Objectives: To investigate lipid, protein, DNA oxidation and antioxidant status in blood and synovial fluid of rheumatoid arthritis (RA) patients and to determine the importance of oxidative stress parameters in reflecting disease activity.
Design and methods: 20 RA patients and 15 healthy controls were included. Lipid peroxidation (thiobarbituric acid reactive substances (TBARS), lipid hydroperoxide, and conjugated diene), protein oxidation (carbonyl and thiol), DNA oxidation (8-OHdG) and antioxidant status markers (glutathione (GSH), glutathione peroxidase (GSH Px), superoxide dismutase (CuZn SOD), and catalase) were determined in blood and synovial fluid.
Results: TBARS (p<0.001), lipid hydroperoxide (p<0.001), conjugated diene (p<0.001), carbonyl (p<0.001) and 8-OHdG (p<0.01) levels were significantly higher; thiol (p<0.01) and GSH levels (p<0.01) and GSH Px (p<0.001) and CuZn SOD (p<0.01) activities were significantly lower in blood of RA patients. TBARS (p<0.001), lipid hydroperoxide (p<0.001), conjugated diene (p<0.01), carbonyl (p<0.001) and 8-OHdG (p<0.05) levels were significantly higher, catalase activity (p<0.001) significantly lower in synovial fluid of RA patients.
Conclusions: Increased lipid, protein and DNA oxidation markers and impaired antioxidant status confirm the role of oxidative stress in the pathogenesis of RA. Lipid peroxidation markers can serve as surrogate markers for disease activity.