A Three-Dimensional Microporous Decalcified Bone Matrix Combined with Bone Marrow Mesenchymal Stem Cells Enhances Bone Regeneration in Critical-Sized Calvarial Defect of Nude Mouse

The clinical repair of bone defects is hindered by limitations in donor material and complications arising from autologous bone grafting. Consequently, the development of efficient bone regeneration materials is of great clinical importance. The present study investigated a three-dimensional microporous demineralized bone matrix (DBM) combined with bone marrow mesenchymal stem cells (BMSCs) to enhance the outcomes of bone defect repair. The DBM has been developed to enhance the collagen preparation process, with the aim of retaining the collagen fiber network of the natural bone matrix and forming a three-dimensional microporous structure with good mechanical property. In vitro experiments demonstrated that the biocompatibility of DBM was superior to that of traditional cancellous and cortical bone materials, and they promoted cell adhesion, proliferation, and osteogenic differentiation as well as osteogenesis-related genes. In vivo experimentation was conducted to verify the efficacy of the treatment on a critical-sized cranial bone defect in nude mice. Micro-CT and histological analysis showed more formation of bone at 4 weeks and 8 weeks postsurgery. The DBM with optimized pore structure, degradation rate, and bioactivity enhanced the efficiency of bone defect repair by synergizing the osteogenic activity of BMSCs. The DBM with a porous and cross-linked structure could provide BMSCs with more internal surface area for attachment space to promote cell adhesion and growth and create advantages for the bone formation. Moreover, the DBM contains multifarious osteoinductive growth factors such as transforming growth factor-β (TGF-β), fibroblast growth factors (FGFs), bone morphogenetic proteins (BMPs) and insulin growth factors (IGFs), which can enhance osteogenic differentiation of BMSCs. This study may provide an innovative strategy for bone regeneration and bone defect repair.