模拟缺血再灌注后心肌细胞胰岛素抵抗机制的初步研究  

Mechanisms of insulin resistance during ischemia reperfusion in the cardiomyocytes of rat

作　　者：李勇刚[1] 陈焕文[1] 张尔永[1] 隋东虎[1] 石应康[1] 

机构地区：[1]四川大学华西医院心胸外科,成都610041

出　　处：《中华胸心血管外科杂志》2009年第3期190-192,共3页Chinese Journal of Thoracic and Cardiovascular Surgery

基　　金：本课题受国家自然科学基金资助（30270567）

摘　　要：目的初步探讨缺血再灌注后心肌细胞胰岛素抵抗现象的分子机制。方法建立成年大鼠心肌细胞模拟缺血再灌注模型，应用同位素示踪技术评价心肌细胞的胰岛素敏感性。Westernblot分析检测心肌细胞葡萄糖转运蛋白4（GLUT4）的转位。荧光分光光度仪测定模拟缺血再灌注心肌细胞游离钙离子浓度（[Ca^2＋]i）。结果模拟缺血再灌注心肌细胞表现出明显的胰岛素抵抗。胰岛素刺激再灌注心肌细胞的GLUT4转位较对照组明显降低（P〈0．05）。同时，模拟缺血再灌注心肌细胞[Ca^2＋]i显著高于对照组[（318．66±23．06）对（130．70±10．82）nmol／L，P〈0．05]，至再灌注60min仍高于对照组（P〈0．05）。偏相关分析显示，[Ca^2＋]i与胰岛素刺激的葡萄糖摄取呈负相关（r=-0．557，P=0．006）。结论胰岛素刺激的GLUT4转位障碍和内在活性的降低是模拟缺血再灌注心肌细胞胰岛素抵抗的重要分子机制，[Ca^2＋]i超载可能是缺血再灌注心肌GLUT4内在活性降低的重要原因。Objective Recent studies have found a strong association of insulin resistance, which might occur during ischemia reperfusion in vitro in the experimental dogs, with disturbed function of cardiomyocytes. Obvious acute insulin resistance, along with glucose dysmetabolism in the reperfused cardiomyocytes, was further observed in the study performed with ischemia-reperfused ventricular myocytes of rats. We tried to investigate preliminarily the molecular mechanisms of insulin resistance in the cardiomyocytes after ischemia reperfusion. Methods An experimental model of insulin-stimulated ischemia reperfusion （SI/R） was created by isolating cardiomyocytes from adult rats. Glucose uptake of the cardiomyoctyes was evaluated with isotepe-labeling technique. Glucose transporter 4 （GLUT4） translecafion induced by insulin was investigated with Western blot analysis, and the intracellular level of free Ca^2 ＋ （[ Ca^2 ＋ ]i） was measured quantitatively with Ca^2 ＋ indicator Fura-2. Results Insulin can stimulated glucose uptake by cardiomyocytes, indicating that these cells were insulin-sensitive. Cardiomyocytes were demonstrated notable acute insulin resistance during reperfusion.Insulin-stimulated GLUT4 translocation in the cardiomyocytes 15 minutes after reperfusion was 72.2% of that in the control group（ P 〈 0.05）, in which the GLUT4 content in plasma membrane remained ybchanged. The finding suggested that a dissturbed GLUT4 translocafion might happen in the cardiomyocytes during insulin-stimulated ischemia-repeffusion. Calcium overload was identified in the cardiomyocytes with ischemia reperfusion. At 15 minutes of reperfusion, [ Ca^2 ＋ ]i was significantly higher in the reperfused cardiomyceytes than that in the control cardiomyocytes[ （318.66 ± 23.06） vs （ 130.70 ± 0.82） ninol/L, P 〈 0.05 ], and kept at a higher level[（177.79 ± 17.46）nmol/L]at 60 minutes of reperfusion （ P 〈0.05, vs control）. Partial correlation analysis revealed a negative correlation of [ Ca^2 ＋ ]i wit

关 键 词：心肌再灌注损伤 胰岛素 葡萄糖 钙 

分 类 号：R686[医药卫生—骨科学]