Porcine brain extract promotes osteogenic differentiation of bone marrow derived mesenchymal stem cells and bone consolidation in a rat distraction osteogenesis model

Distraction osteogenesis (DO) is the gold standard to treat large bone defects, but long consolidation period is a major limitation. Innovative efforts to promote osteogenesis are needed. Porcine brain extract (PBE) was reported to enhance the proliferation and differentiation of multiple primary cells. In this study, we aimed to develop a method for collecting PBE and investigate its effects on osteogenic differentiation of rat bone marrow derived mesenchymal stem cells (rBMSCs) and bone consolidation in a rat DO model. The PBE was collected from neonatal brain tissues of porcine fetus and was used to treat rBMSCs. Following PBE treatment (700 ng/ml), osteogenic differentiation was assessed. Further, we locally injected PBE (7 μg/ml, 100μl) or PBS (100μl) into the gap in a Sprague-Dawley (SD) male rat DO model every three days till termination. X-rays, micro-computed tomography, mechanical testing, histology and immunohischemistry examinations were used to exam the quality of the regenerates. The alkaline phosphatase, calcium deposits, and steogenic markers in the PBE treated rBMSCs were significantly increased. In the rat model, new bone properties of bone volume/total tissue volume and mechanical strength were higher in the PBE treated group. Histological analysis also confirmed more mineralized bone after PBE treatment. The current study reports a standard protocol for PBE collection and demonstrated its positive effects on osteogenic differentiation and bone consolidation in DO. Since the PBE is readily available and very cost effective, PBE may be a potential new bio-source to promote bone formation in patients undergo DO treatment.