Interestingly, when the concentration of 4-HNE increased to 50 μM, the mRNA levels of IL1-β, IL-6, and TNF-α in rheumatoid arthritis synovial cells increased gradually with the increasing time up to 1 h and then decreased (Figures 2(d), 2(e), and 2(f)). Here, TNF is linked to rheumatoid arthritis.