RESUMO
Aim To observe the immune regulation and cartilage protection of dexamethasone-loaded thermosensitive hydrogel (DLTH) on rheumatoid arthritis (RA) rats via conceiving a newly injectable sustained DLTH with chitosan-glycerin-borax as carrier. Methods Thirty rats were randomly divided into three groups, namely control, model and DLTH group. RA model was established through immune induction in model and DLTH group. From the 12th day, rats of DLTH group were injected with 40 (jlL DLTH (1 mg · kg
RESUMO
Arthritis is a common chronic disease characterized by the destruction of joint cartilage and inflammation in the sur-rounding tissues. Although it is known that the pathogenesis of arthritis is influenced by a series of factors, the underlying mechanisms remain unclarified. Recently, increasing attention has been paid to the increase of matrix metalloproteinases (MMPs) in articular cartilage,resulting in an inevitable degra-dation of cartilage and extracellular matrix (ECM). MMP-13, the major functioning enzyme during arthritis development,plays a vital role in the cartilage destruction, thus contributing to the decomposition of type Ⅱ collagen irreversibly. A variety of cellu-lar cytokines such as IL-1β and TNF-α,and Runx2 are assumed to affect the expression of MMP-13 in chondrocytes. The hypom-ethylation of the promoter region of the MMP-13 may induce its expression, while it can be reduced by inhibiting histone acety-lation. Meanwhile, microRNA can reduce the expression of MMP-13. In conclusion, MMP-13 can be used as an important therapeutic target in arthritis. In this review, we focus on the role of MMP-13 in arthritis and its underlying regulatory mecha-nisms.