Animal models for rheumatoid arthritis

Abstract

　Rheumatoid arthritis（RA）is autoimmune in nature and characterized by chronic inflammation of the synovial tissue in multiple joints, which leads to joint destruction, although the pathogenesis has not been elucidated completely. Arthritis models are extensively used in investigating the etiological and pathological features of RA, and studies using genetically modified models have been conducted to identify and validate potential targets for treatment. In particular, arthritis models have significantly contributed to the introduction of biologics that inhibit inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Although various animal models, with models of collagen-induced arthritis, are widely used in the development of novel drugs for the treatment of RA, the efficacy of drugs in arthritis models does not necessarily match the therapeutic effect in patients with RA. Whether or not the clinical drug efficacy can be predicted is significantly dependent on the choice of a model system and study protocol. Nevertheless, animal models are indispensable in elucidating the pathological mechanism of RA and in advancing the development of novel therapies. In this review, we will introduce arthritis models that are widely used at present as well as new animal models that have recently begun to be used to discover more innovative drugs for the treatment of RA.