The Differentiation Of Periodontal Ligament Stem Cells Into Cementoblast-like Cells By The Promotion Of Apical Tooth Germ Cell-conditioned Medium

Cementum is an important hard connective tissue that links the periodontium and thesurface of tooth root tightly. When tooth is exposed to inflammatory environment orabnormal stimulus, cementum might be destroyed or even irreversible tooth rootresorpted. However, there are limited cementoblasts sources after tooth developmentcompletion. Periodontal ligament stem cells (PDLSCs) which have the characters ofself-renewing and multipotential differentation are the ideal cell-sources forcementum regeneration. Researches have demonstrated that microRNAs play animportant role in regulating the self-renewing and multipotential differentiationcharacters of stem cells. In this research, we tried to use apical tooth germcell-conditioned medium (APTG-CM) to induce the differentiation of PDLSCs intocementoblast-like cells. This study was aim to work as a basic research for furtherexploring the regulating role of microRNAs during this differentiation process.Object: The aim of this study is to demenstrate the effect of APTG-CM on thedifferentiation of PDLSCs into cementoblast-like cells.Material and Methods: We acquired homogeneous populations of PDLSCs by theapplication of Magnetic-activated cell sorting. Morphological appearance,colony-forming unit efficiency assay and immunocytochemical staining wereevaluated. After induced by APTG-CM, morphological appearance, mineralizationobservation, immunocytochemical staining, alkaline phosphatase activity and geneexpression of cementoblast phenotype of PDLSCs co-cultured with APTG-CM wereevaluated.Results: The positive immunomagetic sorted cells exhibited several characteristics ofPDLSCs, as indicated by colonies forming, morphological characters and positiveimmunocytochemical stainings of STRO-1and CD146. The induced PDLSCs exhibited several characteristics of cementoblast-like cells contrast to the non-inducedgroup, as indicated by high mineralized nodules formation, high ALP activity and theexpression of cementum-related genes and proteins in vitro.Conclusion: Our findings suggest that APTG-CM is able to promote thedifferentiation of PDLSCs into cementoblast-like cells.