The Effects Of Cardiopulmonary Bypass On Autophagy Level And Survival Rate Of Nuetrophil In Children

The aim of this paper was to study the effects on neutrophil autophagy level and survival rate of neutrophil induced by CPB(cardiopulmonary bypass)in children undergoing open heart surgery of VSD(ventricular septal defect)repair.12 children scheduled to receive VSD repair under cardiopulmonary bypass and 12 children scheduled to receive minimally invasive closure of VSD under ultrasound guidance were recruitment into CPB group and N-CPB group,respectively.5mL of blood was sampled and the neutrophils were isolated with density gradient centrifugation method for each of the children at time point of T0(after induction of anesthesia)and T1(after CPB/post occluder placement).The autophagy-related proteins Beclin-1?LC3-II and p62 of neutrophil were detected by Western blot.Real-time reverse transcription PCR(RT-qPCR)was used to measure the mRNA expression level of autophagy-related gene Atg-5.The result shows that the Beclin-1 and LC3-II expression levels were increased at T1 when compared with T0 in CPB group(P<0.05),but there were no significant changes in N-CPB group;no expression of P62 was detected in the T0 and T1 groups;compared with T0,the expression of neutrophil Atg-5 at T1 in the CPB group was reduced(P <0.05),but there was no significant change in the N-CPB group.After that,other 6 children scheduled to receive VSD repair under cardiopulmonary bypass were enrolled,and the blood was sampled at before and after CPB(T0 and T1),and the neutrophil were isolated similar to the former.Each neutrophil sample was divide into 2 parts,one go into control group and another go into 3-MA(3-methyladenine,autophagy inhibitor)group.The neutrophil survival rate was observed with trypan blue staining at 0,1,2,4,and 8 h.Subsequently,the neutrophil survival rate of T1 was significant increased at 0 h and 1 h when compared with T0(P<0.05).In the 3-MA group,the survival rate of neutrophil was decreased rapidly at 1,2,4,and 8 h when compared with 0 h(P<0.05).When compared with control group,the neutrophil survival rate in 3-MA group were significant decreased at 2,4 and 8 h(P<0.05).The study showed that CPB increased neutrophil autophagy protein levels in children with ventricular septal defect repair,and may reduce the expression of autophagy genes through feedback regulation.Second,neutrophil survival time was extended after CPB,and Inhibition of autophagy can shorten cell survival time.