The Cloning Analysis And Differentiation Ability Of Human's Dental Follicle Cells

The purpose of periodontal therapy is to promote varying degrees of damaged tissue repair and regeneration.How to recover periodontal tissue structure and recover functiona has been pursued by scholars for long time. In recent years, the study of periodontal tissue regeneration has made important progress. Ideal periodontal tissue regeneration should also include the cementum, periodontal ligament and alveolar bone regeneration. The key is to select the appropriate stem cells as seed cells for periodontal tissue engineering.Dental sac originated from outside the ectomesenchymal is surrounding around the enamel organ in the connective tissue, which is the only organ of the formming periodontal tissues. It plays an important role both in the late tooth development and tooth eruption. It is worth considering dental follicle cells a kind of seed cells because of their characteristics in the periodontal tissue differentiation and development. Dental follicle cells, which are direct precursor cells of periodontal tissue development andcan form periodontal ligament, cementum and alveolar inherent bone in late tooth development. And fibroblasts, cementoblasts cells , osteoblasts are all differentiated from them. Dental follicle cells have the ability to form the various parts of periodontal tissues and to divide into multiple directions in a short time. We prosthesis that the cells have some differences for themselves, and they are a kind of heterogeneous cell population. They may contain precursors of periodontal development cellular components with the ability of specific differentiation that can be used as candidate seed cells in periodontal tissue engineering. Therefore, this study begins with the biological characteristics and differentiation characteristics of the dental follicle cells. There is an in-depth understanding in this study of a presence in the periodontal developmental stages of precursor cells by screening a single cell-derived dental follicle cell clones and cloning of its phenotypic analysis. In this study, the feasibility of the dental follicle cells to be applied as seed cells in periodontal tissue engineering is also explored . All of them give some guidances about periodontal tissue regeneration project which the seed cells of are dental follicle cells and build the foundation for the future experimental studies and clinical application .The contents of the present study are as follows:Part I: Isolation and characterization of dental follicle stem cellsMethods: We isolated and cultured human dental follicle stem cells. In vitro,the cells'biological characteristics were detected and compared with human bone marrow-derived mesenchymal stem cells. Results: The two kinds of cells both were fibroblast-like cell lines. DFSCs were shorter, while bone marrow-derived mesenchymal stem cells was more slender; two kinds of cells were negative of CD34, CD45 (hematopoietic cell marker line) expression and were positive of CD29, CD44, CD90, CD105 (mesenchymal cell marker). Compared with BMMSCs, Stro-1 (mesenchymal stem cell-specific markers in the undifferentiated cell populations of high expression) expression, proliferation and colony-forming units of dental follicle stem cells are higher. The capacity of osteogenic differentiation is no significant difference and adipogenic differentiation is low. Conclusion: The DFSCs, as same as BMMSCs, showed a strong characteristics of stem cells in vitro- proliferation activity, clone-forming ability, multi-differentiation capabilities. Both of them came from ectomesenchymal cell; Compared with bone marrow mesenchymal stem cells, dental follicle stem cells contained more undifferentiated cells. Dental follicle stem cells, as seed cells, can be used for optimal regeneration of periodontal tissue engineering applications.Part II: The study of heterogeneity for dental follicle cellsObjective: To study the dental follicle cells heterogeneity. Methods: We used the limiting dilution technique to obtain single-cell-derived clones from human dental follicle cells. The biological characteristics and periodontal tissue regeneration of different clones were observed by analysis of the phenotype. Results: Using limited dilution method we can get single-cell-derived dental follicle cell clones, while there is much difference between the varied biological characteristics of clone phenotypes. Based on the phenotypic analysis of individual clones we can divided them into undifferentiated, fibroblast-type and bone / cementum-type phenotypes, which format specific structures respectively.Conclusion: The dental follicle cells are heterogeneous cell populations, and different phenotype of dental follicle cell clones has the potentiality of formating specific structure of the periodontal tissues. Take advantage of this characteristic, we can not only require a specific structure, but also recombinate different phenotype of clones to build a complete biological active periodontal tissue structure, which is possible in theory.