Effect of nicorandil on the function of coronary artery endothelium during hypoxia reoxygenation / 中华胸心血管外科杂志

ABSTRACT

Objective To study the effect of nicorandil on the function of coronary artery endothelium during hypoxiareoxygenation.Methods Forty-five fresh porcine left anterior descending coronary artery rings in 2mm long were randomly divided into five groups.Control group ( n =9)incubation in Krebs-Henseleit (KH) at 37℃ for 90 minutes with a constant supply of oxygen ; Group A ( n =9)30-minute hypoxia ( PO2 ＜ 15 mm Hg) followed by 30 minutes reoxygenation in KH at 37℃ ; Group B ( n =9)60-minute hypoxia followed by 30 minutes reoxygenation in KH at 37 ℃ ; Group C ( n =9)60-minute hypoxia followed by 30 minutes reoxygenation in KH added nicorandil ( 0.2 μmol/L) at 37 ℃ ; Group D ( n =9 )60-minute hypoxia followed by 30 minutes reoxygenation in KH added nicorandil (0.2 μmol/L) and 5-hydroxydecanoate ( 10μmol/L) at 37 ℃.The endothelium-derived hyperpolarizing factor (EDHF) -mediated relaxation ( U46619 precontraction) induced by bradykinin in the present of indomethacin (7 μmol/L),LNNA (300 μmol/L) and oxyhemoglobin (20 μmol/L)were measured in the organ chambers.Results Compared with control group,the relaxation was significantly decreased in group A,B and D ( P ＜ 0.001 ),while there is no significant difference in group C ( P ＞ 0.05 ).Compared with group A,the relaxation was significantly reduced in group B and D (P ＜0.001 ).Conclusion Hypoxia-reoxygenation impairs EDHF mediated relaxation in coronary artery with more injury during prolonged hypoxia.This function can be restored by preconditioning with nicorandil The mechanism is mainly related to the mitochondrial ATP-sensitive K + channels.