磷酸肌酸对糖尿病大鼠心肌缺血再灌注时细胞凋亡的影响

目的 探讨磷酸肌酸对糖尿病大鼠心肌缺血再灌注时细胞凋亡的影响.方法 雄性SD大鼠,体重150～170 g,采用高脂饲养联合腹腔注射链脲佐菌素的方法制备糖尿病模型,造模成功的27只大鼠饲养2周后,采用随机数字表法,将其随机分为3组(n=9):假手术组(S组)、缺血再灌注组(I/R组)和磷酸肌酸组(PP组).I/R组和PP组采用结扎左冠状动脉前降支30 min再灌注2 h的方法制备心肌缺血再灌注模型,PP组于缺血前30 min腹腔注射磷酸肌酸1g/kg,I/R组给予等容量生理盐水.再灌注2 h时采集静脉血样,测定血浆肌钙蛋白T(cTnT)的浓度,然后处死大鼠,取心肌组织,采用免疫组化法测定Bcl-2、Bax和Caspase-3表达的水平,并计算Bcl-2与Bax表达的比值(Bcl-2/Bax 比),采用TUNEL染色法检测细胞凋亡情况,计算凋亡指数(AI);电镜下观察心肌细胞超微结构.结果 与S组比较,I/R组血浆cTnT浓度升高,心肌组织Bcl-2、Bax和Caspase-3表达上调,Bcl-2/Bax比降低,AI升高(P＜0.05或0.01);与I/R组比较,PP组血浆cTnT浓度降低,心肌组织Bcl-2表达上调,Bax和Caspase-3表达下调,Bcl-2/Bax比升高,AI降低(P＜0.01).PP组心肌病理学损伤程度轻于I/R组.结论 磷酸肌酸可抑制细胞凋亡,从而减轻糖尿病大鼠心肌缺血再灌注损伤,其机制与上调Bcl-2表达、下调Bax和Caspase-3的表达有关.

Abstract：

Objective To investigate the effects of phosphocreatine on apoptosis following myocardial ischemia-reperfusion (I/R) in diabetic rats. Methods Male SD rats weighing 150-170 g were used in this study.Diabetes mellitus was induced by high fat diet and intraperitoneal streptozotocin. Twenty-seven rats in which diabetes mellitus was successfully induced were randomly divided into 3 groups ( n = 9 each): sham operation group (group S);myocardial I/R group(group I/R )and phosphocreatine group (group PP). Myocardial I/R was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 2 h reperfusion in I/R and PP groups. In group PP phosphocreatine 1 g/kg was given intraperitoneally 30 min before myocardial I/R. Blood samples were collected at the end of 2 h reperfusion for determination of plasma concentration of calcium troponin T (cTnT). The animals were then sacrificed and iscbemic myocardial specimens were isolated. The expression of Bcl-2, Bax and Caspase-3 in isehemic myocarcdium was determined and Bcl-2/Bax ratio was calculated. Myocardial apoptosis was detected by TUNEL and apoptotic index was calculated. The ultrastructure of cardiomyocytes was examined with electron microscope. Results Myocardial I/R significantly increased plasma cTnT concentration and Bcl-2, Bax and Caspase-3 expression in myocardium and apoptosis index and decreased Bcl-2/Bax ratio. Phosphocreatine significantly attenuated I/R-induced above-mentioned changes and myocardial damage. Conclusion Phosphocreatine can reduce myocardial I/R injury in diabetic mellitus rats by reducing myocardial apoptosis through up-regulation of Bcl-2 expression and down-regulation of Bax and Caspase-3 expression.

Effects of phosphocreatine on apoptosis following myocardial ischemia-reperfusion in diabetic melllitus rats

Objective To investigate the effects of phosphocreatine on apoptosis following myocardial ischemia-reperfusion (I/R) in diabetic rats. Methods Male SD rats weighing 150-170 g were used in this study.Diabetes mellitus was induced by high fat diet and intraperitoneal streptozotocin. Twenty-seven rats in which diabetes mellitus was successfully induced were randomly divided into 3 groups ( n = 9 each): sham operation group (group S);myocardial I/R group(group I/R )and phosphocreatine group (group PP). Myocardial I/R was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 2 h reperfusion in I/R and PP groups. In group PP phosphocreatine 1 g/kg was given intraperitoneally 30 min before myocardial I/R. Blood samples were collected at the end of 2 h reperfusion for determination of plasma concentration of calcium troponin T (cTnT). The animals were then sacrificed and iscbemic myocardial specimens were isolated. The expression of Bcl-2, Bax and Caspase-3 in isehemic myocarcdium was determined and Bcl-2/Bax ratio was calculated. Myocardial apoptosis was detected by TUNEL and apoptotic index was calculated. The ultrastructure of cardiomyocytes was examined with electron microscope. Results Myocardial I/R significantly increased plasma cTnT concentration and Bcl-2, Bax and Caspase-3 expression in myocardium and apoptosis index and decreased Bcl-2/Bax ratio. Phosphocreatine significantly attenuated I/R-induced above-mentioned changes and myocardial damage. Conclusion Phosphocreatine can reduce myocardial I/R injury in diabetic mellitus rats by reducing myocardial apoptosis through up-regulation of Bcl-2 expression and down-regulation of Bax and Caspase-3 expression.