Reconstruction of rat calvarial defects with human mesenchymal stem cells and osteoblast-like cells in poly-lactic-co-glycolic acid scaffolds.

Human mesenchymal stem cells (hMSCs) can be used for xenogenic transplantation due to their low immunogenicity, high proliferation rate, and multi-differentiation potentials. Therefore, hMSCs are an ideal seeding source for tissue engineering. The present study evaluates the reconstruction effects of hMSCs and osteoblast-like cells differentiated from hMSCs in poly-lactic-co-glycolic acid (PLGA) scaffolds on the calvarial defect of rats. Two bilateral full-thickness defects (5mm in diameter) were created in the calvarium of nonimmunosuppressed Sprague-Dawley rats. The defects were filled by PLGA scaffolds with hMSCs (hMSC Construct) or with osteoblast-like cells differentiated from hMSCs (Osteoblast Construct). The defects without any graft (Blank Defect) or filled with PLGA scaffold without any cells (Blank Scaffold) were used as controls. Evaluation was performed using macroscopic view, histology and immunohistochemical analysis respectively at 10 and 20 weeks after transplantation. In addition, fluorescent carbocyanine CM-Dil was used to track the implanted cells in vivo during transplantation. The results showed that while both hMSC Construct and Osteoblast Construct led to an effective reconstruction of critical-size calvarial defects, the bone reconstruction potential of hMSC Construct was superior to that of Osteoblast Construct in non-autogenous applications. Our findings verify the feasibility of the use of xenogenic MSCs for tissue engineering and demonstrate that undifferentiated hMSCs are more suitable for bone reconstruction in xenotransplantation models.