Abstract:Aim To investigate the effects of bradykinin (BK) of different concentrations on the survival, migration and apoptosis of human umbilical cord blood derived endothelial progenitor cells (hEPC) in vitro. Methods Total mononuclear cells (MNC) were isolated from human cord blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin- coated culture dished. After 7 days cultured, attached cells were isolated and assessed by immunofluorescence. Differentiating EPC were characterized as adherent cells double positive for both DiI-acLDL and FITC-UEA-1. Flow cytometry were used to further confirm EPC. EPC were treaed with BK of different concentrations (1, 10, 100 nmol/L), or HOE140 (BK B2 receptor inhibitor) plus BK (10 nmol/L) for 16 h. The effects of BK on EPC’ survival, migration and apoptosis were assayed with MTT assay, Transwell chamber assay, flow cytometry assay using Annexin V-FITC/PI assay and Hoechst 33342 staining, respectively. Results BK at 1 and 10 nmol/L significantly improved the ability in the survival, migration and anti-apoptosis of hEPC (P< 0.05), which was not at the concentration of 100 nmol/L (P> 0.05). And the effects of BK on these functions of hEPCs could be blocked by HOE140 (P< 0.05). Conclusion The present study established that BK in a certain concentration range could improve hEPC’ survival, migration and anti- apoptosis capability, and this effect might be mediated by BK-B2 receptor.