左卡尼汀强化St.Thomas No.2液对长时间冷保存离体心脏能量代谢的影响

目的 探讨不同剂量的左卡尼汀（LCN）添加至St.Thomas No.2液后对长时间冷保存离体大鼠心脏能量代谢的影响.方法 利用Langendorff灌注装置建立离体大鼠心脏模型.SD大鼠56只随机分为4组：对照组8只、St组16只（该组使用St.Thomas No.2液为心脏停搏液和保存液）、LCN 1组16只（St.Thomas No.2液加LCN 12g/L为心脏停搏液和保存液）和LCN 2组16只（St.Thomas No.2液加LCN 6g/L为心脏停搏液和保存液）.对照组直接取左心室心肌组织,其他各组16只大鼠中8只在4℃条件下保存心脏7h后取左心室心肌,另外8只建立离体左心工作模型,再灌注30min后取左心室心肌.检测心肌三磷酸腺苷（ATP）、二磷酸腺苷（ADP）、一磷酸腺苷（AMP）、总腺苷（TNA）含量并计算能荷（EC）;提取心肌线粒体后检测线粒体内Ca^2＋含量（Ca^2＋]m）及线粒体呼吸功能.结果 St组冷保存后心肌ATP含量和EC显著下降,Ca^2＋]m显著增高,线粒体呼吸控制率（RCR）明显降低（P〈0.05）;再灌注后心肌ATP含量及EC无明显改善,Ca^2＋]m进一步增高,RCR进一步降低（P〈0.05）.LCN 1组及LCN 2组各项指标较St组显著改善（P〈0.05）,两治疗组之间比较差异亦有统计学意义.结论 不同剂量的左卡尼汀添加至St.Thomas No.2液可减轻线粒体钙超载,改善心肌能量代谢,对心肌细胞线粒体有较好的保护作用.此保护作用与LCN剂量有关.

Experimental study of St.Thomas No.2 solution supplemented with L-carnitine on myocardial energy metabolism of prolonged hypothermic preservative rat hearts

Objective To investigate the protective effects of St. Thomas No.2 solution supplemented with L-carnitine （LCN）on myocardial energy metabolism of prolonged hypothermic preservative rat hearts. Methods Isolated rat heart Langendorff model and working model were established. Fifty-six Sprague-Dawley rats were divided into 4 groups randomly： Control group,St group （St.Thomas No.2 solution）,LCN1 group （St.Thomas No.2 solution supplemented with LCN 12 g/L ） and LCN2 group（St.Thomas Ⅱ solution supplemented with LCN 6 g/L）. There were eight rats in the control group, and sixteen in each of the other groups. In St,LCN1 and LCN2 group, 8 hearts were stored at 4 ℃ organ preservation solution for 7 h, and another 8 hearts were reperfused for 30 rain after stored for 7 h. ATP, ADP, AMP contents of myocardial were determined and energy charges （EC） were calculated. The mitoehondrial Ca^2＋ concentration （ Ca^2＋ ]m） and respiration function were determined. Results Compared with control group, after stored in 4 ℃ organ preservation solution for 7 h or reperfused for 30 min, the content of myocardial ATP, EC and mitochondrial respiratory control rate （RCR） in St group decreased, and Ca^2＋ ]m increased significantly （P〈0.05）. LCN1 group and LCN2 group had better results than St group. The parameters of LCN1 were better between the other two groups. Conclusion Mitochondria were severely injured after prolonged hypothermic heart preservation, leading to the disorder of myocardial energy metabolism which can be alleviated by St. Thomas No.2 solution supplemented with L-carnitine and the effect of L-carnitine 12 g/L is better than that of L-carnitine 6 g/L.