Combinatorial Effect of Stem Cells Derived from Mandible and Recombinant Human Bone Morphogenetic Protein-2

Bone morphogenetic protein-2 (BMP-2) is known to be an active inducer of osteoblast differentiation and mesenchymal stem cells (MSCs) have been applied as an alternative strategy for bone regeneration. The aim of this study was to evaluate the combined effects of easily accessible MSCs easily harvested in the outpatient department under local anesthesia and BMP-2 on the bone regeneration using rabbit calvarial defect model. The defects measuring 6 mm in diameter were prepared in the cavarium of New Zealand white rabbits. The MSCs were isolated from the mandible during the tooth extraction. The defects were grafted with 1) beta-tricalcium phosphate/hydroxyapatite (beta-TCP/HA) only, 2) 1x10(6) MSCs loaded with beta-TCP/HA, 3) beta-TCP/HA containing recombinant human BMP-2, and 4) 1x10(6) MSCs loaded with beta-TCP/HA containing rhBMP-2. Groups without any graft material served as negative control. At 4 weeks, highest bone formation was achieved in beta-TCP/HA+rhBMP-2+MSC group and there was statistically significant increase of bone fill in the beta-TCP/HA+rhBMP-2+MSC group when compared with the negative control group (p < 0.05). The quantity of new bone at 6 weeks was greater than that observed at 4 weeks in each group and alkaline phosphatase staining was evident throughout the images in groups implanted with graft material. This study showed that combining easily accessible MSCs and commercially available BMP-2 resulted in significant increase of bone regeneration. Within the limits of this study, it could suggest that the MSCs from mandible may be combined with BMP-2 to enhance bone regeneration in early healing period.