Healing Pattern in Calvarial Bone Defects Following Bone Regeneration in Rats Guided by Chitosan Scaffold and Adipose Tissue-Derived Mesenchymal Stem Cells

Cell-based tissue engineering using scaffolds provides a promising option for the repair of bone tissue damage caused by trauma or aging-related degeneration such as osteoporosis. In this study, a porous 3D scaffold was used to support the differentiation process of rat adipose -derived stem cells (ADSCs) into osteoblasts in vitro. The scaffold was made with chitosan, gelatin and chondroitin. In addition, the scaffold was crosslinked by glutaraldehyide. The osteogenic differentiation of ADSCs was improved in 3D culture as shown by the cell viability assay (MTT) and analyses of, alkaline phosphatase activity (ALP), and collagen production during three weeks of culturing. During the 2nd and 3rd weeks of culturing, bone markers, such as osteopontin and osteocalcin, were detected by the PCR analysis. In vivo biocompatibility was evaluated subcutaneously in rats. A mild inflammatory response was observed during the 5 weeks. Reduction of the matrix fibers by reabsorptive cells and formation of new blood vessels were observed during this period. However, no inflammation was observed. Five weeks after the implants were placed in the calvaria -defects, a small amount of bone repair was observed. In addition, immunohistochemistry revealed the presence of EGFPs ADSCs in the newly formed extracellular matrix. These findings indicated that the chitosan-gelatin-chondroitin 3D structure enhances cellular proliferation, which may be useful in the development of biomaterials for the stimulation of adult stem cells in bone tissue engineering.