Abnormal proliferation of rheumatoid arthritis synovial fibroblasts (RASF) is recognized as one of the key pathological characteristics of synovitis and secretes large amounts of pro‐inflammatory factors and matrix metalloproteinases (MMPs).[1, 2] Gelatinase MMP‐9, as one of the most important MMPs, plays a critical role in RA inflammation, articular destruction, and bone erosion. Here, MMP9 is linked to rheumatoid arthritis.