软骨细胞来源外泌体在TMJ OA退变软骨异常钙化中的作用和机制研究

Exosomes play an important role in many physiological and pathological processes. But little is known about the influence of exosomes in occurrence and development of osteoarthritis (OA), especially exosomes derived from chondrocytes. Recently, we established temporomandibular joint (TMJ) OA rat model by abnormal occlusion. In degenerative cartilage, differentiation of chondrocytes and deposition of calcium-containing crystals were both accelerated, together with the existence of massive exosomes. In addition, stimulated by fluid shear stress, the secretion of exosomes derived from chondrocytes was enhanced, followed by accelerated chondrocytes differentiation and calcium-containing crystals deposition. In this study, we will use the TMJ OA rat model and isolated TMJ chondrocytes with in vitro biomechanical loading combined, to claim that abnormal biomechanical force could enhance the secretion of chondrocytes-derived exosomes, in which the content of pro-calcification molecules and pro-differentiation molecules were also increased, to promote the calcium-containing crystals deposition and chondrocytes differentiation in osteoarthritic cartilage of TMJ. By the above exploration, a new target for OA treatment will be provided.

外泌体（Exosome）在众多生理和病理过程中均发挥了重要的调节作用，但是目前对外泌体在骨关节炎（OA）发生及发展过程中的影响所知甚少，尤其是软骨细胞来源外泌体尚无研究报道。我们前期研究发现在异常咬合所致大鼠颞下颌关节骨关节炎（TMJ OA）退变软骨中存在异常钙化和软骨细胞异常分化的现象，同时退变软骨中存在大量外泌体；体外对髁突软骨细胞施加流体剪切力刺激后外泌体分泌增多，同时细胞分化和钙盐沉积加剧。本项目拟以TMJ OA模型大鼠为研究对象，同时结合体外细胞力学加载实验，以期论证异常生物力刺激可导致软骨细胞外泌体分泌增多，同时外泌体中促钙化分子和促细胞分化分子含量增多，加速TMJ OA软骨中异常钙盐沉积和细胞异常分化，为OA防治提供新的思路。

外泌体（Exosome）在众多生理和病理过程中均发挥了重要的调节作用，但是目前对外泌体在骨关节炎（OA）发生及发展过程中的影响所知甚少，尤其是软骨细胞来源外泌体尚无研究报道。本项目以UAC异常咬合致TMJ OA大鼠为研究对象，结合体外软骨细胞流体剪切力加载实验，对外泌体及其内含蛋白进行干预，观察TMJ软骨异常钙化的情况。发现在UAC异常咬合所致大鼠TMJ OA退变软骨中存在异常钙化，同时钙化区域软骨中存在大量外泌体；对体外培养的TMJ髁突软骨细胞施加流体剪切力刺激后外泌体分泌增多且外泌体内蛋白成分（MGP、TNAP、NPP1）含量改变，同时细胞钙化加剧；抑制TMJ髁突软骨细胞外泌体形成或对外泌体内蛋白（MGP、TNAP、NPP1）进行相应改变可以有效缓解流体剪切力诱导的细胞钙化；对正常培养的TMJ髁突软骨细胞施加外泌体，可以促进细胞钙化的产生；对UAC大鼠进行TMJ局部注射外泌体抑制剂可以缓解TMJ OA软骨退变和钙化；对正常大鼠进行TMJ局部注射外泌体可以诱发类似TMJ OA的软骨退变和钙化。本项目证实异常生物力刺激可导致软骨细胞外泌体分泌增多，同时外泌体中促钙化分子含量增多、抑钙化分子含量下降，进而加速TMJ OA软骨中异常钙化，针对外泌体及其内含蛋白进行干预治疗将有望为OA防治提供新的思路。