极化心脏停搏液对成熟心肌细胞保护作用的研究

目的观察Na＋通道阻滞剂河豚毒素（TTX）极化心脏停搏液对离体成熟大鼠心肌细胞Na＋]i、Ca2＋]i的影响,探讨其对成熟心肌细胞的保护作用。方法成年Wistar大鼠心脏,用酶解法分离成具有搏动性的单个成熟心室肌细胞悬液,随机分成基础组、STH2组（对照组）和TTX组（实验组）,STH2组和TTX组分别应用St.Thomas II号停搏液和TTX停搏液处理,建立模拟缺血/再灌注损伤的停搏/复搏细胞模型,激光扫描共聚焦显微镜（LSCM）测定各组细胞不同时期的Na＋]i和Ca2＋]i。结果 TTX组和STH2组成熟心肌细胞复搏后Na＋]i、Ca2＋]i均明显高于基础组（P〈0.01）,但TTX组明显低于STH2组（P〈0.01）。结论极化心脏停搏液较去极化心脏停搏液能减轻成熟心肌细胞Na＋、Ca2＋超载,对成熟心肌细胞有较好的保护作用。

Protective effects of cardioplegia with tetrodotoxin on mature cardiomyocytes

Objective To investigate the Effects of polarizing cardioplegia solution with sodium channel inhibitor tetrodotoxin（TTX） through observating the intracellular free Na＋ concentration（i） and Ca2＋ concentration（i）in isolated cardiomyocytes of mature rat.Methods Mature ventricular myocytes with beating were isolated from adult rat hearts by enzymatic dissociation,randomly created in Group Base,Group STH2（contrast group of ischemia/reperfusion） and Group TTX（treated group）.Both Group STH2 and Group TTX were arrested by St.Thomas No.2 cardioplegia solution and TTX cardioplegia solution respectively,the arrest/re-beating cell model imitating MIRI being established,and imaged by laser scanning confocal microscopy（LSCM） for measuring i and i of cardiomyocytes in different period.Results i and i of mature cardiomyocytes in both Group TTX and Group STH2 after re-beating was higher than that in Group Base（P0.01）,i and i in Group TTX was lower than that in Group STH2（P0.01）.Conclusion Contrast depolarized cardioplegia solution,polarized cardioplegia solution could alleviate ischemia reperfusion injury and intracellular Na＋ and Ca2＋ overload of mature cardiomyocytes.