Objective To study the role of p38 pathway in the regulation of vascular endothelial growth factor (VEGF) expression by recombinant human bone morphogenetic protein-2 (rhBMP-2) in human adipose-derived stem cells (hADSCs).Methods hADSCs were isolated from adult human adipose tissue and cultured until passage 3.Then the cells were induced with rhBMP-2 at final concentrations of 0 ng/mL,50 ng/mL,100 ng/mL and 200 ng/mL respectively.Samples were collected after incubation for 24 hours.Before using 100 ng/mL rhBMP-2,the cells were first inhibited by p38 inhibitor sb203580 at concentrations of 0 μmol/mL,5 μ mol/mL and 15 μmol/mL for 30 minutes.Samples were collected after incubation for 24 hours.RT-PCR and Western-blot were used to detect the changes in expressions of VEGF and p38 and their relevance was compared.Results The expression of VEGF was closely related to the phosphorylation of p38.In 0 ng /mL group,the expression of VEGF and activation level of p-p38 were low.In 100 ng/mL group,the expression of VEGF and the activation level of p-p38 were significantly higher than in other groups (P < O.05).In 200 ng/mL group,rhBMP-2 inhibited the VEGF expression and the activation level of p-p38 was also inhibited.p38 inhibitor sb203580 inhibited the VEGF expression in a concentration dependent manner,with the VEGF barely expressed in 15 μmol/mL group.Conclusion p38 signaling pathways is involved in the regulation of VEGF expression by rhBMP-2 in hADSCs. Key words: Bone morphogenetic proteins; Vascular endothelial growth factor; Mesenchymal stem cells