The clinical significance of gelatinase B in gouty arthritis of the knee

Background: Clinically, gouty arthritis is associated with severe inflammation, such as pain, swelling and erythema of the joints. Gelatinase A and B (matrix metalloproteinase-2 and -9, MMP-2 and -9) participate in the degradation of the extracellular matrix (ECM) components in a variety of arthritis, especially in the inflammatory arthritis. Methods: We examined the levels of MMP-2 and -9 in 40 synovial fluids (SFs) from the knee joints of 24 patients with gouty arthritis and compared them with the clinical and laboratory variables of inflammation. Results: Gelatin zymography revealed that not only activated MMP-2 levels but also proMMP-9 levels in SF from the knee joints of gouty arthritis were associated with the local arthritis activity scores (LAS) (p<0.001) and correlated well with the neutrophil counts in SF as well (p<0.001). A similar correlation between proMMP-9 levels and LAS was also found within the individual patients before and during treatment with nonsteroidal antiinflammatory drugs (NSAIDs; p<0.001). ProMMP-2 appeared in all SFs irrespective of LAS and neutrophil counts. Conclusions: The analysis of MMP-9 in SF samples can reveal the inflammatory condition of the knee joints with gouty arthritis. Joint aspiration may decrease the amount of MMPs in SF to attack the ECM of joint whether it is normal or not.