats with myocardial infarction(P<0.05) and decreased mRNA expression of Bax(P<0.05) in a dose-dependent manner. Edaravone increased protein expression of PI3 K, Akt, p-Akt and Bcl-2 in rats with myocardial infarction(P<0.05), and decreased protein expression of Bax protein(P<0.05) in a dosedependent manner. Conclusion Edaravone has a heart-protective effect in rats with myocardial infarction and can reduce apoptosis of myocardial cells, improve myocardial antioxidant capacity, and regulate the PI3 K/Akt signaling pathway.