The Role of Mesenchymal Stem Cell derived Exosomes in Microenvironment of Knee Osteoarthritis*

Osteoarthritis is a degenerative disease of the joints, which involves all components of joints including articular cartilage, subchondral bone, synovium, ligaments, joint capsule, and muscles around the joints. It can lead to severe disability, the most common of which is knee osteoarthritis (KOA). Exosomes are extracellular vesicles with a diameter of 40-100 nm secreted by different cells, which can transmit DNA. microRNA, mRNA, protein and other substances, and carry out intercellular information transmission and function regulation in a variety of ways. Mesenchymal stem cells (MSCs) can be isolated from hone marrow, fat, synovium, peripheral blood and other tissues, and arc a kind of progenitor cells with multi -direction differentiation potential. Stembased therapies can repair cartilage damage and combat the development of KOA. Mesenchymal stem cells can secrete a variety of nutritional factors to regulate the damaged microenvironment, among which exosomes derived from mesenchymal stein cells arc believed to play an important role in the inflammatory response and chondrocyte metabolism of KOA. It can regulate the metabolism of B cells. T cells, synovial cells, chondrocytes and the decomposition and synthesis balance of extracellular matrix in the knee joint microenvironment, and maintain cartilage homeostasis. A number of recent studies have shown that exosomes derived from mesenchymal stein cells from different tissues have definite therapeutic effects on osteoarthritis. This paper reviews the specific mechanism of exosomes derived from MSCs in the treatment of KOA, in order to provide theoretical basis for stem cell treatment of KOA.