体外循环缺血—再灌注后心肌胰岛素抵抗现象的初步研究

目的 求证体外循环缺血－再灌注后存在心肌胰岛素抵抗现象的假设。方法 12条雄性杂种狼犬，按体外循环升主动脉阻断时间的不同分为两组，组I（n=6)；主动脉阻断25分钟：组Ⅱ（n=6)；主动脉阻断150分钟、分别于转流前、主动脉开放后10分钟、30分钟和60分钟测定冠状静脉窦血流量和血流动力学，并同时采集动脉和冠状静脉窦血测定血浆葡萄糖、乳酸、胰岛素、C肽、胰高血糖素、皮质醇和生长激素浓度的动态变化。结果 缺血－再灌注后血浆葡萄糖、乳酸、胰岛素、C肽、胰高血糖素、皮质醇和生长激素浓度与转流前比较均有不同程度的明显增高，再灌注10－30分钟达峰值（Ｐ＜０．０５），同时心肌对葡萄糖的摄取、利用有严重障碍。与组１比较，组Ⅱ上述系列化指标均明显增高，且心肌葡萄糖摄取、利用障碍持续时间更长，停机后心功能明显下降。结论 在体外循环缺血－再灌注机体胰岛素抵抗同时，亦存在明显的心肌胰岛素抵抗现象，其程度随体外循环时间延长而增强，并与心功能障碍的发生密切有关。

A Preliminary Study on the Phenomenon of Myocardial Insulin Resistance after Ischemia-reperfusion with Extracorporeal Circulation

Objective To test the hypothesis of myocardial insulin resistance phenomenon after ischemia-reperfusion with extracorporeal circulation(ECC). Methods Twelve male mongrel wolf dogs underwent ECC were divided into two groups:group Ⅰ(n=6), aortic cross-clamping for 25min and group Ⅱ(n=6), aortic cross-clamping for 150 min. Coronary sinus blood flow and systemic hemodynamics, and the plasma concentrations of glucose, lactate, insulin, C-peptide, glucagon, cortisol, growth hormone as well as the myocardial net extraction and percent extraction of glucose and lactate were detected at pre-bypass, reperfused 10min, 30min and 60min respectively.Results After myocardial ischemia-reperfusion,the plasma concentrations of glucose, lactate, insulin, C-peptide, glucagon, cortisol and growth hormone were all significantly increased and reached their peak levels during reperfused 10min and 30min in comparison with pre-bypass level (P＜0.05), meanwhile myocardial dysfunction with no extraction of glucose. In comparison with group Ⅰ:the biochemical variables mentioned above in group Ⅱ were markedly increased, while myocardial dysfunction with no extraction of glucose lasted longer time and cardiac function significantly decreased after weaning from ECC. Conclusion Accompanied with typical peripheral insulin resistance, the phenomenon of myocardial insulin resistance significantly exists after myocardial ischemia-reperfusion with ECC. The increased extent of myocardial insulin resistance relies upon the duration of ECC, and is closely associated with heart dysfunction.