右美托咪啶预处理对大鼠离体心脏缺血再灌注损伤的影响

目的 评价右美托咪啶预处理对大鼠离体心脏缺血再灌注损伤的影响.方法 健康清洁级雄性Wistar大鼠24只,体重230～ 260 g,制备离体Langendorff心脏灌注模型后,采用随机数字表法,将离体心脏随机分为3组(n=8):缺血再灌注组(I/R组)、右美托咪啶Ⅰ组(DI组)、右美托咪啶Ⅱ组(DⅡ组).各组均先用K-H液平衡灌注10 min后,I/R组用K-H液继续灌注30 min,D I组和DⅡ组分别用含有0.23.、2.30ng/ml右美托咪啶的K-H液继续灌注20 min,再用K-H液冲洗10 min.各组心脏均缺血30 min,K-H液再灌注120 min.于平衡灌注末、再灌注5、30、60和120min时收集冠脉流出液,测定肌酸激酶(CK)和乳酸脱氢酶(LDH)活性.再灌注末取心肌组织,测定SOD活性及MDA含量.结果 与I/R组比较DⅠ组和DⅡ组冠脉流出液CK、LDH活性、心肌组织MDA含量降低,心肌组织SOD活性升高(P＜0.05)；与DI组比较,DⅡ组冠脉流出液CK、LDH活性、心肌组织MDA含量降低,心肌组织SOD活性升高(P＜0.05).结论 右美托咪啶预处理可减轻大鼠心肌缺血再灌注损伤,且与浓度有关.

Effects of dexmedetomidine preconditioning on ischemia-reperfusion injury to isolated rat hearts

Objective To investigate the effects of dexmedetomidine preconditioning on ischemia-reperfusion(I/R) injury to isolated rat hearts.Methods Twenty-four male Wistar rats weighing 230-260 g were anesthetized with intraperitoneal 10％ chloral hydrate 400 mg/kg and heparin 500 IU/kg.Their hearts were excised and perfnsed in a Langendorff apparatus with K-H solution saturated with 95％O2-5％CO2 at 37 ℃.Twenty-four isolated rat hearts were randomly divided into 3 groups after 10 min of equilibration(n =8 each):group I/R,dexmedetomidine 0.23,2.30 ng/ml preconditioning group (groups D I,D Ⅱ ).In group I/R,the hearts were perfused continuously for another 30 min.In groups D Ⅰ and D Ⅱ,the hearts were perfused with K-H solution containing dexmedetomidine 0.23,2.30 ng/ml for 20 min followed by 10 min washout before ischemia.All hearts were subjected to 30 min of global ischemia followed by 120 min of reperfusion with K-H solution.The activities of creatine kinase(CK) and lactate dehydrogenase(LDH) in coronary effluent were measured at the end of 10 min equilibration(balance),and at 5,30,60 and 120 min of reperfusion.Myocardial tissues were obtained at the end of reperfusion for determination of the activity of SOD and the content of MDA.Results Compared with group I/R,the CK and LDH activities in coronary effluent and MDA content in myocardium were significantly decreased,the SOD activity was significantly increased in groups D I and D Ⅱ ( P ＜ 0.05).Compared with group D Ⅰ,the CK and LDH activities in coronary effluent and MDA content in myocardium were significantly decreased,the SOD activity was significantly in group DⅡ ( P ＜ 0.05).Conclusion Dexmedetomidine preconditioning can attenuate myocardial I/R injury in a concentration-dependent manner in rats.