[A study on the lipid peroxide and its scavenging enzymes in rheumatoid arthritis (author's transl)].

Superoxide free radical (O2.-) produced by leukocytes, found in a rheumatoid joint, degrade various high molecular polymers in the synovial fluid and thus may play an important role in initiating an inflammatory response. The present work is an attempt to measure the lipid peroxide value as a parameter of peroxidation by O2.- and to measure the activities of superoxide dismutase, catalase and glutathione peroxidase as scavenging enzymes in the serum and the synovial fluid of patients with rheumatoid arthritis and osteoarthritis. The following results were obtained: 1) The lipid peroxide value of the synovial fluid from the rheumatoid arthritic group was found to be higher than that from osteoarthritic group, whereas in the serum no significant difference was found between these two groups. 2) The superoxide dismutase activity of the synovial fluid from the rheumatoid arthritic group was found to be remarkably higher than that from the osteoarthritic group. A significant correlation was also found between the superoxide dismutase activity and the inflammatory indexes, such as C-reactive protein, erythrocyte sedimentation rate, and the number of nucleated cells in the synovial fluid. 3) The catalase activity of the synovial fluid from the rheumatoid arthritic group was increased. 4) No significant difference was found in the glutathione peroxidase activities of the serum and the synovial fluid between the two groups. 5) A positive correlation was found between the lipid peroxide value and the superoxide dismutase activity in the synovial fluid of patients with rheumatoid arthritis. These observations suggest that superoxide free radical may play an important role as a chemical mediator on the inflammatory response of rheumatoid arthritis.