中文摘要：

目的：研究西洋参茎叶总皂苷（Panax quinquefolium saponin,PQS）对大鼠急性心肌梗死（AMI）后心室重构的作用及其机制。方法：健康雄性SD大鼠90只,随机分为假手术（sham）组、AMI组、牛磺酸（300 mg.kg-1.d-1）组及PQS（50、100和200 mg.kg-1.d-1）组（n=15）。结扎大鼠左冠状动脉前降支复制AMI模型。术后第2天开始,各用药组用饮用水10 mL.kg-1.d-1溶解药物灌胃,sham组及AMI组予等量饮用水灌胃。术后4周,超声心动图检测左室结构及功能变化;TTC染色法测定心肌梗死范围;比色法测定非梗死区心肌组织羟脯氨酸含量;TUNEL法检测非梗死区心肌细胞凋亡率,Western blotting检测内质网应激分子葡萄糖调节蛋白78（GRP78）、钙网蛋白（CRT）、C/EBP同源蛋白（CHOP）及凋亡相关蛋白Bcl-2、Bax的表达。结果：与AMI组比较,PQS低、中、高剂量组左室收缩末期内径分别降低17.2%、20.3%和38.8%,左室舒张末期内径分别降低8.9%、9.0%和17.2%,左室收缩末期容积分别降低31.4%、38.5%和66.9%左室舒张末期容积分别降低18.2%、18.8%和34.2%,射血分数分别升高44.9%、60.1%和118.0%,左室短轴缩短率分别升高55.4%、71.0%和148.0%,梗死范围分别降低4.6%、39.5%和55.8%（均P〈0.05）;非梗死区心肌组织羟脯氨酸含量分别降低34.5%、35.9%和48.7%（P〈0.01）。与AMI组比较,PQS 200 mg.kg-1.d-1组心肌细胞凋亡率降低27.3%（P〈0.05）,GRP78和CRT蛋白表达分别降低79.9%和80.8%（P〈0.01）,CHOP和Bax分别降低42.5%和53.1%（P〈0.01）,Bcl-2表达升高1.1倍（P〈0.01）;上述保护作用的程度与内质网应激抑制剂牛磺酸相近（P〉0.05）。Spearman相关分析发现CHOP蛋白表达与心肌细胞凋亡率显著正相关（r=0.797,P〈0.01）。结论：PQS剂量依赖性减轻大鼠心肌梗死后心室重构,其机制与抑制CHOP介导的内质网应激凋亡通路有关。

英文摘要：

AIM ： To investigate the effect of Panax quinquefolium saponin （PQS） on ventricular remodeling after acute myocardial infarction （AMI） in rats and its mechanism. METHODS. Ninety healthy male SD rats were ran- domly divided into sham group, AMI group, taurine 300 mg · kg-1 · d-~1 group, PQS 50 mg· kg-1· d-1 group, PQS 100 mg · kg-1· d -1 group and PQS 200 mg· kg- 1 · d -1 group. AMI models were produced by ligating the left coronary arter- ies in SD rats. The rats in each treatment group were gavaged with drugs dissolved in water （ 10 mL ·kg-1 · d -1 ）, and the rats in sham group and AM! group received equal volume of water. Four weeks after MI, the left ventricle fractional short- ening, ejection fraction and structure were evaluated by echocardiography. Myocardial infarct size was measured by 2,3,5- triphenyhetrazolium chloride staining. The hydroxyproline level was measured by eolorimetric method. Apoptosis of the car- diomyocytes was detected by TUNEL. In addition, the expression of endoplasmic reticulum stress-related molecules in the noninfarcted myocardium was determined by Western blotting. RESULTS： Comoared with AMI group, the left ventricularend-systolic dimension in PQS 50 mg ·kg-1 · d-1 group, PQS 100 mg · kg-1 · d-1 group and PQS 200 mg · kg-1 · d-1 group decreased by 17. 2%, 20. 3 % and 38.8% respectively, and the left ventricular end-diastolic dimension decreased by 8.91%, 8.95% and 17.20%, respectively. The left ventricular end-systolic volume decreased by 31.4%, 38. 5% and 67. 0%, respectively, and the left ventricular end-diastolic volume decreased by 18.2%, 18. 8% and 34.2%, respective- ly. The left ventricular ejection fraction increased by 44. 9%, 60. 1% and 118.0%, respectively,and the fractional short- ening increased by 55.4%, 71.0% and 148. 0%, respectively. The infarction size decreased by 4. 6%, 39. 5% and 55.8%, respectively,and the hydroxyproline level in noninfarcted myocardium decreased by 34. 5%, 35.9% and 48.7%, respectively. Compared with AMI group,