| Summary: | 碩士 === 國防醫學院 === 生物及解剖學研究所 === 102 === Bone regeneration usually needs stem cells which play a role in bone healing of osteogenesis, osteoinduction, osteoconduction and osteopromotion. Biologically, in bone healing stage, stem cells can be differentiated into components of fracture callus to help bone formation. In the last decades, there are growing studies about stem cells cultured with type I collagen. Results showed high alkaline phosphatase activity, collagen synthesis, and mineralized tissues formed. In our study, the human dental pulp stem cells from supernumerary teeth (defined DPSCs) established in our laboratory were cultured on well plate and evaluated the capacity of type I collagen on osteo-differentiation. To confirm the stemness and osteo-differentiation of DPSCs, we use immunofluorescence stain and chemical stain to quantify. The non-differentiated DPSCs expressed markers of OCT-4, NANOG, REX-1, BMP-4 and Nestin. After induction of osteo-differentiation, the early mesoderm marker, BMP4 was continuously expressed. The osteoblast marker, osteocalcin was expressed in both groups at one and two weeks after osteo-differentiation. However the chondrogenesis marker SOX9 expressed in osteo-differentiated DPSCs for two weeks without type I collagen induction. The data of Alizarin Red stain and von Kossa stain also showed positive expression in both one and two weeks with type I collagen induction. Furthermore, we grafted DPSCs with type I collagen in the rat cranial bone defects to evaluate bone repair and regeneration. Postoperative eight weeks, the animals were sacrificed and measured the cranial bone recovery by radiography. The bone repair of pulp stem cells with type I collagen group is better than other groups. The evidences of this study indicated that type I collagen is not only an improvement factor for the osteo-differentiation but also an important matrix for DPSCs based bone repair therapy.
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