Overexpression of Glyoxalase-I Reduces Hyperglycemia-induced Levels of Advanced Glycation End Products and Oxidative Stress in Diabetic Rats

• DOI: 10.1074/jbc.m110.144097
• Publication Date: 2010-11-06T01:10:37Z
• Authors: Olaf Brouwers; Petra M. Niessen; Isabel Ferreira; Toshio Miyata; Peter G. Scheffer; Tom Teerlink; Patrick Schrauwen; Michael Brownlee; Coen D. Stehouwer; Casper G. Schalkwijk
• Keywords: Glycation End Products, Advanced; 0301 basic medicine; 571; Social and Behavioral Sciences; Gene Expression Regulation, Enzymologic; Oxidative Phosphorylation; Diabetes Mellitus, Experimental; 03 medical and health sciences; Pregnancy; Methylglyoxal; Medicine and Health Sciences; Animals; Humans; Endothelium; Rats, Wistar; Glycation; Diabetes; Lactoylglutathione Lyase; Glyoxal; Pyruvaldehyde; Glyoxalase-1; Mitochondria; Rats; 3. Good health; Disease Models, Animal; Oxidative Stress; Metabolism; Oxidative stress; Hyperglycemia; Rat; Female; Rats, Transgenic; Biomarkers

The reactive advanced glycation end product (AGE) precursor methylglyoxal (MGO) and MGO-derived AGEs are associated with diabetic vascular complications and also with an increase in oxidative stress. Glyoxalase-I (GLO-I) transgenic rats were used to explore whether overexpression of this MGO detoxifying enzyme reduces levels of AGEs and oxidative stress in a rat model of diabetes. Rats were made diabetic with streptozotocin, and after 12 weeks, plasma and multiple tissues were isolated for analysis of AGEs, carbonyl stress, and oxidative stress. GLO-I activity was significantly elevated in multiple tissues of all transgenic rats compared with wild-type (WT) littermates. Streptozotocin treatment resulted in a 5-fold increase in blood glucose concentrations irrespective of GLO-I overexpression. Levels of MGO, glyoxal, 3-deoxyglucosone, AGEs, and oxidative stress markers nitrotyrosine, malondialdehyde, and F2-isoprostane were elevated in the diabetic WT rats. In diabetic GLO-I rats, glyoxal and MGO composite scores were significantly decreased by 81%, and plasma AGEs and oxidative stress markers scores were significantly decreased by ∼50%. Hyperglycemia induced a decrease in protein levels of the mitochondrial oxidative phosphorylation complex in the gastrocnemius muscle, which was accompanied by an increase in the lipid peroxidation product 4-hydroxy-2-nonenal, and this was counteracted by GLO-I overexpression. This study shows for the first time in an in vivo model of diabetes that GLO-I overexpression reduces hyperglycemia-induced levels of carbonyl stress, AGEs, and oxidative stress. The reduction of oxidative stress by GLO-I overexpression directly demonstrates the link between glycation and oxidative stress.