Analysis of lens redox status in cataracts from rat models of type 1 and 2 diabetes

Abstract

Purpose. To identify differential changes in redox status underlying type 1 (T1DC) and type 2 (T2DC) diabetic cataract (DC) formation in rat.Material and methods. Rat models of type 1 and 2 diabetes were respectively induced, and cataract progression was examined weekly. At week eight the levels of reduced glutathione (GSH), oxidized glutathione (GSSG), nicotinamide adenine dinucleotide 2’-phosphate reduced tetrasodium salt (NADPH), and glucose-6-phosphate dehydrogenase (G6PD) activity were measured and compared with those in controls.Results. Cataracts were observed two more weeks earlier in type 1 than type 2 diabetic rats. Furthermore, cataracts were progressed more slowly in T2DC compared with those in T1DC. Lens GSH levels were decreased 4-fold and 2-fold in type 1 and type 2 diabetic rats, respectively, compared with levels in normal control rats. NADPH levels were showed 2.4-fold and 1.5-fold decreases in type 1 and 2 diabetic rats, respectively, compared with normal controls. Similar changes were found in the activity of G6PD.Conclusions. The results suggest that GSH and NADPH loss might be important pathological mechanisms in T1DC and T2DC formation. The «fast» progression of cataracts in type 1 diabetic rats might be due to the more severe oxidative stress than in type 2 diabetic rats.

Keywords

• cataract
• model in rat
• type 1 and type 2 diabetes mellitus
• redox oxidative status