MgO-enhanced β-TCP promotes osteogenesis in both in vitro and in vivo rat models

Allogeneic bone grafts are used to treat bone defects in orthopedic surgery, but the osteogenic potential of artificial bones remains a challenge. In this study, we developed a beta-tricalcium phosphate (beta-TCP) formulation containing MgO, ZnO, SrO, and SiO2 and compared its bone-forming ability with that of beta-TCP without biological elements. We prepared beta-TCP discs with 60% porosity containing 1.0 wt% of these biological elements. beta-TCP scaffolds were loaded with bone marrow-derived mesenchymal stem cells (BMSC) from 7-week-old male rats and cultured for 2 weeks. ALP activity and mRNA expression of osteogenic markers were evaluated. In addition, scaffolds were implanted subcutaneously in rats and analyzed after 7 weeks. In vitro, the MgO group showed lower Ca concentrations and higher osteogenic marker expression compared to controls. In vivo, the MgO group showed higher ALP activity compared to controls, and RT-qPCR analysis showed significant expression of BMP2 and VEGF. Histopathology, fluorescent immunostaining, and micro-CT also showed relatively better bone formation in the MgO group. beta-TCP with MgO may enhance bone morphology in vitro and in vivo and improve the prognosis of patients with substantial and refractory bone defects.