RESUMO
<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>Twenty-four rats were randomly divided into 3 groups (n = 8): sham control (SC) group, ischemic/reperfusion (I/R) group and ischemic postconditioning (IPTC) group. The left ventricular peak systolic pressure and its derivate (+/- dp/dt) were calculated; The amount of myocardium collagenous were determined; The vitality of superoxide dismutase (SOD) and content of malondialdehyde (MDA) of plasma were detected; The activity of myocardium MMP-2 was measured by Western blot and RT-PCR.</p><p><b>RESULTS</b>As compared with I/R group, IPTC could lower the expression of MMP-2, ameliorate left ventricular function and increase the content of myocardium collagenous. In the meantime, the vitality of superoxide dismutase (SOD) of plasma were greatly enhanced and the content of malondialdehyde (MDA) of plasma were reduced in IFC group.</p><p><b>CONCLUSION</b>Protective effect of IPIC on myocardium may be due to reduce free radical, lower expression of MMP-2 and protect myocardial interstitium. MMPs plays an important role in the myocardial protection provided by IPTC.</p>