Histological Study of Cultured Dental Pulp Cells Transplanted in Periodontal Bone Defects

Abstract

Pluripotent mesenchymal stem cells are essential for regeneration by tissue engineering. These stem cells, which are derived from periodontal ligament, bone marrow and dental pulp, are used in the dental field. We evaluated the properties of adult dental pulp cells collected from teeth extracted for orthodontic reasons and cultured the cells with b-FGF (basic-fibroblast growth factor) to promote the growth of mesenchymal stem cells. ALP activity and gene expression of osteopontin (OPN), osteocalcin (OC), bone sialoprotein (BSP) and dentin sialophosphoprotein (DSPP) were determined. The results showed that ALP activity increased and gene expression of the bone molecular markers, OPN, OC and BSP, and DSPP, a molecular marker of dentin, increased in the presence of b-FGE When surface antigens of dental pulp stem cells cultured in the presence of b-FGF were examined, the hematopoietic stem cell markers CD34 and CD45 were negative, and the mesenchymal stem cell markers CD44 and CD90 were positive. The cultured dental pulp stem cells were then transplanted into artificially created periodontal bone defects in nude rats using collagen gel as a carrier. Connective tissue attachment and bone regeneration were not found in the control defects where only collagen gel was transplanted, but connective tissue attachment was observed in the experimental defects in which collagen gel and cells were transplanted. In the present study, no regeneration of alveolar bone was observed, but periodontal tissue regeneration using dental pulp stem cells appeared to be possible.