Role of mitochondrial K_(ATP) channels in cardioprotection of hyperpolarized cardioplegia / 中国病理生理杂志

ABSTRACT

AIM: To study the protective effect of hyperpolarized cardioplegic arrest on reperfused rat heart performance and to investigate the role of mitochondrial ATP-sensitive K+ channels(mitoKATP) opening in the protection of hyperpolarized cardioplegia against ischemia/reperfusion damage.METHODS: Forty Sprague-Dawley rats were randomized into five groups(n=8 in each group) control group(Con);depolarized arrest group(D);hyperpolarized arrest group(H);depolarized cardioplegia with 5-hydroxydecanoate(5-HD) group(5HD+D);hyperpolarized cardioplegia with 5-HD group(5HD+H).The rat hearts were quickly removed to Langendorff apparatus.The heart perfusion was performed for 20 min with 37 ℃ Krebs-Henseleit buffer balanced with gas mixture(O2∶CO2=95%∶5%) at 5.8 kPa perfusion pressure,then cardial arrest was induced by different cardioplegic solution.Hearts were subjected to ischemia at 37 ℃ for 40 min followed by 30 min reperfusion.(1) The hemodynamics was detected at recovery after 30 min reperfusion.(2) Before ischemia and at the end-reperfusion,tissue was harvested for mitochondrial isolation and ultrastructure was observed by transmission electron microscopy(TEM).(3) Production of reactive oxygen species(ROS) was also determined at different time points.RESULTS:(1) Compared with end-equilibration,30 min reperfusion caused significant differences in left ventricular developed pressure(LADP),left ventricular end-diastolic pressure(LVEDP),double product(DP),heart rate (HR),coronary flow(CF)(P