TNF and rheumatoid arthritis: Considering that TNF-α and IL-1β are the two key pro-inflammatory cytokines in RA33, the interaction between GMs and inflammatory joint was investigated in a Sprague Dawley (SD) rat model of collagen-induced arthritis (CIA, a commonly used experimental RA model), which was constructed via local injection of complete freund’s adjuvant (CFA) for initial immunization and incomplete freund’s adjuvant (IFA) for inflammation booster in the footpad of a rear paw34.