大鼠急性心肌梗死后心脏血流动力学参数、心肌组织病理学及c-kit mRNA表达的变化

The Changes of Hemodynamic Parameters,Pathology and c-kit mRNA Expression in Myocardium after Acute Myocardial Infarction in Rats

探讨大鼠急性心肌梗死(AMI)后不同时间点心脏血流动力学参数、心肌组织病理学和c-kitmRNA表达水下的变化及三者之间的相互关系。66只成年雄性SD大鼠随机分为:正常组、假手术组和结扎组。通过结扎冠状动脉左前降支建立AMI模型。实验结束后,检测心脏血流动力学参数、心肌组织病理学变化和c-kit mRNA的表达水平。结果表明,正常组与各假手术组间血流动力学参数无明显差异(P>0.05)。与正常组相比,各结扎组的左心室收缩压(LVSP)、左心室内压力最大上升速率和最大下降速率(±dp/dtmax)均明显降低(P<0.01);左心室舒张末期压力(LVEDP)明显上升(P<0.01)。但与结扎6 h组相比,其余各结扎组的LVSP、LVEDP、±dp/dtmax均明显升高(P<0.05)。结扎区心肌组织HE染色显示,与正常组相比,6 h结扎组心肌细胞无明显形态学改变;1 d结扎组细胞核固缩或碎裂,横纹不清或消失,大量心肌发生坏死;3 d结扎组心肌细胞结构消失,坏死区形成,并可见大量炎症细胞浸润;7 d结扎组中性多核细胞浸润更加明显,弥漫整个坏死区域;14 d结扎组可见梗死区周边有肉芽组织长入,并伴大量的中性多核细胞浸润。RT-PCR显示,c-kit mRNA在正常组和假手术组心肌组织中有低水下表达,但二者无明显差异(P>0.05)。结扎各组从3 d到14 d,心肌组织中c-kit mRNA表达分别为相应假手术组的1.46倍、1.91倍、2.67倍。提示,AMI后前2周内,受损心肌组织结构和心脏功能已开始修复,而c-kit+心肌干细胞在心肌的再生修复过程中可能发挥重要作用。

This study was aimed to investigate the changes of hemodynamic parameters, pathology and c kit mRNA expression in myocardium after acute myocardial infarctionin （AMI） in rats, and to elucidate the relationship between these three kinds of changes. Sixty six adult male SD rats were randomly divided into normal group , Sham groups and ligation groups. The rat model of AMI was set up by llgating the left anterior descending artery. Hemodynamic parameters, pathological changes and c kit mRNA expression in myocardiam were examined. The results revealed that there were no statistically significant differences in hemodynamic parameters between normal group and Sham groups. Compared with the normal group , all ligation groups exhibited significantly decreased left ventricular systolic pressure （LVSP） and ＋dp/dtmax （P〈0. 01）, and increased left ventricular end diastolic pressure（LVEDP, P〈0. 01）. In the other ligation groups, compared with 6th hour group after ligation, there appeared striking increase of LVSP, LVEDP and ±dp/dtmax （P〈0.05）. HE staining in myoeardiam showed that there are necrosis and derangement at 24^th hour group after ligation ,and a great number of inflammatory cells infiltration around the infarct zone at 3^rd day group after ligation, and granulation tissue infiltrated into the infarct zone at 14^th day group after ligation. In all five time points groups after ligation, the levels of c-kit mRNA expression were 0. 99 fold, 1.06 fold, 1.46 fold, 1.91 fold and 2.67 fold, respectively, compared with Sham groups. The results suggest that cardiac stem cells in myocardium might contribute to the role of regenerating myocardium via self proliferation after acute myocardial infarction, but further investigation is still needed.