[Intra-articular nitric oxide levels in patients with rheumatoid arthritis].

The aim of this study was the appraisal of the nitrite and nitrate levels in the synovial fluid of patients with rheumatoid arthritis (RA). The synovial fluid of patients with osteoarthritis (OA) was also evaluated by comparison. Demographic characteristics such as age and sex, and clinical and laboratorial parameters like duration of disease, functional class and erythrocyte sedimentation rate (ESR) were evaluated too. In the synovial fluid of all patients the total and differential leukocyte count, and the nitrite and nitrate levels determined by Griess reaction were analyzed. The results were statistically analyzed by Student's t test and correlation test. We found a significant increase in the intraarticular nitrite and nitrate levels in patients with RA when compared with OA patients (30.68 +/- 2.94 microM x 16.15 +/- 2.73 microM). We did not find any correlation between intraarticular nitrite and nitrate levels and the ESR or the total and differential leukocyte count in the RA synovial fluid. In this study we clearly found an increase in the intraarticular nitrite and nitrate levels in patients with rheumatoid arthritis.