脂联素对大鼠缺血/再灌注心肌细胞凋亡及相关蛋白表达的影响

目的观察脂联素(adiponectin,APN)对大鼠缺血/再灌注(ischemia/reperfusion,I/R)诱导的心肌细胞凋亡与凋亡相关蛋白Bcl-2、Bax、Caspase-3表达的影响。方法将48只大鼠随机分成假手术组(sham group)、I/R组(I/R group)、脂联素预处理组(APN+I/R group),每组16只。结扎左冠状动脉前降支,建立大鼠心肌I/R模型。各组随机选取8只,采用Evans blue-TTC双染法测定心肌梗死面积;另外8只对心功能指标进行监测,实验结束后,采用透射电镜观察心肌组织损伤;原位末端标记(TUNEL)法观察心肌细胞凋亡情况;Western blot法测定心肌Bcl-2、Bax、Caspase-3蛋白的表达。结果脂联素明显减小I/R所致的大鼠心肌梗死面积(P<0.05),改善心脏血流动力学(P<0.05),减轻透射电镜下心肌细胞形态、细胞膜、细胞核、线粒体等结构改变,减少细胞凋亡,增加Bcl-2表达(P<0.05),降低Bax与Caspase-3蛋白表达(P<0.05)。结论脂联素对I/R损伤的保护作用与抑制心肌细胞凋亡,从而减少心肌细胞损失、减轻心脏功能障碍有关,其抗凋亡作用机制可能与上调Bcl-2表达,下调Bax及Caspase-3表达有关。

Effects of adiponectin on the cardiomyocyte apoptosis in rats induced by ischemia and reperfusion and the expression of the related protein

Aim To study the effect of adiponectin(APN) on cardiomyocyte apoptosis and the expression of Bcl-2,Bax,Caspase-3 in rats with ischemia/reperfusion(I/R).Methods The I/R injury model was established by occluding the left anterior descending branch of coronary artery for 30 min and removing the ligation later to reperfusion for 3 hours.Forty-eight rats were divided into 3 groups randomly: sham group,I/R group and APN+I/R group.The infarct size was determined by using Evens blue and TTC double dye staining in 8 rats in each group.Others were monitored hemodynamics,then the ultrastructural change of myocardial tissue was observed by transmission electron microscope;cardiomyocyte apoptosis was marked by TUNEL;Bcl-2,Bax,Caspase-3 protein expression were tested by Western blot.Results APN pretreatment could decrease infarct size and ameliorate hemodynamics of I/R.APN also could inhibit cardiomyocyte apoptosis,increase the Bcl-2 protein expression(P<0.05) and reduce the Bax and Caspase-3 protein expression(P<0.05) in rats with myocardial ischemia/reperfusion.Conclusion The preexposure to APN provides protective effect on I/R injury,which is likely associated with the inhibition of cardiomyocyte apoptosis by up-regulating Bcl-2 protein expression and down-regulating Bax,Caspase-3 protein expression.