Involvement of oxidative stress in patients of gout and antioxidant effect of allopurinol

Background: Various experimental, epidemiological, and clinical studies have shown that hyperuricemia is associated with development of hypertension, visceral obesity, insulin resistance, dyslipidemia, type 2 diabetes, kidney diseases, and cardiovascular and cerebrovascular events. Whether hyperuricemia is a cause or effect is a debatable subject. Although the pathogenesis of these diseases is complex and incompletely understood, it is clear that oxidative stress and damage to proteins and lipids is common for all of them. Objective: To determine whether hyperuricemia causes oxidative stress in patients with gout, and to evaluate the effect of allopurinol treatment on oxidative stress after 1 and 3 months in these patients. Materials and Methods: Patients with newly diagnosed gout (n = 30) and healthy age- and sex-matched volunteers (n = 30) were enrolled in the study. They were treated with 100-mg allopurinol 8 hourly in a day for 3 months. Serum uric acid levels and levels of oxidative stress such as serum malondialdehyde (MDA), erythrocyte catalase (CAT), and erythrocyte superoxide dismutase (SOD) were measured before treatment, and after 1 and 3 months of treatment. Pretreatment levels of all the parameters were compared in both the groups using unpaired t-test. The parameters were also analyzed in test group at 0, 1, and 3 months of treatment using repeated-measures analysis of variance test. Results: Pretreatment levels of serum uric acid and MDA were significantly higher in patients as compared to control group (P o 0.01). They were significantly reduced after 1 (P o 0.05) and 3 months (P o 0.01) of treatment with allopurinol. Pretreatment levels of CAT and SOD were significantly lower in patients as compared to control group (P o 0.01); they were increased significantly after 1 (P o 0.01) and 3 months (P o 0.01) of treatment with allopurinol. Conclusion: From this study, it can be suggested that hyperuricemia causes oxidative stress in patients with gout. Besides the main benefit of lowering serum uric acid level, allopurinol also decreases oxidative stress in patients with gout