MATRIX METALLOPROTEINASE-2 AND METTALLOPROTEINASE-9 IN CANINE RHEUMATOID-ARTHRITIS

Matrix metalloproteinases (MMPs) are considered important mediators of tissue damage in joint diseases. The levels of MMPs 2 and 9 were meas ured in samples of synovial fluid from 20 joints in seven dogs with rh eumatoid arthritis by gelatin zymography. The results were compared wi th the,actual gelatinolytic activity of the fluid measured in a gelati n-degradation ELISA. The gelatinolytic activity in synovial fluid from arthritic joints was markedly greater than that in fluid from disease -free joints. The zymographic activity attributable to MMP-9 (identifi ed by Western blotting) was absent from synovial fluid from control jo ints but prominent in fluid from arthritic joints, and in these joints the presence of a 75 kDa form of MMP-9 was correlated with the gelati nolytic activity of the fluid measured by the ELISA (r=0.81, P<0.05). Synovial fluid from one dog with rheumatoid arthritis was examined bef ore and after treatment with corticosteroids. After treatment its zymo graphic pattern had returned to normal.