Abstract
Bone morphogenetic protein 2 (BMP-2) and transforming growth factor β (TGF-β) isoforms are important in advancing bone regeneration. The aim of the present study was to investigate the positive and reciprocal effect of TGF‑β3, one of the three TGF‑β isoforms, on BMP‑2 in promoting osteogenic differentiation. Exogenous BMP‑2 and TGF‑β3 genes were separately, and in combination, overexpressed in rabbit bone marrow‑derived mesenchymal stem cells (rBMSCs). Expression levels of BMP‑2 and TGF‑β3 were evaluated using reverse‑transcription‑polymerase chain reaction (RT‑PCR) and Western blotting assays. Furthermore, the osteogenic differentiation capacities of BMSCs were assessed by measuring Alizarin Red S staining, an alkaline phosphatase activity assay, and quantification of the osteogenic‑specific genes, Runt‑related transcription factor 2 (Runx2) and Osterix (Osx). Using lentiviral‑mediated transfection, robust co‑transfection efficiency of >90% was achieved. RT‑PCR and immunoblotting results indicated a marked elevated expression of BMP‑2 and TGF‑β3 in rBMSCs undergoing co‑transfection, compared with transfection with BMP‑2 or TGF‑β3 alone, indicating that BMP‑2 and TGF‑β3 are synergistically expressed in rBMSCs. Furthermore, enhanced osteogenic differentiation was observed in rBMSCs co‑transfected with BMP‑2/TGF‑β3. The present study successfully delivered BMP‑2 together with TGF‑β3 into rBMSCs with high efficiency for the first time. Furthermore, TGF‑β3 overexpression was demonstrated to enhance the osteogenic efficacy of BMP‑2 in rBMSCs, and vice versa. This provides a potential clinical therapeutic approach for regenerating the function of osseous tissue, and may present a promising strategy for bone defect healing.