The Effect Of Human Dental Pulp Stem Cells-conditioned Med Medium On The Process Of Osteogenic Differentiation Of Human Dental Follicle Stem Cells In Vitro

Objective: Dental follicle is an ectomesenchymal tissue surrounding the enamel organ and the dental papilla of the developing tooth germ prior to eruption.This tissue contains progenitor cells that form the periodontium,i.e.,cementum,PDL,and alveolar bone.Precursor cells have been isolated from human dental follicles of impacted third molars.Similar to other dental stem cells,dental follicle stem cells possess pluripotent differentiation and self-renewal capacity.It is suggested that stem cell niche represented a specialized microenvironment housing the stem cell and assuring its continued existence,i.e.,the support cells within the niche with their secretory products would govern stem cell behavior.Many studies have attempted to provide biomimicking environments which are suitable for stem cell culture and differentiation.A dental pulp cells-conditioned medium holds the potential to serve this role.Thus the study is to evaluate the effects of human dental pulp cells-conditioned medium(HDPCs-CM)on osteogenic differentiation of human dental follicle stem cells(HDFSCs)in vitro.Methods:1.HDFSCs were acquired by a collagenase digestion method.Monoclonal method,immumofluorescence method and flow cytometry were used to purify,identify the sources and phenotype of cells.2.Prepare the human dental pulp cells-conditioned medium(HDPCs-CM).The morphological changes of HDPCs-CM induced HDFSCs were observed;3.CCK-8 was applied to evaluate the changes of HDFSCs viability of seven days after HDFSCs were induced by HDPCs-CM;4.The osteogenic differentiation was studied by alkaline phosphatase(ALP)staining and alizarin red staining.5.The expression of POSTN,Col?,ALP,BSP and OPN m RNA was detected by Real-Time PCR.Results:1.HDFCSs are successfully harvested and evaluated.2.Induced by HDPCs-CM,HDFSCs exhibited several characteristics of cementoblast or osteoblast lineages.3.From the next day,the viability of HDFSCs in induced group has been significantly inhibited(P<0.05 or P<0.01).4.After osteogenic induction,ALP staining was stronger and there were more mineralized nodules in induced group.5.The expression level of POSTN,Col?,ALP,BSP and OPN were upregulated(P<0.05 or P<0.01)in the induced group.Conclusion: Our findings suggest that HDPCs-CM is able to provide a periodontal microenvironment and induce osteogenic differentiation of HDFSCs.This has significant implications for periodontal engineering.