The Expression And Significance Of APPL1 In Myocardial Ischemia-reperfusion Injury During Human Cardiopulmonary Bypass

Objective: To investigate the expression and significance of APPL1 in myocardial ischemia-reperfusion injury during human cardiopulmonary bypass.Methods: According to the time of aortic occlusion,40 children with congenital heart disease undergoing cardiopulmonary bypass were divided into two groups with 20 children in each group.The time of aortic occlusion in group A was less than 30 min,and that in group B was more than 30 min.Blood samples were taken from the artery and vein for 3 ml at T1(3 minutes after bypass,before cross-clamp of ascending aorta),T2(15 minutes after the opening of the ascending aorta)and T3(45 minutes after the opening of the ascending aorta)during the surgery.The concentration of glucose,free fatty acid,insulin,adiponectin and troponin in blood samples were measured,and the myocardial glucose intake,free fatty acid intake and insulin resistance index were calculated.At T1 and T3 time points,myocardial tissue of right auricle was collected.The expression of APPL1,APN and AdipoR1 in integral optical density was observed by immunohistochemistry,and the mRNA expression of APPL1,APN and AdipoR1 in myocardium was detected by qRT-PCR.Results: 1.Changes of Troponin I: There was no significant difference in plasma troponin I between group A and B at T1 time point.At T2 and T3 time points,the plasma troponin I of group B was significantly higher than group A(P < 0.05).Compared with T1 time point in the same group,troponin concentration at T2 and T3 time point was significantly higher(P < 0.05).2.The changes of glucose and fatty acid metabolism: Compared with T1 time point,the concentration of glucose and fatty acid in the arterial and venous plasma of T2 and T3 time point were significantly higher(P < 0.05);There was no significant difference in the content of glucose and fatty acids between group A and group B at T1 time point,but the content of glucose and fatty acids of group B was significantly higherthan that in group A at T2 and T3 time points(P < 0.05).3.Insulin concentration and insulin resistance index: Compared with T1 time point,the plasma insulin concentration and insulin resistance index in T2 and T3 time points were significantly higher(P < 0.05).There was no significant difference in plasma insulin concentration and insulin resistance index between group A and group B at T1 time point,but it's significantly higher in group B than in group A at T2 and T3 time points(P < 0.05).4.Changes of plasma APN concentration: Compared with T1 time point,the plasma APN concentration in T2 and T3 time points was significantly lower(P < 0.05).There was no significant difference in APN concentration between group A and group B at T1 time point,but it's significantly lower in group B than in group A at T2 and T3 time points(P < 0.05).5.The expression of APPL1,APN and AdipoR1 mRNA in cardiomyocyte: Compared with group A,there was no significant difference in the expression of APN,AdipoR1 and APPL1 in group B at T1 time point,but the expression of APN,AdipoR1 and APPL1 was lower at T3 time point(P < 0.05);compared with T1 time point,the expression of APN,AdipoR1 and APPL1 in group A and B were significantly decreased(P < 0.05).6.The expression of APN,AdipoR1 and APPL1 in integral optical density observed by immunohistochemistry: The IOD value of APN,AdipoR1 and APPL1 in T3 time point was significantly lower than that in T1 time point(P < 0.05).Compared with group A,the IOD value of group B was lower,the difference was statistically significant(P < 0.05).Conclusion: After MIRI in human cardiopulmonary bypass,the expression of APPL1 in myocardial tissue is reduced,and the resulting disorder of FFA metabolism may be one of the causes of myocardial IR.