虎杖苷对严重烫伤大鼠心肌细胞钙信号调控的作用

目的：观察虎杖苷（polydatin，PD）对烫伤大鼠心功能损害的钙信号调控，并探讨其对烫伤大鼠心肌细胞保护作用的机制。方法：28只成年SD大鼠随机分为4组，即假手术组、烫伤组、PD组及烫伤＋PD组，每组7只大鼠（n=7）。 各实验组使用Power lab系统进行实时心功能监测。手术后5 min通过静脉给予PD（10 mg/kg）,12 h后分离心室肌细胞，通过激光共聚焦显微镜观测PD对烫伤大鼠心室肌细胞钙火花发放频率、钙库水平、钙瞬变的作用。结果：与烫伤组比较，烫伤＋PD组大鼠左室收缩压、左心室内压力上升的最大速率（±dP/dtmax）均显著增加、钙瞬变和心肌收缩力明显增强、使烫伤引起的钙库容量下降基本恢复到正常水平，烫伤引起的高频钙火花发放显著抑制（均P〈0.01），钙火花时程的增加也明显抑制（P〈0.05）。结论： PD可以显著抑制烫伤引起的心肌细胞肌浆网钙漏流，恢复肌浆网钙库容量水平，增强收缩期钙瞬变和心肌收缩力，从而改善烫伤引起的心功能障碍。

Polydatin modulates calcium signals in thermally injured cardiomyocytes

AIM：To investigate the protective effect of polydatin （PD） on calcium signals in thermally injured cardiomyocytes. METHODS： Twenty eight adult Sprague Dawley rats were randomly divided into four groups （seven rats/group）： sham operation group, thermal injury group, PD group and thermal injury＋PD group. Polydatin （10 mg/kg） was given intravenously 5 min after operation. Twelve hours after thermal injury, single myocytes were isolated from ventricular free wall enzymatically and loaded with Ca2＋ indicator fluo 4 AM. Ca2＋ sparks and transients were recorded. RESULTS： PD significantly improved left ventricular systolic pressure （LVSP）, ＋dP/dtmax and dP/dtmax of thermal injury cardiomyocytes （P〈0.01）. Polydatin significantly increased thermal injury systolic Ca2＋ transients by about 26% and myocyte contractility （P〈0.01）, restored sarcoplasmic reticulum Ca2＋ content （P〈0.01）, inhibited thermal injury induced high frequency and the duration of calcium sparks （P〈0.05）. CONCLUSION： Polydatin has the capability of preventing SR leak and restoring intracellular Ca2＋ homeostasis in thermal traumatized hearts and ameliorates thermally induced cardiac dysfunction, thus exerting strong therapeutic effect against burn generated cardiac dysfunction.