RESUMEN
BACKGROUND:Tetracycline hydrochloride not only promotes the proliferation of bone marrow mesenchymal stem cells (BMSCs),but also has a strong bone activity.Studies on the osteogenic differentiation of BMSCs induced by tetracycline hydrochloride will provide a new cell source for bone tissue engineering.OBJECTIVE:To observe the induction and differentiation activity of BMSCs into osteoblasts cultured by tetracycline hydrochloride in vitro.METHODS:BMSCs were separated and expanded by whole bone marrow adherent method and identified by cell morphology and BMSCs cell markers CD34,CD45,CD90,CD29.Passage 3 BMSCs were collected and cultured with tetracycline hydrochloride (experimental group) or cultured in L-DMEM containing 10％ fetal bovine serum (control group).Osteogenic induction and differentiation activity of BMSCs cultured by tetracycline hydrochloride were detected by alkaline phosphatase activity detection,collagen I and osteocalcin immunohistochemistry staining,alizarin red staining of mineralized calcium nodules,and detection of collagen I and osteocalcin gene expression by RT-PCR.RESULTS AND CONCLUSION:Tetracycline hydrochloride continuously promoted alkaline phosphatase activity in the BMSCs,significantly different from that in the control group.After 21 days of culture,positive expression of collagen I and osteocalcin proteins,red calcium nodules shown by alizarin red staining,and mRNA expression of collagen I and osteocalcin were observed in the experimental group,while the negative expression was found in the control group.In conclusion,tetracycline hydrochloride has a significant role to promote the osteogenic differentiation of BMSCs.