吡那地尔预处理对不同温度高钾停跳离体兔心的保护作用

Myocardial protective effect of pinacidil pretreatment on isolated rabbit heart arrest induced with high potassium crystalloid cardioplegia at different temperatures

目的:观察ATP敏感性钾通道开放剂(KCOs)吡那地尔(Pinacidil)药物预处理对不同温度高K+停跳液灌注离体兔心肌的保护效果. 方法:离体兔心24颗以Langendorff模型灌注10 min,随机分成3组:对照组(C组):低温高K+停跳;WP组和CP组为预处理组(停跳前以Pinacidil 10 μmol/L灌注15 min):分别为常温及低温高K+停跳. 全心缺血45 min, C组及CP组心脏停跳期间的温度为26～28℃,WP组为36～38℃. 三组恢复37℃ K-H灌注20 min. 分别测定心脏停、复跳时间,心率、心律、左心室内压(LVP)及收缩力、心肌腺苷酸及脂质过氧化物丙二醛(MDA)含量,检查心肌光镜结构. 结果:三组心脏停跳时间无明显差异,预处理组复跳迅速,两组间无显著差异,C组复跳缓慢,与预处理组比较差异有显著性(P<0.05);再灌注后CP组较WP及C组心肌收缩力与LVP恢复较快(P<0.05),而WP组LVP又比C组恢复好(P<0.05). 预处理组心肌组织腺苷酸,总腺苷酸(TAN)、细胞能荷(EC)显著高于C组(P<0.01),CP组又明显高于WP组(P<0.01或P<0.05),预处理组的心肌结构也明显好于C组,CP组又好于WP组. 三组MDA含量无显著差异. 结论:Pinacidil预处理能显著增强离体兔心肌缺血/再灌注的保护效果,对低温停跳心脏的保护效果更佳.

AIM： TO evaluate the myocardial protective effect of pinacidU pretreatment on isolated rabbit hearts arrested with high potassium crystalloid cardioplegic solution at different temperatures. METHODS： Twenty-four rabbit hearts were randomly divided into 3 groups： control group （group C, hypotherrnic hyperkalemic cardiac cardioplegia） and pinacidil pretreatment groups [ warm pretreatment group （WP） and cold pretreatment group （CP）, i.e., normothermic pretreatment and hypothermic pretreatment respectively]. Isolated rabbit hearts （group C） were perfused with oxygenated Krebs-Henseleits solution （K-H） by Langendorff apparatus for 10 min, followed with the standard 4℃ St. Thomas solution （ K^＋ 16 mmol/L at 37℃ ） cardioplegia. In group WP and group CP, when the hearts were perfused with K-H for 10 min, K-H solution containing pinacidil 10 μmol/L （37℃ in group WP, 4℃ in group CP） pretreatment was carried out before the standard St. Thomas （37℃ in group WP, 4℃ in group CP） was perfused. The hearts were subjected to 45 min ischemia （group C and group CP, 26 -28℃; group WP, 36 -38℃） and followed by 20 min reperfusion with 37℃ K-H solution. The time of heart arrest and rebeating, heart rate, heart rhythm, left ventricle pressure, left ventricle pressure （LVP）, myocardial adenylate and malondialdehyde （MDA） level were analyzed respectively. The myocardial structure of microscopic structure was determined. RESULTS： The time of heart arresting was not different in the 3 groups. The rate of rebeating after aortic unclamping was faster in pretreatment groups than that in group C （ P 〈 0. 05 ）, but it was significant different between the 2 pretreatment groups. Recoveries of left ventricle pressure and LVP were more rapid in group CP than those in group WP or group C （ P 〈 0. 05）. The recovery of LVP was better in group WP than that in group C （P〈0.05）. The levels of ATP, TAN and EC were the highest in group CP, the lowest levels in group C, and in-between in group WP. Myocardial microscope structure was the best in the group CP, then in group WP and group C in a descending order. MDA content was not significantly different in the 3 groups. CONCLUSION： Pinacidil pretreatment may remarkably enhance the myocardial protection against ischemia/reperfusion injury on the isolated hearts arrested with high potassium crystalloid and has a better protective effect on hypothermic cardiac cardioplegia.