The Effects of Cardiopulmonary Bypass on Autophagy Level and Survival Rate of Nuetrophil in Children
YI Han, YANG Taobo, SONG Juan, WANG Xiaoyan, XIAO Zongyi, WANG Shouyong*
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. 5 mL 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 and LC3-II of neutrophil were detected by Western blot. 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. 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 present investigation implicated that cardiopulmonary bypass can increase the autophagy level and survival rate of neutrophil in children undergoing open heart surgery of VSD repair, and inhibiting the autophagy level induces rapid death of neutrophil after CPB.
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