ATP敏感性钾离子通道开放剂二氮嗪对布比卡因致大鼠心肌细胞毒性作用的影响

Effect of ATP-sensitive potassium channel opener diazoxide on bupivacaine-induced cardiotoxicity in rats

目的评估二氮嗪对布比卡因心肌抑制的影响,观察布比卡因对心肌细胞的直接毒性作用,以及使用二氮嗪是否可以减轻或消除此毒性作用。方法选择成年SD大鼠50只,通过主动脉逆行灌流酶解法行急性心肌细胞分离,待细胞分离成功后,每只大鼠分别选取杆状、条纹清晰、边缘整齐的心肌细胞,采用随机数字表法分为两组:布比卡因组(Bup组)和二氮嗪+布比卡因组(Bup+D组);各组中按布比卡因浓度不同又分为5个亚组,分别为Bup1、Bup2、Bup3、Bup4、Bup5组和Bup+D1、Bup+D2、Bup+D3、Bup+D4、Bup+D5组,对应布比卡因浓度分别为20.0、30.0、45.0、67.5、101.5μmol/L。记录给予各组中不同浓度布比卡因灌流前后细胞有无停止自发性搏动,并记录再次更换有钙台氏液后细胞有无恢复自发性搏动。结果除20μmol/L外,给予二氮嗪和不同浓度布比卡因灌流后,各组心肌细胞衰竭率显著低于给予单纯布比卡因灌流(P<0.05)。二氮嗪+布比卡因所致大鼠心肌细胞衰竭的半数最大效应浓度(EC50)及其95%CI为64.6(47.4~84.3)μmol/L,明显高于单纯布比卡因所致[44.9(33.9~55.4)μmol/L,P<0.05];衰竭的细胞停止灌流布比卡因和二氮嗪后,细胞均可恢复正常收缩状态。结论布比卡因的心脏毒性与其线粒体ATP敏感性钾离子通道(mitoKATP)抑制作用有关,开放ATP敏感性K离子通道可显著提高大鼠心肌耐受布比卡因心肌毒性的能力。

Objective In order to evaluate the effect of diazoxide on myocardial inhibition of bupivacaine,observe the direct toxic effect of bupivacaine on myocardial cells,and whether the use of diazoxide can reduce or eliminate this toxic effect.Methods Fifty adult SD rats were selected and subjected to aortic retrograde perfusion enzymolysis for acute cardiomyocyte isolation.After the cells were successfully isolated,the cardiomyocytes with rod-shaped,clear stripes and regular edges were selected and divided into two groups by random number table method:bupivacaine group(Bup group) and diazoxide + bupivacaine group(Bup+D group).Both group were divided into 5 subgroups according to different bupivacaine concentrations(20.0,30.0,45.0,67.5,and 101.5 μmol/L),respectively.Whether the cells stopped spontaneous beating before and after perfusion with different concentrations of bupivacaine,and whether the cells resumed spontaneous beating after changing the calcium Tyrode′s solution again were recorded.Results Except for 20.0 μmol/L,after perfusion with diazoxide and bupivacaine at different concentrations,the rate of myocardial cell failure in each group was significantly lower than that given with bupivacaine perfusion alone(P<0.05).The EC50 and 95%CI diazoxide+bupivacaine-induced myocardial cell failure in rats was 64.6(47.4-84.3)μmol/L,which was significantly higher than that induced by bupivacaine alone[44.9(33.9-55.4)μmol/L,P<0.05].After the failed cells stopped perfusion of bupivacaine and diazoxide,the cells could return to normal contraction.Conclusions The cardiotoxicity of bupivacaine is related to its inhibition of mitochondrial ATP-sensitive potassium channel(mitoKATP),opening ATP-sensitive K channels can significantly improve the ability of rat myocardium to tolerate myocardial toxicity of bupivacaine.