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Objective: To validate cardiopulmonary bypass ischemia reperfusion myocardial existence of the phenomenon of myocardial insulin resistance (IR) in observed IR process of myocardial GLUT-4 gene expression changes, to explore the mechanism of myocardial IR. Methods: According to the the cardiopulmonary bypass ascending aorta blocking different time were randomly divided into two groups. Group Ⅰ (n = 14), aortic clamping time ≤ 30min; Group Ⅱ (n = 14), aortic cross-clamping time> 30min. Bypass before CPB aortic occlusion (3min) open the aorta after 15min, 45min, 75 min, 2h, 4h, 8h when simultaneous acquisition artery, coronary sinus blood samples, corresponding time points of plasma glucose, insulin, glucagon, growth hormone, tumor necrosis factor-a (TNF-a), changes in free fatty acids. OPB before bypass and open aortic the 45min line right atrial myocardial biopsy, and determination of the right atrial tissue glycogen content, detected by RT-POR myocardial GLUT-4 gene expression changes at the same time, the content of the image analysis system . Results: 1. Myocardial glucose metabolism: ischemia reperfusion varying degrees of plasma glucose was significantly higher in reperfusion 15min, reached the peak, the difference was statistically significant (P <0.01) compared with aortic clamping. Myocardial glycogenolysis significantly enhanced significantly reduced reperfusion 45min myocardial glycogen before aortic clamping, the difference was statistically significant (P <0.01). Net myocardial glucose uptake [Glu (av) and net myocardial glucose uptake rate (%) [Glu (av)] / Glua at CPB ischemia-reperfusion after 15min, 45min are zero, compared with aortic occlusion The difference was statistically significant (P <0.01). Group Ⅰ, Ⅱ glucose concentrations, respectively reperfusion 2h hours after the close before aortic clamping levels. Reperfusion compared with group Ⅰ, group Ⅱ increased blood glucose concentration is more obvious, the difference was statistically significant (P <0.01), myocardial glucose uptake, the use of obstacles with group Ⅰ, group Ⅱ more serious, and lasts longer slower recovery, and the difference was statistically significant (P <0.05). Arterial blood glucose and coronary sinus blood glucose trend was consistent in the process of cardiopulmonary bypass myocardial ischemia-reperfusion. Insulin resistance index (IRI): the extracorporeal circulation myocardial ischemia-reperfusion process IRI were significantly higher, indicate the presence of significant IR reperfusion 15min, reached the peak, before aortic clamping, the difference was statistically significant ( P <0.01), in group Ⅰ IRI 75min basic recovery after reperfusion, group Ⅱ IRI 2h basic recovery after reperfusion. Compared with group Ⅰ, group Ⅱ after reperfusion, IRI elevated bigger, longer duration, speed of recovery is slower, and the difference was statistically significant (P <0.01). Plasma insulin, glucagon, plasma GH and TNF-a: ischemia and reperfusion in various stress hormones and TNF-a were significantly increased in the reperfusion 15min peak before aortic occlusion. The difference was statistically significant (P <0.05 or P <0.01). And 2h 8h between gradually restored to the level before aortic occlusion, the difference was statistically significant (P <0.05). Compared with group Ⅰ, group Ⅱ increased significantly, recovery is slower and last longer (P <0.05 or P <0.01); cardiopulmonary bypass bypass arterial and coronary sinus blood plasma FFA concentration to maintain a higher level, and then Plasma FFA concentration in a downward trend after perfusion, perfusion 45min group Ⅰ reduce the level of aortic occlusion compared, the difference was statistically significant (P <0.05) after reperfusion 75min group Ⅱ reduce the level of the aortic blocking before the difference was statistically significant (P <0.05). Between the two groups, and no significant difference in FFA concentration after reperfusion, no significant difference between the two sets of the same point in time arterial and coronary sinus plasma FFA concentration. Myocardial glucose transporter the protein-4mRNA express total 45min after ischemia and reperfusion, decreased aortic occlusion, the difference was statistically significant (P <0.01). The total group Ⅰ, group Ⅱ GLUT-4mRNA expression after reperfusion reduce more serious, and the difference was statistically significant (P <0.01). Conclusion: people extracorporeal circulation ischemia reperfusion body and myocardial IR phenomenon; CPB I / R myocardial IR process, glucagon, growth hormone, free fatty acids and TNF-α were significantly elevated may play a role to induce the body and myocardial IR; 3. extracorporeal circulation ischemia and reperfusion in cardiac myocytes GLUT-4 protein the GLUT-4mRNA total expression decreased during cardiopulmonary bypass GLUT-4 protein, GLUT-4mRNA decreased expression may be one of the important molecular mechanism of myocardial insulin resistance occurs.
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