缺血后处理对缺血／再灌注大鼠心肌基质金属蛋白酶-2表达的影响

Effect of ischemic postconditioning on the expression of myocardium matris metalloproteinase-2 induced by ischemia/reperfusion in rats

目的:探讨缺血后处理对缺血/再灌注大鼠心肌基质金属蛋白酶-2(MMP-2)表达的影响及其与心肌间质和心功能变化的关系。方法:24只SD大鼠随机分为3组(n=8):假手术组(SC组)、缺血/再灌注组(I/R组)和缺血后处理组(IPTC组)。记录各组左室血流动力学变化,观察心肌胶原含量,测定血浆中丙二醛(MDA)和超氧化物歧化酶(SOD)浓度改变。以Western blot测定MMP-2蛋白的活性,以RT-PCR法测定MMP-2 mRNA表达的变化。结果:IPTC组心肌MMP-2蛋白活性及MMP-2 mRNA表达明显降低,而心肌胶原含量、左室舒缩功能明显高于I/R组。同时,血浆SOD活力增强而MDA含量降低。结论:IPTC对I/R心肌的保护作用之一可能是通过减少自由基产生,抑制MMP-2的活性和表达,减轻了心肌间质的损伤而实现的。

Objective： To investigate the effect of ischemic postconditioning on the expression of rat myocardium matris metalloproteinase- 2（MMP-2）induced by ischemia/reperfusion（I/R） and relationship between its expression and interstitium and the effect on left ventricular function. Methods： Twenty-four rats were randomly divided into 3 groups（ n = 8） ： sham control（SC ） group, ischemic/repeffusion （ I/R ） group and ischemic postconditioning（IPIE） group. The left ventricular peak systolic pressure and its derivate（ _＋ dp/dt ） were calculated;The amotmt of myocardium collagenous were determined; The vitality of superoxide dismutase （SOD） and content of malondialdehyde （MDA） of plasma were detected; ＇Fne activity of myecardium MMP-2 was measured by Western blot and RT-PCR. Results： As compared with I/R group, lfrlE could lower the expression of MMP-2, ameliorate left ventricular function and increase the content of myocardium collagenous. In the mean- time, the vitality of superoxide dismutase （SOD） of plasma were greatly enhanced and the content of malondialdehyde （MDA） of plasma were reduced in IPYC group. Conclusion： Protective effect of IIqE on myocardium may be due to reduce free radical, lower expression of MMP-2 and protect myocardial interstitium. MMPs olavs an imoortant role in the myocardial protection orovided bv IPFC.