In the present study, we have observed a significant decrease in the activity of catalase in patients with osteoarthritis compared to controls. Catalase is an enzyme which protects the cells from accumulation of hydrogen peroxide by dismutating it to form water and oxygen or by using it as an oxidant, in which it works as a peroxidase.
In conclusion, oxidative stress may be involved in osteoarthritis. The results of our study suggest higher oxygen-free radical production and decreased catalase activity, supporting the higher oxidative stress hypothesis in osteoarthritis. The increased activities of antioxidant enzymes may be a compensatory regulation in response to increased oxidative stress. The results suggest the necessity for therapeutic co-administration of antioxidants with conventional drugs to such patients. Therefore, treatment with antioxidants in the initial stages of the disease may be useful as secondary therapy to prevent the oxidative damage and deterioration of the musculoskeletal tissues in osteoarthritis. The findings implicate oxidative stress in the disease and cite the biochemical rationale for clinical trials of antioxidants to prevent and treat osteoarthritis. However, due to the limited number of cases included in this study, more studies may be required to substantiate the results and arrive at a definite conclusion in terms of safety and efficacy of adding antioxidant therapy as secondary therapy for the treatment of osteoarthritis.