Inflammatory activities of synovial fluids from rheumatoid- and osteo-arthritis to guinea pig skin.
For initial study to examine the chemical pathogenesis of rheumatoid and non-rheumatoid arthritis, the nature and inflammatory activities of 12 synovial fluids from rheumatoid arthritis and 10 from osteoarthritis were studied. Both rheumatoid and non-rheumatoid synovial fluids were found to have high protein concentration, acid and neutral protease activities. When injected 0.1 ml intradermally to normal guinea pig skin, both synovial fluids induced a strong vascular permeability at 0 minutes, mild one at 60 minutes, and mild inflammation which comprised histologically moderate leukocyte infiltration around the venules, swelling of venular endothelial cells, edema, and degeneration of collagen fibrils in the deep dermis of the guinea pig skin 4 hours following the injection. However, these parameters of inflammation induced by synovial fluids from both arthritis were of same degree in intensity. The identification of chemical mediators of inflammation in the synovial fluids of both arthritis requires further study.