An Assist for Arthritis Studies: A 3D Cell Culture of Human Fibroblast‐Like Synoviocytes by Encapsulation in a Chitosan‐Based Hydrogel

Osteoarthritis (OA) and Rheumatoid arthritis (RA) are the most common arthritis in which the synovium is involved, but the cellular and molecular basis of these pathologies still need better elucidation. Fibroblast-like synoviocytes (FLS), one of the cellular elements of the synovium, play a key role in RA, an autoimmune disease characterized by joint inflammation and systemic symptoms that afflicts 1% of worldwide population. Despite articular damage starts from synovium and then proceeds involving cartilage till bone erosion, several 3D in vitro models are reported for cartilage and bone while only a few studies focused on the synovial component. Here, a hydrogel formulation suitable for 3D culturing human fibroblast-like synoviocytes and evaluated its suitability with non-RA and RA patients derived-cells is developed. Among different formulations, a chitosan (Cs)-based hydrogel, constituted by 70% of Cs and 30% of Matrigel, showed the best results in terms of stability as well as cell growth and morphology: non-RA and RA FLS are able to grow within the hydrogel forming a complex 3D network. Thanks to the low cost, and high market availability of chitosan, this system represents a good alternative to the use of sole Matrigel for encapsulating human synoviocytes.