Na^+通道阻滞极化停搏液在离体大鼠心脏保存中的保护作用

Protective effects of polarizing cardioplegia with Na+ channel inhibitor in ex vivo rat heart preservation

目的研究含Na+通道阻滞剂河豚毒素(TTX)极化停搏液在离体大鼠心脏保存中的心肌保护作用。方法20只Wistar大鼠随机均分入St.Thomas去极化停搏组(对照组,Ⅰ组)和TTX极化停搏组(Ⅱ组)。建立离体心脏灌注模型,灌注10min后,分别用St.Thomas和TTX极化停搏液2ml经主动脉插管注入,使心脏停搏。随后将鼠心置于相应配伍的停搏液中,10℃保存7h后重新灌注心脏30min。观察两组心脏保存前后在左心室收缩末压力和压力变化速率恢复率、心肌酶漏出、ATP含量和心肌超微结构等方面的改变。结果再灌注后,TTX极化停搏组血流动力学各项指标恢复率明显高于Ⅰ组(P<0.01),肌酸磷酸激酶和乳酸脱氢酶漏出量低于Ⅰ组(P<0.05),ATP含量维持在较高水平(P<0.01),心肌超微结构得到较好保护。结论在离体大鼠心脏低温保存过程中TTX极化停搏液心肌保护作用优于STH液。

Objective To investigate the protective effects of polarizing cardioplegia with Na^＋ channel inhibitor tetrodotoxin （TTX） in ex riro rat heart preservation. Methods Using a Langendorff preparation, Wistar rat hearts were arrested and preserved with St.Thomas （STH） solution （n=10） or with polarizing cardioplegia （TTX, n=10） for 7 h in hypothermic storage （10 ℃）. All the hearts then underwent 30 rain of reperfusion. Pre-ischemia and post-ischemia indexes of the rat hearts were determined, including the hemodynamic parameters, myocardial enzymology, ATP content and uhrastructural changes. Results The recovery of hcmodynamic parameters of the hearts in TTX group were better than those in STH group （P〈0.01）. In comparison with STH group, the leakage of creatine kinase （CK） and lactate dehydrogenase （LDH） in TTX group was significantly lower （P〈0.05） and ATP level maintained a relative high level with better protected myocardial ultrastructure. Conclusion TTX polarizing cardioplegia provides more effective long-term hypothermic preservation of isolated rat hearts than STH.