两种心脏停搏液对兔未成熟乳头肌细胞电生理特性影响的对比研究

Experimental study of effects of MST and HTK cardioplagia on electrophysiologic properties of immature rabbit papillary muscles

目的 用标准玻璃微电极技术观察并记录两种心脏停搏液对兔未成熟乳头肌细胞电生理特性的影响。方法 实验选用 2～ 3周龄未成熟大耳白兔 19只 ,体重 (2 2 6 .47± 2 0 .0 6 )g ,随机分为MST组 (9只 )和HTK组 (10只 ) ,取左室乳头肌肌条 ,(36 .5± 0 .5 )℃台氏液平衡灌流 6 0min后 ,分别用 4℃改良St.Thomas液 (MST)和Bretschneider液 (HTK)灌流至停搏后 30min、再行台氏液复灌 6 0min。用标准玻璃微电极技术连续观察并记录乳头肌细胞电生理特性的改变。结果 MST组停搏时间、复灌后复跳时间均较HTK组短 ;停搏时静息电位 (RP)值、停搏期间最高RP值均较低 ,表现较好的能量储备 ;复灌后MST组静息电位、动作电位、超射值、0期最大除极速度、5 0 %复极化所需时间、90 %复极化所需时间的恢复比HTK组更早 ,提示良好的心肌保护效果。两组复灌后 2期平台期时程 (D2 )明显延长 ,与基础值比较差异有显著性。结论 MST液对兔未成熟乳头肌细胞电生理特性的保护效果优于HTK液。

Objective: The study was designed to evaluate the effects of different cardioplegia on immature papillary muscle cell electrophysiologic properties with standard glass microelectrode technique. Methods: Nineteen papillary muscles isolated from immature rabbit left ventriculars were randomly assigned to be perfused with modified St. Thomas cardioplegia (MST) and Histidine Tryprophane Ketoglutarate solution (HTK). The electrophysiologic properties were monitored in the whole process. The protocol were measured in the balance stage, cardioplegia perfusion and reperfusion phase. Resting potential (RP) was continuously observed in the program. Active potential (AP) data including active potential amplitude (APA), the increasing maximum rate of phase 0 depolarization (Vmax), overshoot (OS) and active potential duration(APD) were recorded. Results: Cardiac arrest time and re beat time of MST group was shorter than HTK group. RP in the cardioplegia perfusion phase was lower than HTK group. During reperfusion phase RP, APA, OS, Vmax, APD 50 , APD 90 of MST group recovered better than that of HTK group. But there was a significant difference of active potential 2 phase duration (D 2) during reperfusing than basic data; D 2 of HTK group were shorter than that of MST group. Conclusion: This study demonstrate that MST cardioplegia afford better protection on the cardiomyocyte electrophysiologic properties than HTK cardioplegia.