颞下颌关节骨关节炎是口腔颌面外科的多发病和常见病，其发病机制复杂，治疗效果不佳。课题组长期致力于颞下颌关节疾病的临床和基础研究，已证明经ALK5转染的BMSCs对小鼠膝关节骨关节炎具有治疗作用，并对其机制进行了初探。基于此，本项目拟通过光控细胞薄层技术，获取经ALK5转染的BMSCs细胞片和终末分化软骨细胞片，观察共培养下的BMSCs分化及软骨细胞转归，分析Smads通路相关因子和炎症因子的时空表达及两者间相互关系；同时，验证BMSCs细胞片促软骨细胞的损伤修复作用，阐明ALK5转染的BMSCs是否通过激活Smad2/3信号通路、阻断IL1、IL6、TNF-а、MMP-13，从而延缓骨关节炎症发生；构建TMJOA动物模型，验证ALK5转染的BMSCs在体内条件下对TMJOA的治疗作用。本项目的开展将阐明ALK5/Smad信号传导通路在TMJOA发生、发展中的作用，为其临床治疗提供实验依据。

Temporomandibular joint osteoarthritis (TMJOA) is a frequently-occurring and common disease of oral and maxillofacial surgery. Our research group has devoted to the temporomandibular joint disease on clinical and basic research for long term and has proven the ALK5-transfected BMSCs have the therapeutic effect on knee joint osteoarthritis in mice. Besides, the regulation mechanism has carried on the preliminary study. On this basis, the project plans to apply the light-induced cell sheet technology to obtain the ALK5-transfected BMSCs cell sheet and terminally differentiated chondrocytes sheet to observe the differentiation of BMSCs and the outcome of cartilage cells under the co-culture, and to analyse the differentiation of BMSCs and the terminal differentiation of chondrocytes, and the temporal and spatial expression of the upstream and downstream factors in the Smads pathway and the inflammatory factors. At the same time, in order to validate that the BMSCs cell sheet can promote cartilage damage repair function and to clarify whether ALK5-transfected BMSCs can activate Smad2/3 signaling pathways, block IL1, IL6 and TNF-а, MMP-13 and delay joint inflammation; Furthermore, TMJOA animal model was constructed to further verify the therapeutic effect of the ALK5-transfected BMSCs on TMJOA in vivo. The purpose of this project is to clarify the role of ALK5/Smad signaling pathway in TMJOA, and to provide experimental basis for clinical treatment of TMJOA.