ABSTRACT
OBJECTIVE:To investigate the paracrine effects of bone marrow mesenchymal stem cells on osteoblast biological function. METHODS:Bone marrow mesenchymal stem cells were isolated using standard Ficol-Paquedensity gradient centrifugation. Mesenchymal stem cellconditioned medium was prepared to cultivate osteoblasts, MG63. Proliferation of MG63 cells was analyzed by cellcounting kit-8. Migration of MG63 cells was analyzed by cellscratch method. Alkaline phosphatase activity of MG63 cells was analyzed by microplate test kit. Real-time PCR was performed to evaluate osteoblast differentiation markers, alkaline phosphatase, col agen type I and osteocalcin. Alizarin red staining was performed to evaluate osteoblast mineralization. RESULTS AND CONCLUSION:The cells were strongly positive for CD44, CD73 and CD90, but negative for CD34. MG63 cells cultured in the conditioned medium showed better proliferation and migration than those cultured in the Dulbecco’s modified Eagle’s medium. The activity and mRNA expression of alkaline phosphatase were much higher after induction of 4, 7 days (P<0.01). There was no significant difference in expression of col agen type I and osteocalcin after induction of 4 days, but they were significantly higher than those in the control group after induction of 7 days (P<0.05). Alizarin red staining showed that the number of calcium nodules was increased and the mineral apposition was enhanced after induction of 21 days with the conditioned medium. These findings suggest that the paracrine substance of bone marrow mesenchymal stem cells can significantly promote osteoblast proliferation, migration, differentiation and mineralization.