七氟醚后处理对离体大鼠心脏再灌注心律失常的影响

Effects of sevoflurane postconditioning on reperfusion arrhythmia in isolated rat hearts

目的探讨七氟醚后处理对离体大鼠心脏再灌注心律失常的影响。方法雄性sD大鼠，2．5月龄，体重250～300g，Langendorff装置制备离体心脏灌注模型30个，采用随机数字表法，将其随机分为3组（n=10）；对照组（c组）、缺血再灌注组（I／R组）和七氟醚后处理组（s组）。c组继续灌注K—H液55min；I／R组和s组均停止灌注K-H液25min，随后I／R组再灌注K-H液30min；S组在再灌注初期灌注3％七氟醚饱和的K—H液15min，然后灌注K—H液15min。分别于缺血前（基础状态）、再灌注15、30min时记录左室发展压（LVDP）、左室舒张末期压力（LVEDP）、左室内压上升最大速率（＋dp／dtmax）、左室内压下降最大速率（-dp／dtmin）和心率（HR），并记录再灌注期间心律失常的发生情况。于再灌注结束时收集冠脉流出液，测定心肌肌钙蛋白I（cTnI）水平；然后取心尖部组织，测定心肌细胞内游离钙离子浓度（[Ca^2＋]i）。结果与c组比较。I／R组LVDP、＋dp／dtmax、-dp／dtmin和HR降低，LVEDP、cTnI浓度和[Ca^2＋]i升高（P〈0．05）；与I／R组比较，s组LVDP、＋dp／dtmax、-dp／dtmin和HR升高，LVEDP、室性早搏数量、室颤发生率、再灌注心律失常评分、cTnI浓度和[Ca^2＋]i降低，室性心动过速时程和室颤时程缩短（P〈0．05）。结论七氟醚后处理可降低离体大鼠心脏再灌注心律失常的发生，其机制与减轻细胞内钙超载有关。

Objective To investigate the effects of sevoflurane postconditioning on reperfusion arrhythmia in isolated rat hearts. Methods Male SD rats weighing 250-300 g were heparinized and anesthetized with intraperitoneal urethane 1.5 g/kg. Their hearts were rapidly excised and perfused in a langendorff apparatus with oxygenated （95 % O2-5 % CO2 ） K-H solution at 10 ml/min. After 15 min of stabilization the isolated hearts were randomly divided into 3 groups： group control （group C）; group I/R -- perfusion was suspended for 25 rain followed by 30 rain reperfusion, and group sevotlurane postconditioning （group S） -- the isolated hearts were reperfused after 25 inin of no flow ischemia first with K-H solution saturated with 3% sevoflurane for 15 rain followed by 15 min reper- fusion with K-H solution without sevoflurane. Left ventrieular developed pressure （LVDP）, left ventricular end-diastolie pressure （LVEDP）, ＋ dp/dt -dp/dt,m., HR, ECG, eardiac troponin I （eTnI） concentration in coronary effluent and intracellular Ca2 ＋ level were measured. Results Myocardial I/R significantly decreased LVDP, ＋ dp/dt - dp/dtmi, , and HR and increased LVEDP, cTnI concentration in coronary effluent and intracellular Ca^2＋ level in group I/R as compared with group C. Sevoflurane postconditioning significantly attenuated I/R-induced hemodynamie changes and increase in cTnI concentration in coronary effluent and intracellular Ca^2＋ level in group S compared to group I/R. Conclusion Sevoflurane postconditioning can ameliorate reperfusion arrhythmia in isolated rat hearts by inhibiting intracellular Caz~ overload.