The Research Of The Myocardial Apoptosis Influenced By Global Heart Ischemic Preconditioning And Relation Of The Mito-K_ATP Channels

Objective To elucidate the role of the mito-K_ATP channels in the regulation of myocardial apoptosis by using opener and inhibitor of the mito-K_ATP channels in global heart ischemic preconditioning (IPC). Methods Twenty goats were randomized into four groups: ischemia/reperfusion group (IR group, n=5), IPC group (n=5) ,DEP group (n=5) and 5-HD+IPC group(n=5), Goat hearts were subjected to 60 minutes of ischemia, followed by 90 minutes of reperfusion(RP). In IPC group, 3 cycles of IPC (5 min of aortic cross-clamping (ACC) and 5 min of aortic unclamping) were applied before 60 min ACC. Using opener of the mito-K_ATP channels before IR and using inhibitor before IPC in following groups. Cardiac myocyte apoptosis ratio was determined by TUNEL and flow cytometry with Annexin-V and propidinm iodiode (PI) staining respectively.Atomic absorption spectrometry (AAS) determine Ca2+content, protein kinaseC (PKC) activities were assessed by biochemical assay. Results IPC can significantly inhibit cardiac myocyte apoptosis, which is helpful for the recovery of cardiac performance after ischemia/reperfusion(I/R), opener of the mito-K_ATP channels may simulate IPC effect, while inhibitor can hold back this effiect. Conclusions IPC has a beneficial effect on recovery of cardiac performance by inhibiting cardiac myocyte apoptosis in goat heart after I/R with CPB. mito-K_ATP channels seems to play an important role in regulating the process.