Chitosan: A promising polymer for cartilage repair and viscosupplementation.

Osteoarthritis (OA) is a painful, degenerative and inflammatory disease that affects the entire synovial joints. Nowadays, no cure exists, and the pharmacological treatments are limited to symptoms alleviation. There is a need for a new efficient and safe treatment. Viscosupplementation is a process that aims to restore the normal rheological properties of synovial fluid. For the past years, hyaluronic acid was usually used but this molecule has some limitations including the short residency time in joint cavity. Recently, in vitro studies have suggested that chitosan could promote the expression of cartilage matrix components and reduce inflammatory and catabolic mediator's production by chondrocytes. In vivo, chitosan prevented cartilage degradation and synovial membrane inflammation in OA induced rabbit model. Several studies have also shown that chitosan could induce chondrogenic differentiation of mesenchymal stem cells. Therefore, chitosan is an interesting polymer to design scaffold and hydrogel for cartilage lesion repair, cells transplantation, sustained drug release and viscosupplementation.