[Levels of matrix metalloproteinase-3 and urokinase-type plasminogen activator in knee synovial fluids from patients with rheumatoid arthritis and osteoarthritis].

The objective of this study is to determine the levels of matrix metalloproteinase-3 (MMP-3) and urokinase-type plasminogen activator (uPA) in knee synovial fluids from patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Knee synovial fluids were collected from patients with RA and OA. Concentrations of MMP-3 were determined by enzyme immunoassay using a pair of monoclonal antibodies against human proMMP-3, and activities of uPA were measured by immunocapture assay using a polyclonal antiserum against human uPA. The median concentration of MMP-3 in synovial fluids was 97.5 +/- 82.6 micrograms/ml (range 1.06-336 micrograms/ml) for RA group and 20.5 +/- 11.3 micrograms/ml (range 6.19-42.8 micrograms/ml) for OA group. Levels of MMP-3 were significantly higher in RA group than in OA group. The median activity of uPA in synovial fluids was 0.053 +/- 0.052 i.u./ml (range 0.003-0.187 i.u./ml) for RA group and 0.072 +/- 0.059 i.u./ml (range 0.006-0.169 i.u./ml) for OA group. No significant difference of uPA activity was observed between RA and OA group. Significant correlation of the levels of MMP-3 with those of uPA was observed in RA group, however not in OA group. The increased levels of MMP-3 in synovial fluids in RA group may reflect an elevated matrix degrading activity due to joint inflammation. The significant correlation of MMP-3 with uPA in RA group suggests that MMP-3 could degrade cartilage matrix more actively in conjunction with PA-plasmin system than MMP-3 alone.