ABSTRACT
Neural crest cells possess characteristics of stem cells including plasticity and ability to differentiate into various cell types. HNK1 and Sox10 are markers of neural crest cell progenitors that have been demonstrated in osteoblasts during osteogenesis of the maxilla and mandible. We investigated the presence of Sox10 and HNK1 during regeneration of mandibular bone defects. Defects were created in mandibles of rats. Samples of these defects were collected at 7, 14 and 28 days post-surgery; bone regeneration was observed during this period. Immunohistochemical analysis revealed expression of HNK1 and Sox10 in osteoblasts, osteocytes and osteogenic cells, whereas osteoclasts were unstained. HNK1 expression was increased in osteoblasts and osteocytes over time and SOX10 expression was found in osteoblasts and osteogenic cells at 7, 14 and 28 days post-surgery. HNK1 and Sox10 are present in osteoblasts, osteocytes and osteogenic cells during mandible bone regeneration.
Subject(s)
Bone Regeneration/physiology , CD57 Antigens/metabolism , SOXE Transcription Factors/metabolism , Animals , Biomarkers/metabolism , Gene Expression Regulation , Male , Mandible , Osteoblasts/metabolism , Osteocytes/metabolism , Rats , Rats, Wistar , SOXE Transcription Factors/geneticsABSTRACT
BACKGROUND AND OBJECTIVE: The periodontal ligament is a specialized connective tissue, derived from dental follicle and originated from neural crest cells. Recently it has been suggested, based on animal models, that periodontal ligament could be a niche for neural crest stem cells. However, there is still little knowledge on this subject. The identification of neural crest adult stem cells has received much attention based on its potential in tissue regeneration. The objective of the present work was to verify the human periodontal ligament as a niche for neural crest stem cells. MATERIAL AND METHODS: Cells from human periodontal ligament were isolated from 10 teeth of seven individuals (periodontal ligament pool group) and also from four teeth of one individual (periodontal ligament single group), after enzymatic digestion. The cells were cultured in specific inductive medium. Analyses of protein and gene expression were performed through immunocytochemistry and reverse transcription-polymerase chain reaction techniques, respectively. RESULTS: Mesodermal phenotypes (adipogeneic, osteogenic and myofibroblastic) were identified after culture in inductive medium. Immunocytochemistry analyses showed the presence of the nestin marker of neural stem cells and also markers of undifferentiated neural crest cells (HNK1, p75). When cultured in inductive medium that allowed neural differentiation, the cells showed markers for beta-tubulin III, neurofilament M, peripherin, microtubule-associated protein 2 and protein zero. The results were similar between the two study groups (the periodontal ligament pool group and the periodontal ligament single group). CONCLUSION: This research provides evidence that human periodontal ligament, in addition to its mesodermal derivatives, produces neural crest-like cells. Such features suggest a recapitulation of their embryonic state. The human periodontal ligament revealed itself as a viable alternative source for possible primitive precursors to be used in stem-cell therapies.
