Effect of postconditioning on rat hearts suffered from long-term hypothermic preservation / 浙江大学学报·医学版

ABSTRACT

<p><b>OBJECTIVE</b>To assess the effect of postconditioning on cardiac protection of rat hearts suffered from long-term hypothermic preservation.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used. After 30 min of stabilization, the hearts were stored in 4 degrees C Celsior solution for 3 or 5 h followed by 60 min of reperfusion. Postconditioning was initiated by 3 cycles of 30 s ischemia followed by 30 s reperfusion at the beginning of subsequent persistent reperfusion. The recovery of cardiac contractile function and arrhythmia score were observed.</p><p><b>RESULTS</b>(1) Compared with control group, postconditioning increased the recovery of heart rate (HR), left ventricular systolic pressure (LVDP), maximal rise/fall rate of ventricular pressure (dP/dt(max)) and coronary flow (CF) and rate-pressure product (RPP) during reperfusion after 3 h of hypothermic preservation. However, left ventricular end-diastolic pressure (LVEDP) and the cardiac arrhythmia score during the first 10 min of reperfusion was significantly lower in 3 h postconditioning group than that in 3 h control group. (2) The rat hearts treated by postconditioning with 5-HD(100 micromol/L) abolished the amelioration of contract function induced by postconditioning. And it could also increase the cardiac arrhythmia score. (3) Compared with 5 h control group, the HR, LVDP,dP/dt(max), CF, LVEDP, RPP and the cardiac arrhythmia score were not significantly different in postconditioning treated hearts during reperfusion after 5 h of hypothermic preservation.</p><p><b>CONCLUSION</b>Postconditioning could provide the cardiac protection on 3 h hypothermic preserved rat hearts,but not on 5 h hypothermic preserved rat hearts. The cardiac protection effect might be partly associated with activation of selective mitochondrial ATP-sensitive potassium channel.</p>