The Study Of PDLSCs-mediated T Cell Apoptosisunder The Static Pressure

Mechanical force is relevant to tooth movement through the biological responses of cells in the alveolar bone, periodontal ligament and other paradental tissues.Tooth movement by the application of orthodontic force is characterised by remodelling changes in periodontal tissues such as the periodontal ligament and alveolar bone. The host response toorthodontic force has been described as an aseptic andtransitory inflammation, mediated by a variety of endogenous mediators such as cytokines and chemokines, which are involved in adaptive and innate immunity. Chemokines are a superfamily of small chemotactic cytokinesrecognized as regulators of inflammatory reactions, andthe development of an appropriate immune response byco-ordinating leucocyte recruitment.During the orthodontic tooth movement,PDLSCs play an important action.Periodontal ligament stem cells(PDLSCs) from periodontitis tissue had impaired immunomodulatory function, which may lead to an imbalanced immune response and the acceleration of osteoclastogenesis and inflammation related bone loss. PDLSCs and other tooth-related stem cells have provided new prospects and potential therapeutic cell sources for tooth regeneration and the reconstruction of periodontal ligament tissue damaged by periodontal diseases. However, limited cell sources of autologous dental stem cell populations impede the potential of clinical application. Allogeneic dental stem cells significantly enlarged the source of seed cells for teeth and periodontal tissue regeneration and reconstruction development. Allogeneic PDLSCs exhibited immunosuppressive activities on activated T-cells in vitro. In vivo allogeneic PDLSCs can regenerate and reconstruct periodontal ligament damaged by periodontal diseases and inactivate T-cell immunity.Part I Building the model of rat orthodontic tooth movement and the investigating the expression of nestin and CD3 in the area of PDLSC.Objective Building the model of rat orthodontic tooth movementand investigate the nestin and CD3 in the area of PDLSC.Methods 1) Building the model of rat orthodontic tooth movement, 2) Investigate the nestin and CD3 in the area of PDLSC.Results PDLSCs and Tcell participateorthodontic tooth movement. ConclusionsConclusions r PDLSC and r Tcell participate the procedure of rat orthodontic tooth movement.Part II Mechanical stress-activated immune response ObjectiveUnderstanding themechanotransduction of tooth movement to immune activation,Methods 1) r PDLSCs cultured in vitro were incubated under continuous static pressure of 100 kpa for 1 h and 12 h.2) The expression of apoptosis related protein Fas and Fas L in rPDLSCs were tested by Western Blot.Results 1) Under the static pressure of 100 Kpa for 1 h, both the expression of the apoptosis related protein Fas and Fas L increased more significantly than that of the controls(P<0.05)2) The expressions of the apoptosis related protein Fas and Fas L decreased more significantly than that of the controlswhen the static pressure continued for 12 h(P<0.05).Conclusions Continuous staticpressure of 100 kpa for 1 h promotes apoptosis, while continuousstatic pressure of 100 kpa for 12 h inhibits apoptosis.Part III Rat periodontal ligament stem cells(r PDLSCs) induce r Tcell apoptosis under the stress.Objective Investigate theapoptosis level of r TcellMethods Theapoptosis level of r Tcell was determined by Flow cytometry.Results 1) Under the static pressure of 100 Kpa for 1 h, both the expressions of the apoptosis related protein caspase-3 and caspase-8 and the level of apoptosis higher than that of the controls(P<0.05).2) The expression of the apoptosis related protein caspase-3 and caspase-8 decreased more significantly than that of the controlswhen the static pressure continued for 12 h(P<0.05).Conclusions 1) Rat periodontal ligament stem cells(r PDLSCs) induce r T-cell apoptosis. 2) Ratperiodontalligament stem cells(r PDLSCs) induce T-cell apoptosis via FAS Ligant.