MMP9 and rheumatoid arthritis: Inhibiting the JAK/STAT pathway to inhibit Th17 differentiation and expression of inflammatory factors (TNF-α, IL-1β, IL-6, IL-17, etc.)in the RA model, promote FLSs apoptosis, inhibit FLSs inflammatory apoptosis, and inhibit the expression of MMP-2 and MMP-9.