Eales' disease: increased oxidation and peroxidation products of membrane constituents chiefly lipids and decreased antioxidant enzymes and reduced glutathione in vitreous

Abstract

PURPOSE. To measure the levels of oxidation and peroxidation products of membrane constituents chiefly lipids produced by oxygen and lipid free radicals as thiobarbituric acid reacting substances (TBARS), reduced glutathione (GSH) and the antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GP) in vitreous samples from patients with Eales' disease and estimate GSH, SOD, GP in the erythrocytes of patients with Eales' disease with active perivasculitis and healed perivasculitis. METHODS. Vitreous samples on vitrectomy from 11 patients with Eales' disease and 11 patients with diabetic vitreous hemorrhage were used for comparison. For study on erythrocytes, 30 patients of Eales' disease at the active vasculitis stage (group-I), 33 of healed vasculitis stage (group-II) and 25 controls (group-III) were used. The male female ratio was kept the same among the patients and the controls. Oxidation and peroxidation products of membrane constituents chiefly lipids were estimated as TBARS, SOD by its activity to inhibit auto-oxidation of epinephrine, GP by estimating the reduction in the level of GSH and GSH by its colour reaction with 5,5'-dithio bis (2-nitro) benzoic acid (DTNB). RESULTS. TBARS were increased 6 fold in the vitreous of Eales' patients compared to the samples from those with diabetic vitreous hemorrhage while there was a reduction of 95.9% of SOD and 84.2% of GSH. Activity of SOD, GP and the levels of GSH in the erythrocytes were reduced (%) by 81.6, 65 and 56.5 respectively in group I and 22,46.4 and 29.2% respectively in group II. The values are statistically significant. CONCLUSIONS. Increased levels of TBARS and decreased levels of SOD and GSH in the vitreous could explain inflammation, retinal damage and neovascularization in patients with Eales' disease. Decrease of SOD, GP and GSH is found in erythrocytes both in the active perivasculitis stage and the healed perivasculitis stage. Treatment of Eales' disease with antioxidants vitamin E, C as also vitamin A may have a beneficial effect.