影响牙髓干细胞成骨及成牙本质分化的相关物理因素及作用机制

Physical factors and action mechanisms affecting osteogenic/odontogenic differentiation of dental pulp stem cells

背景:牙髓干细胞是口腔颌面部组织工程中极具应用潜力的干细胞之一,较骨髓间充质干细胞具有采集方便、伦理问题少以及增殖分化潜能高等优势。目前,除了生物化学等因素外,物理刺激对于牙髓干细胞的成骨/成牙本质分化也起着关键性的作用。目的:综述影响牙髓干细胞成骨/成牙本质分化的相关物理因素以及可能涉及的信号传导通路作用机制,寻找影响其分化的最佳诱导条件。方法:检索PubMed和中国知网数据库,以“牙髓干细胞,成骨分化,成牙本质分化,低氧,机械力,激光,磁场,微重力”为中文检索词,以“dental pulp stem cells(DPSCs),osteogenesis differentiation,odontoblastic differentiation,hypoxia,mechanical force,laser therapy,magnetic fields,microgravity”为英文检索词,选取与影响牙髓干细胞成骨/成牙本质分化相关物理因素有关的79篇文献进行综述。结果与结论:(1)微环境中直接或间接的物理信号在调控牙髓干细胞定向分化方面展现出了广阔的应用前景。低氧、力学刺激(动静水压力、机械牵张力及剪切力等)、激光、微重力和磁场等相关物理因素对牙髓干细胞的影响以促进成骨/成牙本质分化为主,因口颌系统拥有复杂的力学环境,力学刺激是细胞环境改变的关键物理因素,同时也是组织工程的一个前沿领域,深入探讨牙髓干细胞对力学环境的响应为口腔疾病的诊断及治疗提供新思路。(2)因该领域比较“年轻”,相关因素涉及的设备参数尚未统一,相关结果存在不一致性,未能达成共识,之后应进一步探索及优化相关物理因素的最佳诱导参数及作用条件。(3)支架材料作为组织工程的三要素之一,在牙髓干细胞成骨/成牙本质分化方面也起到了促进作用,同时也推动了材料学的发展及临床技术的进步。(4)其中涉及到的信号通路有Notch,Wnt,MAPK等,关于物理刺激如何调控牙髓干细胞行为的相关生物学基础尚未明确,未来将进一步探究其具体作用机制,为物理因素影响下的牙髓再生及骨组织工程提供新思路。

BACKGROUND:Dental pulp stem cells are one of the stem cells with great potential in oral and maxillofacial tissue engineering.Compared with mesenchymal stem cells,dental pulp stem cells have the advantages of convenient collection,less ethical problems and higher potential of proliferation and differentiation.Currently,except for biochemical factors,physical stimulation also plays a critical role in the osteogenic/odontogenic differentiation of dental pulp stem cells.OBJECTIVE:To review the relevant physical factors and the possible signaling pathway affecting the osteogenic/odontogenic differentiation of dental pulp stem cells to find the optimal induction conditions affecting their differentiation.METHODS:PubMed and CNKI databases were searched for relevant articles using“dental pulp stem cells(DPSCs),osteogenesis differentiation,odontoblastic differentiation,hypoxia,mechanical force,laser therapy,magnetic fields,microgravity”as English and Chinese search terms.Seventy-nine articles regarding physical factors affecting osteogenic/odontogenic differentiation of dental pulp stem cells were selected for the review.RESULTS AND CONCLUSION:(1)Direct or indirect physical signals in the microenvironment have shown broad application prospects in regulating the directed differentiation of stem cells.Many related physical factors,for example,hypoxia,mechanical stimulation(dynamic hydrostatic pressure,mechanical tension,shear force,etc.),laser,microgravity,and magnetic field,have positive influences on the osteogenic/odontogenic differentiation of dental pulp stem cells.Owing to the complex mechanical environment of stomatognathic system,mechanical stimulation is a key physical factor in changing cellular environment and is also a frontier in tissue engineering.It will provide new ideas for investigating the response of dental pulp stem cells to the mechanical environment in the diagnosis and treatment of oral diseases.(2)Because this field is relatively“young”,the parameters of equipment have not been unified and the relevant results are not consistent.The optimal induction parameters and conditions of related physical factors should be further explored and optimized.(3)Scaffold material,one of the three elements of tissue engineering,plays a role in promoting the osteogenic/odontogenic differentiation of dental pulp stem cells,and promotes the development of materials science and clinical technology.(4)The signaling pathways involve Notch,Wnt,MAPK,etc.The biological basis of regulating the behavior of dental pulp stem cells is not clear.The specific mechanism will be further explored in the future to provide new ideas for dental pulp regeneration and bone tissue engineering under the influence of physical factors.