Abstract： Objective To study the different expression of 4 microRNA (miRNA,miR) during the osteogenesis differentiation of bone marrow mesenchymal stem cell (BMSC) cultured in high-fat or normal environment and to explore the relationship of these miRNAs with disheveled 2 during osteogenesis differentiation.Methods BMSC were cultured with 2 ml normal osteogenic induction (control group) and high-fat osteogenic induction (high-fat group) respectively.On the 3rd,5th,7th,14th,21st day,quantitative real-time PCR (qPCR) was used to analyze expression levels of four miRNAs (miR-21-5p,miR-29c-3p,miR-138-Sp and miR-351-5p),mRNA of disheveled 2,osteogenic related factors such as alkaline phosphatase (ALP),Runt-related transcription gene 2 (Runx2).And the protein was detected by Western blotting.After BMSC were transfected by 50 μl 50 nmol/L miRNA mimics/inhibitors/negative controls respectively,BMSC were put on osteogenic induction,on the 1st,3rd,5th,7th day,ALP activity was detected.On the 7th day,ALP staining was to observe the degree of osteogenesis differentiation,and Western blotting was adopted to analyze the expression of dishevelled 2 and other osteogenic related factors,while qPCR was used to analyze the expression of disheveled 2 mRNA.After 293T cells were co-transfected with disheveled 2 wild-type/mutant firefly luciferase reporter plasmid with either negative control (NC) or a mimic of these four miRNAs respectively for 48 h,luciferase activities were measured.Results On the 21th day,the expressions of miR-21-5p,miR-29c-3p,miR-138-5p and miR-351-5p in high-fat groups were higher by 20％,60％,340％ and 4 420％ respectively than those in control groups (P＜0.05).The expression of ALP and Runx2 in BMSC decreased after BMSC transfected miR-21-5p and miR-29c-3p mimics,while increased after transfected miR-21-5p and miR-29c-3p inhibitors.The expression of disheveled 2 decreased by 35％ after transfected by miR-29c-3p mimic,while it increased by 269％ after transfected by miR-29c-3p inhibitor (P＜0.05).Transfection of the miR-29c-3p mimics significantly decreased the luciferase activity of wild-type 3'-UTR compared with NC control (P＜0.05).There were no statistical significances among other groups.Conclusions miRNAs had better expression during osteogenesis differentiation of BMSC in high-fat environment;miR-29c-3p could negatively regulate the osteogenesis differentiation of BMSC by targets on dishevelled 2.