SummaryTo better understand the mechanisms responsible for the pathological processes of osteoarthritis (OA) and to potentially identify a profile of changes that could be predictive of early OA, matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in the synovial fluid and serum of normal and osteoarthritic dogs were examined. The concentration of MMP-1 in the synovial fluid of osteoarthritic dogs (0.62 ± 0.16), as measured by densitometry, was significantly higher than that found in control dogs (0.42 ± 0.19) (P = 0.03). The concentration of MMP-1 in the serum of osteoarthritic dogs (0.74 ± 0.16) was significantly less than that found in control dogs (0.87 ± 0.08) (P = 0.05). The concentration of TIMP-2 in the synovial fluid of osteoarthritic dogs (46.2 ± 21.9 ng/ml) was significantly less than that of control dogs (122.0 ± 66.5 ng/ml) (P = 0.009). The concentration of TIMP-2 in the serum of osteoarthritic dogs (116.2 ± 43.1 ng/ml) was not significantly different than that of control dogs (95.1 ± 94.4 ng/ml) (P = 0.554). In addition, a phospho-tyrosine immunoprecipitation and mass spectrometry were used to isolate and identify interferonalpha in canine synovial fluid.
Study of Latent Matrix Metalloproteinase- 1 Activity in Serum and Synovial Fluid of Patients with Rheumatoid Arthritis