Osteoarthritis (OA) is a common chronic joint disease,whose main pathological changes are the degeneration of articular cartilage and secondary bone hyperplasia.The limitation of current treatment methods including pain relief and joint replacement surgery is that they cannot fundamentally improve the damage of articular cartilage.The emergence of disease-modifying osteoarthritis drugs (DMOAD) may break the above limitations.They fundamentally inhibit the structural degeneration of articular cartilage by participating in the regulation of cartilage metabolic balance, regulation of subchondral bone remodeling,and control of local inflammation.Thereby,OA patients will get symptom improvement including pain relief and joint function restoration,delay the artificial joint replacement surgery, and improve the quality of life. There are still no DMOAD drugs widely available on the market worldwide.This paper reviews the background of R&D,the classification of mechanisms of action and research progress of representative drugs under different inechanisms so as to provide reference for future research.

Severe muscle injury is hard to heal and always results in a poor prognosis. Recent studies found that extracellular vesicle-based therapy has promising prospects for regeneration medicine, however, whether extracellular vesicles have therapeutic effects on severe muscle injury is still unknown. Herein, we extracted apoptotic extracellular vesicles derived from mesenchymal stem cells (MSCs-ApoEVs) to treat cardiotoxin induced tibialis anterior (TA) injury and found that MSCs-ApoEVs promoted muscles regeneration and increased the proportion of multinucleated cells. Besides that, we also found that apoptosis was synchronized during myoblasts fusion and MSCs-ApoEVs promoted the apoptosis ratio as well as the fusion index of myoblasts. Furthermore, we revealed that MSCs-ApoEVs increased the relative level of creatine during myoblasts fusion, which was released via activated Pannexin 1 channel. Moreover, we also found that activated Pannexin 1 channel was highly expressed on the membrane of myoblasts-derived ApoEVs (Myo-ApoEVs) instead of apoptotic myoblasts, and creatine was the pivotal metabolite involved in myoblasts fusion. Collectively, our findings firstly revealed that MSCs-ApoEVs can promote muscle regeneration and elucidated that the new function of ApoEVs as passing inter-cell messages through releasing metabolites from activated Pannexin 1 channel, which will provide new evidence for extracellular vesicles-based therapy as well as improving the understanding of new functions of extracellular vesicles.
Creatine/metabolism* ; Extracellular Vesicles ; Muscle, Skeletal/metabolism* ; Myoblasts/metabolism* ; Regeneration ; Connexins/metabolism*