软骨ECM凝胶缓释MSC外泌体通过调控腺苷-A2aR-NF-κB轴修复骨软骨缺损的功能及机制研究

骨软骨缺损是导致骨关节炎的重要因素。研究发现在骨软骨缺损修复中，缺损周围软骨细胞的迁移起着重要作用。前期，本团队利用脱细胞技术制备了软骨ECM凝胶，并且蛋白质谱发现该凝胶富含细胞迁移相关蛋白，可促软骨细胞迁移。同时我们发现骨髓间充质干细胞（MSC）外泌体包含大量三羧酸循环相关蛋白，可被软骨细胞摄取而补充能量代谢蛋白，从而恢复软骨细胞ATP水平和合成代谢。进一步研究提示，该功能可能与腺苷A2a受体及其下游NF-κB核移位相关。最后，我们利用前期建立的组织工程技术制备了可稳定缓释MSC外泌体的软骨ECM凝胶。因此，我们假说软骨ECM凝胶通过缓释MSC外泌体调控腺苷-A2aR-NF-κB轴修复骨软骨缺损。本研究拟在体外验证外泌体对软骨细胞的功能，在体内证实组织工程软骨促进软骨再生的能力。从调控能量代谢的角度，阐明软骨ECM凝胶复合MSC外泌体促骨软骨缺损修复的机制。

Osteochondral defect is thought to be an important factor in osteoarthritis. Studies show that in osteochondral repair, the migration of autologous chondrocytes from the edges of defect is of great importance. Previously, we prepared a cartilage ECM hydrogel by utilizing decellularized process. The hydrogel contained cell migration proteins detected by proteomics, and could promote the migration of chondrocytes. Secondly, we found bone marrow stem cell (MSC) exosomes can increase chondrocytes ATP contents by repopulating tricarboxylic acid cycle related proteins and restore anabolic metabolic pathway in chondrocytes. This process may relate with adenosine (ATP hydrolysis) A2a receptor expression and NF-κB nuclear translocation. Finally, we prepared the cartilage ECM hydrogel which could release MSC exosomes stably by using the tissue engineering technology. Therefore, we hypothesized that the cartilage ECM hydrogel-encapsulated MSC exosomes can promote osteochondral repair by regulating adenosine-A2aR-NF-κB axis. This study was designed to verify the function of MSC exosomes on chondrocytes in vitro and confirm the ability of tissue-engineered cartilage in promoting osteochondral repair in vivo. From the perspective of metabolism, we would elucidate the mechanism of osteochondral repair by cartilage ECM/ MSC exosomes hydrogel.