〔Abstract〕 Objective To investigate the role and mechanism of long non-coding RNA(lncRNA) H19 in osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs) and bone regeneration in mice with foot fracture.Methods BMSCs were divided into microrNA-149-5 p(miR-149-5 p)-mimic negative control(miR-mimicNC) group and miR-149-5p-mimic(miR-mimic) group and transfected with IncRNA H19-wt and IncRNA H19,respectively.Mut recombinant plasmid,or bone morphogenetic protein 2(BMP2) 3'UTR-wt and BMP2 3' UTRmut recombinant plasmid were transfected,respectively.Dual-luciferase reporter gene assay was used to detect the luciferase activity of each group.To study the regulatory effect and mechanism of IncRNA H19 on osteogenic differentiation in vitro,BMSCs were divided into control group and osteogenic induction group(osteogenic group).After osteogenic induction,BMSCs were transfected with corresponding plasmids and divided into osteogenic+si-NC group,osteogenic+si-H19 group,osteogenic+si-H19+miR-inhibitor-NC group,osteogenic+si-H19+miR-inhibitor group,osteogenic+si-H19+pcDNA-NC group,and osteogenic group si-H19+pcDNA-BMP2 group.Osteogenic differentiation was evaluated by alkaline phosphatase(ALP) activity assay and alizarin red staining.A mouse foot fracture model was established,and 36 mice were randomly divided into sham operation group,model group,model+pcD-null group,and model+pcD-H19 group,with 9 mice in each group.Osteogenic differentiation was assessed by ALP activity assay.Real-time fluorescent quantitative PCR(qPCR) was used to detect the expression of IncRNA H19,miR-149-5p,and BMP2.Western blot was used to detect the expression of BMP2,OCN,OSX,RUNX2,and OPN.Results In cells transfected with IncRNA H19-wt,the luciferase activity in miR-mimic group was lower than that in miR-mimic-NC group(P