Evaluation of the effects of the combination of autologous mesenchymal stem cells and platelet-rich plasma on structural bone allograft healing.

In this study, we evaluated the efficacy of the combination of autologous mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) for enhancing structural allogenic bone graft healing in rabbits. For these experiments segmental bone defects (1.5-2 cm) were generated on femoral diaphysis of New Zealand white rabbits and reconstructed via structural allogenic bone grafting and additional intramedullary nail fixation. The structural allografts were subsequently wrapped with Gelfoam containing autologous MSCs and PRP, or PRP alone (control). Grafted periosteal tissues were harvested at 4, 8, and 12 weeks post-implantation and subjected to plain radiographic and, histological, as well as real-time quantitative reverse transcription-PCR analysis of bone morphogenic protein (BMP)-2, BMP-4, BMP-7, receptor activator of nuclear factor-kappa B ligand (RANKL), and vascular endothelial growth factor (VEGF) expression. Compared to those in the control group, the animals in the experimental group exhibited significantly higher Taira radiographic scores at 4 and 12 weeks after surgery, as well as callus formation. Likewise, these animals exhibited increases in BMP-4 production at 4 weeks, RANKL production at 4 and 12 weeks, and BMP-2, BMP-7, and VEGF production at 4, 8, and 12 weeks. Together, these data suggest that the administration of autologous MSCs and PRP resulted in enhanced healing of structural allogenic bone grafts compared to PRP alone. As such, this combination might comprise an ideal therapy for improving the clinical outcomes of structural allografts.