TNF and rheumatoid arthritis: In our previous study, we found that TCDCA could be used to combat adjuvant arthritis by inhibiting the expression of pro-inflammatory cytokines, such as interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and induce apoptosis of fibroblast-like synoviocytes (FLS) [7,8,18], which suggested that TCDCA may be a potential therapeutic agent for rheumatoid arthritis (RA) or other inflammatory diseases.