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Objective To study the effect of Perfadex and Wisconsin Unviersity solution on the function of pulmonary artery endothelium.Methods Small lobe pulmonary arteries were dissected from nine porcine lungs.The artery from each lung was cut into six rings in 2mm.Two of them were randomly incubated in Krebs,Perfadex or Wisconsin Unviersity solution (UW solution) at 4℃ for 4 hours.Endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation (percentage of-7.5 logM U46619 precontraction) induced by bradykinin or calcium ionophone A23187 in the present of indomethacin,L-NNA and oxyhemoglobin were measured at 37 ℃ in the organ chambers.Results Vasoconstriction induced by U46619 is no significant difference among three groups (P＞ 0.05).Compared with Krebs group,the relaxation induced by bradykinin or A23187 was significantly decreased in Perfadex group (P＜0.01),while there is no significant difference in UW group (P＞0.05).Conclusion Endothelium-derived hyperpolarizing factor (EDHF) plays an important role in endothelium-mediated relaxation of porcine pulmonary artery.EDHF-mediated relaxation is impaired when the lung preserved with Wisconsin Unviersity solution,wheras its function is not affected by Perfadex solution.
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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.
RÉSUMÉ
ObjectiveTo study the impact of type 2 diabetes mellitus on endothelium of great saphenous vein in patients with coronary heart disease.MethodsPatients undergoing coronary artery bypass grafting were selected, 20 with type 2 diabetes mellitus (experimental group) and another 20 patients without (control group).The rings of great saphenous vein in I cm length were taken from those patients and then divided into 3 segments.The structure of endothelium was evaluated by the microscope and the changes of venous tone were measured in organ chamber at 37C with a constant supply of oxygen.Venous vasoconstriction was induced by phenylephrine (10-5 mol/L) and vasodilatation induced by nitroglycerin or acetylcholine (10-9 ～ 10-5 mol/L).ResultsMore damages of ultrastructure of the endothelium of saphenous vein were found in experimental group than in control group.There were no significant differences regarding the venous tone between the two groups (P ＞0.05) when vasoconstriction induced by phenylephrine and vasodilatation by nitroglycerin.However, the vasodilatation induced by acetylcholine was significantly decreased in experimental group than in control group (P ＜ 0.05).Conclusion Type 2 diabetes mellitus can aggravate the damage of endothelium of saphenous vein in patients with coronary artery disease.