葡萄糖转运蛋白4在犬体外循环心肌胰岛素抵抗发生中的作用

目的 观察葡萄糖转运蛋白4(GLUT-4)在犬体外循环缺血再灌注心肌胰岛素抵抗(IR)发生中的作用.方法 将12条健康杂种犬随机分成组Ⅰ(主动脉阻断30 min),组Ⅱ(主动脉阻断120 min).分别于转流前、开放主动脉后15、45、75 min取左心室心肌活检用免疫组织化学法(Envision system)检测心肌GLUT-4,并用图像分析系统分析含量变化.结果 缺血再灌注后心肌GLUT-4总量表达明显下降,在缺血再灌注15 min最明显.缺血再灌注后心肌GLUT4由心肌细胞质向细胞外膜转运障碍,在再灌注15 min最明显,与组Ⅰ比较,组Ⅱ更重,持续更久(P＜0.05).结论 CPB缺血再灌注后心肌细胞GLUT-4表达总量下降及GLUT-4由心肌细胞质向细胞外膜转位障碍,可能是心肌胰岛素抵抗发生的重要分子机制之一.

Effect of glucose transportor-4 OR the myocardial insulin resistance in dogs undergoing cardiopulmonary bypass

Objective To investigate the role of glucose transportor-4(GLUT4)in the mechanism of myocardial insulin resistance during eardiopulmonary bypass(CPB)in dogs.Methods Twelve mongrel dogs subject to CPB were divided into two groups at random:group Ⅰ(n=6),aortic eross-clamping for 30 min and group Ⅱ(n=6),aortic cross-clamping for 120 min.The left ventricle samples were biopsied for immunohistochemical test before CPB,and 15 min,45 min and 75 min after reperfusion respectively.The changes of GLUT-4 content in myocardia were analyzed by using imaging analysis system.Results The totoal amount of GLUT-4 in myocardia was decreased most obviously at 15 min post-perfusion.As compared with group Ⅰ.recovery of GLUT-4 in group Ⅱ is less and costs mole time.Compared with not being perfused,discrepancy is eminent(P＜0.05).The obstacle of myocardium GLUT-4 transfer to extracellular membrance from cytoplasm is most obvious after being perfused 15 minutes later.Compared with not being being perfused,discrepancy is eminent(P＜0.05).Condusion The decrease in total ammout of GLUT-4 and its transfer obstacle from myocardium cytoplasm to perieellular melubrance may be the most important molecular mechanism which cause the myocardium insulin resistance.