缺血预处理在心瓣膜置换术中对心电活动及细胞缝隙连接的保护作用  

Effect of ischemic preconditioning on myoelectricity and the structure of myocardial gap junction during heart valve replacement surgery

作　　者：罗红鹤[1] 雷艺炎[1] 陈振光[1] 刘晓冰[2] 

机构地区：[1]中山大学附属第一医院胸心外科,广东广州510080 [2]深圳市孙逸仙心血管医院,广东深圳518001

出　　处：《中国病理生理杂志》2008年第10期1953-1956,共4页Chinese Journal of Pathophysiology

摘　　要：目的:从心肌细胞缝隙连接结构角度探讨缺血预处理(IP)在心脏瓣膜置换术中发挥保护作用的机制。方法:连续随机观察2004年4月-2004年12月接受心脏瓣膜置换手术治疗的患者54例,随机分成两组:IP组(n=22),主动脉阻断前实行单次缺血2min开放3min的IP方案,阻断主动脉后采用冷晶体心脏停搏液心肌保护进行手术;对照组(n=32),无缺血预处理,余步骤同IP组。观察两组术后心律失常发生、缝隙连接蛋白(Cx43)表达(免疫组化SABC法)以及电镜下心肌细胞结构及闰盘的变化。结果:IP组有1例(4.55%)发生室性心律失常(偶发室性早博);11例(50.00%)室上性心律失常(房颤、房扑、各种室上速、各种房室传导阻滞);有10例(45.50%)发生心肌缺血性ST-T段改变。对照组有14例(43.75%)发生室性心律失常(各种室性早博、心动过速);18例(56.25%)室上性心律失常;有28例(87.50%)发生心肌缺血性ST-T段改变,两组心律失常发生率有显著差异(P<0.05)。两组术前Cx43表达阳性单位无显著差异(P>0.05)。术后IP组为16.15±4.40,较术前无显著变化(P>0.05);对照组为11.92±1.26,较术前明显下降(P<0.05)。术后两组Cx43表达有显著差异(P<0.05)。电镜下观察:对照组闰盘不连接、紊乱、部分断裂,甚至完全断裂、崩解;心肌纤维也发生了大量坏死性结构改变:肌丝纤维肿胀,排列紊乱,肌丝Z线增宽,其它各带模糊,部分肌纤维溶解。IP组心肌细胞闰盘基本正常、连续,而心肌结构也基本正常。结论:IP维持了心肌缝隙连接蛋白Cx43的表达,具有保护细胞间缝隙连接结构和心肌电活动的正常传导作用。AIM： To investigate the cardio- protective mechanism of ischemic preconditioning （IP） during heart valve replacement of the perspective of architectural changes of myocardial gap junction. METHODS： Fifty - four patients were prospectively randomized to receive or not ischemic preconditioning before cold cardioplegic arrest. The IP protocol in IP patients （ n = 22 ） consisted of a single 2 - minute ischemia followed by 3 - minute reperfusion just before aortic clamping and cold crystalloid cardioplegia for myocardial protection. The control group （ n = 32 ） received no ischemic preconditioning prior to cold cardioplegic arrest. The parameters including arrhythmias occurrence, Cx43 expression （ immunohistochemistry SABC method） and myocardial structure and intercalated discs observed under electronic microscope were recorded before and after surgery in each group. RESULTS： In IP group, one case （4. 55% ） of ventricular arrhythmia （ sporadic ventricular premature beat） , 11 cases （ 50.00% ） of supraventricular arrhythmia （ atrial fibrillation, atrial flutter, supraventricular tacbycardia, atrioventricular block） and 10 cases （45.50%） of ischemie ST - T changes were observed. In control group, there were 14 cases （43.75%） of ventricular arrhythmia （ventricular premature beat, tachycardia） , 18 cases （56. 25% ） of supraventricular tachycardia and 28 cases （87. 50% ） of ischemic ST - T changes. No statistical difference in preoperative positive unit of Cx43 expression between the two groups was found （ P 〉 0.05 ）. Postoperatively, the positive unit of Cx43 expression in IP group was 16. 15 ±4. 40, but the difference was not significant compared to the preoperative value （ P 〉 0. 05 ）. In control group, Cx43 expression was 11.92±1.26, significantly lower than that of the preoperative value （ P 〈 0. 05 ）. Cx43 expression between the two postoperative groups showed a significant difference （P 〈 0. 05 ）. In control group, electronic microsc

关 键 词：缺血预处理 连接蛋白43 缝隙接合部 心脏瓣膜手术 

分 类 号：R542.5[医药卫生—心血管疾病]