Therapeutic effects of bone marrow mesenchymal stem cells‐derived exosomes on osteoarthritis

Mesenchymal stem cells (MSCs) have shown chondroprotective effects in clinical models of osteoarthritis (OA). However, effects of MSC‐derived exosomes on OA remain unclear. The study aimed to investigate the therapeutic potential of exosomes from human bone marrow MSCs (BM‐MSCs) in alleviating OA. The anterior cruciate ligament transection (ACLT) and destabilization of the medial meniscus (DMM) surgery were performed on the knee joints of a rat OA model, followed by intra‐articular injection of BM‐MSCs or their exosomes. In addition, BM‐MSC‐derived exosomes were administrated to primary human chondrocytes to observe the functional and molecular alterations. Both of BM‐MSCs and BM‐MSC‐derived exosomes alleviated cartilage destruction and subchondral bone remodelling in OA rat model. Administration of BM‐MSCs and exosomes could reduce joint damage and restore the trabecular bone volume fraction, trabecular number and connectivity density of OA rats. In addition, in vitro assays showed that BM‐MSCs‐exosomes could maintain the chondrocyte phenotype by increasing collagen type II synthesis and inhibiting IL‐1β–induced senescence and apoptosis. Furthermore, exosomal lncRNA MEG‐3 also reduced the senescence and apoptosis of chondrocytes induced by IL‐1β, indicating that lncRNA MEG‐3 might partially account the anti‐OA effects of BM‐MSC exosomes. The exosomes from BM‐MSCs exerted beneficial therapeutic effects on OA by reducing the senescence and apoptosis of chondrocytes, suggesting that MSC‐derived exosomes might provide a candidate therapy for OA treatment.