| Objective To study the protective effect of Oxymatrine preconditioning against myocardial ischemia-reperfusion(I/R) injury and the protective mecha-nism.Methods Sixty male SD rats weighing 280-300 g were randomly divide d into 5 equal groups, namely the I/R group( group IR), Oxymatrine preco nditioning group(group OMT), Oxymatrine preconditioning + chelerythrine g roup(group OC), chelerythrine preconditioning group(group CHE), and isch emia precondition group(group IP). Myocardial I/R model was established b y ligation of the left anterior descending coronary artery for 30 minutes, fol lowed by reperfusion for120 minutes. Ischemia precondition model was estab lished by ligation of the former artery for 5 minutes followed by reperfusio n for 5minutes, repeat three cycles. Electrocardiogram, heart rate and mean arterial pressure(MAP) were continuously monitored during I/R. At the end of reperfusion, blood samples were obtained to determine plasma activation of CK-MB and LDH. and the myocardial tissues were obtained to detect the SOD and MDA. After reperfusion, HE staining to observe the pathological changes of myocardial tissues.AI of myocardium was determined by TUNEL.Using the Pep Tag® Assay for Non-Radioactive Detection of Protein Kinase C or c AMP-Dependent Protein Kinase system to detect the activity of PKC;Western blotting were performed to assess the expression of PKC epsilon a nd the subunits of ATP-sensitive potassium channel. Using SPSS20.0 statistical analysis software package to analysis the results, groups were compared using One-way ANOVA analysis, P <0. 05 was the statistically different b oundaries.Results After reperfusion, Oxymatrine preconditioning significantly lowe red the levels of CK-MB(P<0.05),LDH(P<0.05), MDA(P<0.05),AI(P<0.05) and raised the levels of SOD(P<0.05) compared with those in the I/R g roup. The Oxymatrine preconditioning group also showed lower levels of C K-MB and LDH than the ischemia precondition group(P<0.05). The levels of SOD, MDA and AI indicated no significant differences between Oxymatri ne preconditioning groups and ischemia precondition group. The activity of PKC and the expression of PKC epsilon are increased, Kir6.1 and SUR1 le vels are also increased.Kir 6.2 showsa lower level,SUR2 A and SUR2 B sho w no significant difference in expression levels compared to the IR group.Conclusion: Oxymatrine preconditioning protects myocardium on Myocar dial Ischemia-reperfusion Injury, which may be related to the endogenous pr otective mechanism, OMT regulates the activity of PKC and increases the e xpression of PKC epsilon,also regulates the subunits of ATP-sensitive potass ium channel, including increase of SOD levels and the reduction of cell apo ptosis. |
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