Decreased inhibition of proteolysis by osteoarthritic synovial fluids.

The hypothesis, that part of the pathogenesis of osteoarthritis may be due to the diminished ability of the osteoarthritic synovial fluid to restrict proteolysis, has been tested by a functional biochemical assay for such inhibitory activity. The results from six synovial fluids from normal or mildly osteoarthritic knees were compared with those from seven from joints showing moderately severe or severe osteoarthritis. Whether on the basis of 'per mg protein' or 'per millilitre' of the fluids, the latter showed a clearly diminished capacity for inhibiting proteolysis under the conditions of this assay.