Effects of endothelial progenitor cells on acute lung rejection after lung transplantation

Objective To estimate the effects of endothelial progenitor cell(EPC) on acute rejection after lung transplantation. Methods Twenty-four Wistar rats were randomly divided into three groups (n=8): a sham operation group (opening chest alone, group S), a control group[intravenous injection of phosphate buffer saline (PBS) after orthopedic left lung transplantation, group C] and an endothelial progenitor cell group(intravenous injection of EPC+PBS after orthopedic left lung transplantation, group EPC). The donor was SD rat. Total sixteen SD rats were used. The blood of three groups of recipient rats was collected from femoral artery on Day 7 after operation. Then the oxygenation index (PaO2/FiO2) was measured by blood gas analysis while the concentrations of serum inflammatory factor intercellular cell adhesion molecule-1 (ICAM-1) and lymphocytefunctionassociatedantigen-1 (LFA-1) were measured by ELISA. The lungs of sacrificed rats were taken. Then, partial lung tissues were used to measure the dry and wet tissues specific gravity. other part of lung tissues were used to measure concentrations of inflammatory factors interferon-γ(IFN-γ) and interleukin(IL)-2, IL-10 by enzyme linked immunosorbent assay (ELISA) and to evaluate reject reaction by hematoxylin-eosin (H-E) staining. Results Compared with the group C, PaO2/FiO2 was increased whereas the wet/dry weight ratio and protein concentrations were decreased in group EPC(P<0.05). The levels of serum ICAM-1, LFA, IFN-γ and IL-2 in transplanted lung tissues were down-regulated, but the level of IL-10 was up-regulated in group EPC(P<0.05). The reject reaction score of group C (4.3±1.1) and group EPC(2.4±0.8) were higher than the score in group S(0). Conclusions EPC is able to relieve lung acute reject reaction after lung transplantation. Key words: Lung transplantation; Acute rejection; Endothelial progenitor cell