Antioxidant and free radicals species in the aqueous humor of patients with age-related cataract

Abstract

Introduction/Objective. Age-related cataract is a significant cause of visual impairment worldwide. Oxidative damage and the effects of free radical species are considered important in the etiopathogenesis of cataracts. The aim of this study was to evaluate the antioxidative capacity and oxidative stress in the aqueous humor according to age and cataracts maturity. Methods. Clinical and biochemical researches were carried out in 55 patients with age-related cataract. According to the cataract maturity patients were classified into incipient (cortical-group C, 18 pts, nuclear-group N, 20 pts) and mature (group M, 17 pts). In order to evaluate the impact of age patients within each group were divided in: Group I (65-69 years) and Group II (70 ? years). The antioxidant activity of aqueous humor was measured by the reduction power (RP) method and the activity of glutathione peroxidase (GPx) spectrophotometrically. Changes in the concentrations of hydroxyl and ascorbyl radicals were detected by electron spin resonance spectroscopy. Results. Both RP and GPx activitiy were significantly (p < 0.001) reduced in group N compared to group C and in group M compared to group N. Concentrations of hydroxyl (29.45 ? 1.01% in group C, 38.12 ? 1.29% in group N and 74.14 ? 2.52% in group M) and ascorbyl radicals (26.12 ? 0.89% in group C, 41.15 ? 1.39% in group N and 83.56 ? 2.84% in group M) increased significantly (p < 0.05) with progression of age-related cataract. Significant negative correlation (r = -0.759, p < 0.05) was determined between concentrations of hydroxyl radicals and content of GPx. Conclusion. Our research proved that the level of oxidative stress in the aqueous humor is significantly affected during aging and cataract progression, The obtained data support the hypothesis that during aging, depending on the maturity of the cataract, the antioxidant capacity in the aqueous humor decreases due to an increase in the concentration of reactive hydroxyl radicals.