Effects of Plasma Extracted from Cardiopulmonary Bypass on the Chemotaxis and CXCR4 Expression in Neutrophil-Like Cells

Abstract: The aim of this paper was to study the effects of plasma extracted from cardiopulmonary bypass children on the chemotaxis and CXCR4 expression in neutrophil-like cells in vitro. 12 children scheduled to receive ventricular septal defect (VSD) closure under cardiopulmonary bypass (CPB) (CPB group) and 12 children scheduled to receive minimally invasive closure of ventricular septal defect (VSD) with ultrasound guidance (N-CPB group) were enrolled. The blood was sampled and plasma were collected at before and after surgery. The chemotaxis of neutrophil-like cells (NLC) to the N-CPB or CPB plasma was evaluated using a Transwell culture system， and the levels of surface CXCR4 protein， phosphorylated CXCR4 and CXCR4 mRNA in the NLC were also evaluated by flow cytometry， Western blot and RT-qPCR， respectively. The NLC chemotaxis index to the plasma in CPB group was increased significantly， which were 3.89±0.77 vs 7.68±1.55 at T1 and T2， respectively. And this increased chemotaxis could be inhibited by CXCR4 specific antagonist AMD3100. Simultaneously， as well as the levels of surface CXCR4 protein and phosphorylated CXCR4 of the NLC were increased significantly in the CPB group but not in N-CPB group. However， there were no significant differences between the N-CPB and CPB group in CXCR4 mRNA level. Cardiopulmonary bypass children derived plasma can activate the CXCR4 signal pathway in neutrophil-like cells in vitro， and its mechanism may relate to the increased surface protein and its phosphorylation levels， not relate to the mRNA level. These mechanisms might be involved in the neutrophils infiltration into pulmonary and other extravascular tissues during CPB.

CSTR: 32200.14.cjcb.2018.03.0006