Objective      To investigate the synergistic effect of vascular endothelial growth factor (VEGF) and transforming growth factor-β1 (TGF-β1) on osteogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (BMSCs) and its possible mechanisms.       Methods      Cells were divided into 4 groups

i.e. control

adeno-associated virus (AAV)-VEGF group

AAV-TGF-β1 group and VEGF+TGF-β1 group. The bone marrow was extracted from rabbit femoral trochanter by puncturing and BMSCs were isolated. Primary-cultured BMSCs were transfected with AAV-VEGF and AAV-TGF-β1 adenoviral vectors

respectively. The protein levels of VEGF and TGF-β1 were measured by Western blotting. Cell apoptosis was detected by flow cytometry and cell proliferation was measured by CCK-8 assay. The expression of nucleus pulposus cell marker proteins (SOX-9

Collagen Ⅱ and Aggrecan) and P38MAPK signaling pathway-related proteins (P38

MAPKAPK and HSP27) were measured by Western blotting. BMSCs were pretreated with SB203580

a specific P38MAPK inhibitor. The effects of VEGF and TGF-β1 on the proliferation

apoptosis

differentiation of treated BMSCs and associated protein expressions were measured.       Results      VEGF or TGF-β1 inhibited BMSCs apoptosis

increased BMSCs proliferation and promoted their differentiation to nucleus pulposus-like cells through P38MAPK signaling pathway. Moreover

these effects were reinforced by synergistic action of VEGF and TGF-β1. Inhibiting P38MAPK pathway reversed the accelerating effect of VEGF and TGF-β1 on the proliferation and differentiation of BMSCs.       Conclusion      VEGF and TGF-β1 synergistically enhance BMSCs proliferation and differentiation

elevate the expression of extracellular matrix including collagen and proteoglycan

and thus promote the repair and regeneration of degenerative intervertebral discs.