Effect of cardiopulmonary bypass on insulin signal transduction pathway of islet cells in rabbits

Abstract

Objective To observe the effect of cardiopulmonary bypass (CPB) on insulin signal transduction pathway of islet cells in rabbits and investigate the potential mechanism of hyperglycemia in CPB.Methods New Zealand rabbits were divided randomly into sham operation (S) group and CPB group.The arterial blood samples of rabbits in the two groups were collected and determined for blood glucose by glucometer and for insulin and glucagon by radioimmunoassay.The expression levels of insulin,glucagon and IRS-1 in pancreatic islets were detected by using immunofluorescence assays.Results As compared with the data immediately before CPB (0.106 ±0.005),the expression of INS in islets at 75 min after reperfusion (0.120 ±0.011) was significantly increased,and the expression of IRS-1 in islets immediately after aortic cross-clamping (0.074 0.008) was higher than that immediately before CPB (0.069 ±0.005) in CPB group (P ＜0.05).As compared with the data immediately before CPB (0.095 ±0.010),the expression of GLC in islets was significantly decreased after reperfusion (0.073 ± 0.015,0.065 ±0.0l3,0.053 ± 0.007) in CPB group (P ＜ 0.05).Conclusion The inhibitory effect of CPB on the increase of IRS-1 expression in islets of rabbits in CPB group may be one reason why the increased insulin could not meet the needs of compensatory function. Key words: Cardiopulmonary bypass; Islet cells; Insulin resistance