Acceleration of bone repairation by BMSCs overexpressing NGF combined with NSA and allograft bone scaffolds

Background Repairation of bone defects remains a major clinical problem. Constructing bone tissue engineering containing growth factors, stem cells, and material scaffolds to repair bone defects has recently become a hot research topic. Nerve growth factor (NGF) can promote osteogenesis of bone marrow mesenchymal stem cells (BMSCs), but the low survival rate of the BMSCs during transplantation remains an unresolved issue. In this study, we investigated the therapeutic effect of BMSCs overexpression of NGF on bone defect by inhibiting pyroptosis. Methods The relationship between the low survival rate and pyroptosis of BMSCs overexpressing NGF in localized inflammation of fractures was explored by detecting pyroptosis protein levels. Then, the NGF ⁺ /BMSCs-NSA-Sca bone tissue engineering was constructed by seeding BMSCs overexpressing NGF on the allograft bone scaffold and adding the pyroptosis inhibitor necrosulfonamide(NSA). The femoral condylar defect model in the Sprague-Dawley (SD) rat was studied by micro-CT, histological, WB and PCR analyses in vitro and in vivo to evaluate the regenerative effect of bone repair. Results The pyroptosis that occurs in BMSCs overexpressing NGF is associated with the nerve growth factor receptor (P75NTR) during osteogenic differentiation. Furthermore, NSA can block pyroptosis in BMSCs overexpression NGF. Notably, the analyses using the critical-size femoral condylar defect model indicated that the NGF ⁺ /BMSCs-NSA-Sca group inhibited pyroptosis significantly and had higher osteogenesis in defects. Conclusion NGF ⁺ /BMSCs-NSA had strong osteogenic properties in repairing bone defects. Moreover, NGF ⁺ /BMSCs-NSA-Sca mixture developed in this study opens new horizons for developing novel tissue engineering constructs.