骨髓间充质干细胞源外泌体通过调控TLR/NF-κB炎症通路修复关节软骨损伤的作用及机制研究

The treatment of osteoarthritis (OA) is difficult in orthopaedics clinic, mesenchymal stem cells (MSCs) have shown benefits for OA treatment, but its application is relatively limited. Mesenchymal stem cell-derived exosomes (MSC-Exo) have similar therapeutic effects as their parental stem cells, with the potential to replace MSCs, which have shown encouraging pro-regenerative and protective properties in various disease models. However, so far it is still not very clear whether MSC-Exo have the similar articular cartilage repair functions as MSCs in OA. Our previous study demonstrated that bone marrow mesenchymal stem cells-derived exosomes (hBMSC-Exo) can repair damaged cartilage in OA mice, but the mechanisms remain unclear. In view of the important roles of inflammation in OA injury process, and the anti-inflammatory functions of MSC-Exo, we postulated that MSC-Exo might repair cartilage injury through inhibiting inflammatory responses in OA. In this project, we will evaluate the repair effects of hBMSC-Exo in OA cartilage injury, to confirm whether hBMSC-Exo can provide a potential therapeutic value to OA, and focus on the influences of hBMSC-Exo on OA inflammation, and preliminarily explore the molecular mechanisms of TLR/ NF-κB signaling pathway involved in the regulation process. The results of the study will provide not only new ideas for prevention and control of OA, but also certain theoretical significances and application values.

骨性关节炎（OA）的治疗一直是临床难点，间充质干细胞（MSCs）为其带来曙光，但应用却受到诸多限制。MSCs源外泌体（MSC-Exo）具有与其来源干细胞类似的功能，有潜力替代MSCs，已在多种疾病中被证实存在促进再生和保护功能。然而，MSC-Exo是否存在与MSCs类似的修复OA关节损伤的作用，至今尚不甚明确。申请人的前期研究初步证实，骨髓间充质干细胞源外泌体（hBMSC-Exo）可修复OA小鼠的关节软骨损伤，但相关机制不明。鉴于炎症在OA损伤中的重要作用以及MSC-Exo的抗炎功能，我们推测MSC-Exo可能通过抑制OA炎症反应来修复软骨损伤。本课题拟通过评价hBMSC-Exo对OA关节损伤的修复效果，确定其是否存在潜在治疗价值，重点关注hBMSC-Exo对OA炎症反应的影响，初步探讨TLR/NF-κB通路参与调控的分子机制。研究结果将为OA的防治提供新思路，具一定的理论意义和应用价值。

为探究干细胞源外泌体对骨性关节炎（OA）的作用效果，重点关注炎症反应在其中发挥的作用和机制。本研究以SD大鼠软骨细胞为OA体外模型，研究发现大鼠骨髓间充质干细胞源外泌体（rBMSC-Exo）可以：（1）促进软骨细胞的迁移运动和增殖能力，抑制其发生凋亡；（2）减少OA软骨细胞ADAMTS-5和MMP-3的表达，增加TIMP-2的表达；（3）增加软骨细胞分化标志基因（Sox-9、COL2A1）的表达，降低肥大化标志基因（Runx2、COL10A1）的表达；（4）抑制OA软骨细胞分泌炎性细胞因子TNF-α、IL-6、CCL2、CCL3、CCL5，并减少NO和PGE2的含量。初步证实TLR3/NF-κB信号通路可能参与调控OA炎症反应，进而减轻软骨细胞损伤。通过内侧半月板撕裂术（MMT）大鼠OA模型证明，rBMSC-Exo可修复OA大鼠关节软骨损伤。综上所述，本研究结果表明，TLR3/NF-κB信号通路在rBMSC-Exo通过抑制炎症反应来修复OA关节软骨损伤的过程中发挥一定的作用。本研究结果为OA的临床防治提供更为广阔的思路，为探索新型“无细胞”治疗方法奠定基础。