[CONDITIONED MEDIUM OF BONE MARROW MESENCHYMAL STEM CELLS ALLEVIATE INHIBITING EFFECT OF DEXAMETHASONE ON OSTEOGENETIC CAPABILITY OF OSTEOBLAST].

OBJECTIVE: To explore the paracrine effect of bone marrow mesenchymal stem cells (BMSCs) on dexamethasone-induced inhibition of osteoblast function in vitro. METHODS: The serum free conditioned medium of mouse BMSCs cultured for 24 hours was prepared for spare use. The 3rd passage of MC3T3-E1 cells were divided into 4 groups: the control group (group A), dexamethasone group (group B), dexamethasone+BMSCs conditioned medium (1:1) group (group C), and BMSCs conditioned medium group (group D). After 24 hours of culture, the alkaline phosphatase (ALP) content was determined; the protein expressions of RUNX2 and Osteocalcin were detected by Western blot; and the gene expressions of collagen type I-α 1 (COL1A1), RUNX2, ALP, and Osteocalcin were detected by real-time fluorescence quantitative PCR (RT-qPCR); alizarin red staining was used to observe calcium nodules formation at 21 days. RESULTS: > 0.05). The cells of group A all died at 6 days after culture; at 21 days, the calcium no dule staining was positive by alizarin red in groups B, C and D, and the degree of the staining gradually increased from groups B to D. CONCLUSIONS: BMSCs conditioned medium can alleviate the inhibitory effect of dexamethasone on osteoblasts function.