MiR‐140‐5p promotes osteogenic differentiation of mouse embryonic bone marrow mesenchymal stem cells and post‐fracture healing of mice

MiR‐140‐5p is high expressed in normal fracture healing, but its specific role and mechanism in tissue‐to‐bone healing are rarely reported. Therefore, this study investigated the effects of miR‐140‐5p on tissue‐to‐bone healing. Clone formation experiment, flow cytometry, Alizarin Red S Staining and Oil Red O Staining were performed to investigate the biological characteristics of mouse embryonic bone marrow mesenchymal stem cells C3H10T1/2. MiR‐140‐5p mimic was transfected into osteogenic medium (OS)‐treated C3H10T1/2 cells to investigate the effects of miR‐140‐5p on osteogenic differentiation. MiR‐140‐5p transgenic mouse model and the transgenic fracture model were established, and the effects of miR‐140‐5p on osteogenic differentiation, bone mineral density (BMD) and bone mass of bone tissues were detected by haematoxylin and eosin staining and computed tomography scan. The expressions of osteocalcin, differentiation‐related genes (Runx2, ALP, Spp1 and Bglap3) and miR‐140‐5p were determined by quantitative real‐time polymerase chain reaction. C3H10T1/2 cells showed the abilities of forming cloned differentiation of osteogenesis, fat cells, and its phenotypes including CD44, CD90.1 and Sca‐1 but excluding CD45 haematopoietic stem cell marker. Overexpression of miR‐140‐5p promoted the expressions of differentiation‐related genes and calcium deposition of OS‐treated C3H10T1/2 cells. MiR‐140‐5p increased the expression of osteocalcin, BMD and bone mass and promoted bone healing of miR‐140‐5p‐transgenic mice with fracture. MiR‐140‐5p promoted osteogenic differentiation of mouse embryonic bone marrow mesenchymal stem cells and post‐fracture healing in mice. SIGNIFICANCE OF THE STUDY: C3H10T1/2 cells showed the abilities of forming cloned differentiation of osteogenesis, fat cells and its phenotypes including CD44, CD90.1 and Sca‐1 but excluding CD45 haematopoietic stem cell marker. Overexpression of miR‐140‐5p promoted the expressions of differentiation‐related genes and calcium deposition of osteogenic medium‐treated C3H10T1/2 cells. MiR‐140‐5p increased the expression of osteocalcin and bone mineral density and bone mass and promoted bone healing of miR‐140‐5p‐transgenic mice with fracture. Our results showed that miR‐140‐5p promoted osteogenic differentiation of mouse embryonic bone marrow mesenchymal stem cells and post‐fracture healing in mice, which may be a therapeutic target for treating fractures and promoting bone healing.