促红细胞生成素对慢性心力衰竭大鼠心肌细胞的抗凋亡作用及对AKT蛋白表达的影响

摘要

目的 观察促红细胞生成素(EPO)对慢性心力衰竭(CHF)大鼠心肌细胞的抗凋亡作用及对蛋白激酶B (AKT)蛋白表达的影响.方法 30只成年雄性SD大鼠先按随机数字表法分为2组,假手术(Sham)组(n=6)和模型(Model)组(n=24);模型组采用腹主动脉缩窄术建立CHF模型,术后8周存活16只,再随机分为EPO组与对照(Control)组各8只.EPO组予以3 000 U/kg EPO腹腔注射,3次/周,连续4周;Sham组、Control组给予等量的生理盐水.分别在术后4周、8周、12周(即给药4周)行心脏彩超检查大鼠心功能.第12周末全部大鼠禁食24 h后处死,观察心肌组织细胞形态、心肌细胞凋亡及计算凋亡指数(AI);采用Western blot法检测心肌P-AKT/AKT蛋白表达情况.结果 超声心动图显示Model组4周时出现心室肥厚,8周时出现心力衰竭;EPO干预4周后较Control组左室射血分数(LVEF)明显升高(P<0.05),收缩末期室间隔厚度(IVSs)、收缩末期左心室后壁厚度(LVPWs)、舒张末期室间隔厚度(IVSd)、舒张末期左心室后壁厚度(LVPWd)明显降低(P<0.05).EPO组AI较Control组显著降低(23.87%±1.45%vs 35.58%±2.81%,P<0.01);与Sham组(0.81±0.17)比较,Control组(0.35±0.06)P-AKT/AKT OD值明显降低,EPO组(1.61±0.16)较Control组升高(P<0.01).结论 EPO可有效改善CHF大鼠的心功能,抑制心肌细胞凋亡,促进AKT的磷酸化.%Objective To investigate the effects of erythropoietin (EPO) on myocardial apoptosis and protein kinase B (AKT) expression in rats of chronic heart failure (CHF). Methods Thirty male adult SD rats were randomly divided into two groups, sham-operated (Sham) group (n=6) and model (Model) group (n=24). The abdominal aortic coarctation was used to build CHF model. Sixteen survived rats after operation were randomly divided into two groups including EPO group and con-trol (Control) group. EPO group was received 3 000 U/kg EPO intraperitoneal injection 3 times/week for 4 weeks, and Sham group and Control group were received same volume of normal saline. The echocardiography was used to evaluate cardiac function after 4 weeks, 8 weeks and 12 weeks of treatment. After 12 weeks, all rats were sacrificed after 24 h fasting. The cell morphology and myocardial apoptosis were observed, and apoptosis index (AI) was calculated. Myocardial P-AKT/AKT pro-tein expression was detected by Western blot assay. Results Echocardiography showed that ventricular hypertrophy was found in model group after four weeks, heart failure 8 weeks. Compared with Control group, left ventricular ejection fraction (LVEF) was significantly higher after EPO intervention for 4 weeks (P < 0.05), systolic interventricular septum thickness (IVSs), end-systolic left ventricular posterior wall thickness (LVPWs), diastolic interventricular septum thickness (IVSd), af-ter left ventricular end-diastolic wall thickness (LVPWd) were significantly lower (P<0.05). The value of AI was significant-ly lower in EPO group than that of Control group (23.87%±1.45%vs 35.58%±2.81%, P<0.01). The OD value of P-AKT/AKT was significantly decreased in Control group (0.35±0.06) than that of Sham group (0.81±0.17), the value was significant-ly increased in EPO group (1.61±0.16) than that of Control group (P<0.01). Conclusion EPO can improve heart function, inhibit myocardial apoptosis,and promote pro-phosphorylation of AKT in rats with chronic heart failure.