Figure 1.

Mesenchymal stem cell therapy strategies in the treatment of OA. (a) Intra-articular injection of MSCs: autologous or allogeneic culture-expanded MSCs are harvested and injected into the articular cavity, where they produce immunomodulatory factors, trophic factors, and extracellular vesicles that induce cartilage defect regeneration and the alleviation of symptoms. (b) Autologous mesenchymal stem cell implantation (AMI): autologous culture-expanded MSCs are implanted back into cartilage defects with fibrin glue. (c) Matrix-assisted autologous mesenchymal stem cell implantation (MAMI): a bioscaffold is applied to the cartilage defect with culture-expanded MSCs.