螺内酯抑制心肌细胞凋亡机制的初步研究

Mechanism of spironolactone inhibiting cardiac myocyte apoptosis

目的初步探讨螺内酯(spironolactone,SPI)抑制心肌细胞凋亡的机制以及心肌梗死后对心室重构的影响。方法 45只SD大鼠分为3组:假手术假手术组、心肌梗死(myocardial infarction,MI)组和心肌梗死后SPI干预组。测量大鼠左心室功能、观察标本病理形态改变,缺口末端标记法(TUNEL)检测细胞凋亡程度,免疫组化观察半胱氨酸蛋白酶8(caspase8)、半胱氨酸蛋白酶9(caspase9)。结果 (1)MI组心功能较假手术组明显下降,SPI干预组较MI组改善;(2)假手术组心肌结构完整,MI组心肌结构损害严重,SPI组心肌结构损害较轻;(3)与假手术组相比,MI组凋亡细胞数显著增加,差异有统计学意义(P<0.05);与MI组相比,SPI组心肌细胞凋亡数显著减少,差异有统计学意义(P<0.01);(4)与假手术组相比,MI组半胱氨酸蛋白酶8、半胱氨酸蛋白酶9表达显著增加,差异有统计学意义(P<0.01);与MI相比,SPI组半胱氨酸蛋白酶8表达无明显差异,而半胱氨酸蛋白酶9表达明显下降,差异有统计学意义(P<0.01)。结论螺内酯通过抑制细胞凋亡改善了心室重构和心力衰竭的发生发展,可能通过凋亡的内源性途径抑制了心肌细胞的凋亡。

Objectives To investigate the mechanism of spironolactone（SPI） on myocardial cell apoptosis and the influence on myocardial remodeling in rat hearts after myocardial infarction（MI）.Methods MI was achieved by permanent occlusion of the left coronary artery.Sprague-Dawley rats were divided into three groups：（1） sham group; （2） untreated MI group; （3） SPI-treated MI group.MacLab left ventricular developed pressure （LVDP）,＋dp/dtmax and-dp/dt,max were compared within the three groups.Expressions of caspase8,caspase9 in myocardium were measured by immunohistochemistry.Myocardial apoptosis was determined by TUNEL stain.Results （1） Cardiac function in MI group significantly decreased compared to that in sham group;SPI group was better than MI group.（2） Cardiomyocyte injury was more severe in MI group than in SPI group.（3）The number of apoptotic cells significantly increased in MI group （P〈0.05）,while SPI markedly inhibited myocardial cell apoptosis after MI （P〈0.01）.（4） Expressions of caspase8 and caspase9 significantly increased in MI group than in sham group （P〈0.01）.Caspase8 in SPI group showed no significant difference compared with that in MI group （P〉0.05）.Caspase9 in SPI group significantly decreased compared with that in MI group （P〈0.01）.Conclusions SPI may protect cardiomyocytes from MI and improve myocardial remodeling by inhibiting their apoptosis by intrinsic pathway.