MGF在力学刺激促PDLSCs/PRF修复脱位再植牙牙周损伤中的作用及机理研究

Tooth avulsion is a common dental trauma, while its treatment is relatively difficult and hard to forecast. The extensive damage and even necrosis of avulsed periodontal membrane is the key obstacle that prevent the avulsed tooth from obtaining ideal periodontal healing. Clinical experience has shown that the elastic fixation to keep the physiological mobility and occlusal force stimulation of the replanted tooth is essential for periodontal ligament regeneration, but the underlying mechanism keeps unknown. On the basis of the periodontal ligament stem cells (PDLSCs) / platelet rich fibrin (PRF) double-membrane complex construction and application for avulsed tooth replantation in dogs for periodontal healing and regeneration, the project intends to explore the regulation of in vitro and in vivo biomechanical microenvironment for PDLSCs, and further to improve periodontal healing and regeneration by optimizing the growth factors niche and mechanical microenvironment of the PDLSCs, which could provide new promises for the periodontal healing promotion of the replanted tooth after avulsion. With an eye to the mechanical sensitivity of mechano growth factor (MGF) and its existence in periodontal tissues, the project will further probe into the role and underlying signal transduction mechanism of MGF in periodontal healing promotion of injured periodontal tissue after avulsion under in vitro and in vivo biomechanical microenvironment. The whole project is expected to provide a new strategy and method for obtaining ideal periodontal healing of avulsed tooth after replantation, and provide a reference for the studies on some other tissues and organs like periodontal tissue that endures mechanical microenvironment in vivo, as well as for the possible biomechanical regulation for their regeneration and healing after trauma or damage.

牙撕脱性损伤是临床常见且治疗难度较大的一类牙外伤。牙周膜的广泛损伤是脱位牙再植后难以获得理想牙周膜性愈合的关键。本课题组前期成功建立牙脱位再植动物模型，并证明PRF可通过提高PDLSCs等干细胞的活性而获得促牙周再生与修复效果。但动物实验和临床实践都发现对再植牙施以弹性固定以保持其生理动度和咬合力刺激对牙周膜再生仍必不可少,但至今机理不明。我们前期研究证实力敏感分子MGF在牙周组织表达，发现PDLSCs中的MGF基因水平会随PRF的作用而升高，提示MGF可能在牙周损伤修复中扮演重要分子的角色。本课题拟在前期工作基础上以MGF关键分子的功能研究为突破口，利用RNAi、合成肽、基因转染、特异性信号转导通路芯片等技术系统从体内外两方面揭示MGF在力学微环境促PDLSCs /PRF双膜结构再生修复牙周组织过程中所发挥的作用及其信号转导机制。以期为撕脱再植牙获得理想的牙周膜性愈合提供新的策略和思路。

牙撕脱性损伤是临床常见且治疗难度较大的一类牙外伤。牙周膜的广泛损伤是脱位牙再植后难以获得理想牙周膜性愈合的关键。本课题组前期成功建立牙脱位再植动物模型，并证明 PRF 可通过提高 PDLSCs 等干细胞的活性而获得促牙周再生与修复效果。但动物实验和临床实践都发现对再植牙施以弹性固定以保持其生理动度和咬合力刺激对牙周膜再生仍必不可少,但至今机理不明。我们前期研究证实力敏感分子 MGF 在牙周组织表达，发现PDLSCs 中的 MGF 基因水平会随 PRF 的作用而升高，提示 MGF 可能在牙周损伤修复中扮演重分子的角色。本课题在前期工作基础上以 MGF 关键分子的功能研究为突破口，利用 RNAi、合成 肽、基因转染、特异性信号转导通路芯片等技术系统揭示MGF 在力学微环境促 PDLSCs /PRF 双膜结构再生修复牙周组织过程中所发挥的作用及其信号转导机制。研究结果发现：1、周期性动态压力0~120kpa可以有效提高hPDLSCs的增殖活性，并上调hPDLSCs中MGF的表达，MGF在压力加载后24h达到表达高峰。2、本研究探索了压力与MGF对牙周膜干细胞及牙周膜细胞的作用。通过对比我们发现压力及MGF多肽可上调牙周膜干细胞中SCX以及Col-Ⅰ的表达水平。结果提示压力与MGF的主要效应细胞应为牙周膜干细胞，后者参与调控牙周膜干细胞的增殖、牙周膜向分化过程。3、通过免疫荧光及Western-blotting检测发现压力与MGF及MGF-24E可促进牙周膜干细胞中SCX的表达，而对OSX的表达并无显著的促进作用。结果提示压力与MGF及MGF-24E可促进牙周膜干细胞向成牙周膜方向而非成骨方向分化。4、通过抗体芯片及Western-blotting检测相结合的方式，我们发现在压力、压力结合MGF及MGF-24E作用下牙周膜干细胞中非受体型酪氨酸激酶Fyn和Lyn的磷酸化水平升高较为明显，此外细胞中AKT、ERK1/2及p38的磷酸化水平显著高于对照组。从而揭示，压力与压力结合MGF及MGF-24E作用下可激活Fyn或Lyn及其下游信号分子AKT、ERK1/2和p38发挥促牙周膜再生修复的功能。上述研究结果在国内外首次揭示了MGF在牙周组织再生修复过程中所发挥的作用及其相关分子机制，相关成果有望为撕脱再植牙获得理想的牙周膜性愈合提供新的策略和思路。

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