Effect of Glutamine on Oxidative Stress, Inflammatory, and Glycation Markers, and the Activity of Glyoxalase System in Diabetic Rats with Atherosclerosis

Vascular complications of diabetes are the most common causes of mortality in diabetic patients. Hyperglycemia, insulin resistance, dyslipidemia, glycation products, oxidative stress, and inflammation lead to atherosclerosis and diabetic nephropathy in diabetes. This research aimed at studying the effect of glutamine (Gln) on main causes of vascular complications in diabetic rats with atherosclerosis. In this experimental study, 40 male Wistar rats were divided into four groups, including a control group, diabetic atherosclerosis group, and two similar groups under Gln (0.1% in drinking water) treatment. The following items were measured in all groups: fasting blood sugar, insulin, insulin resistance index, lipid profile, the activity of glyoxalase system (GLO), markers of glycation (glycated albumin, glycated LDL, glyoxal, methylglyoxal, and advanced glycation end products), oxidative stress markers (malondialdehyde and advanced oxidation end products), inflammatory markers (interleukine-6 and tumor necrosis factor-α), serum creatinine, 24-hour urine protein excretion, and kidney weight index. In diabetic-atherosclerotic group Gln reduced fasting blood sugar, insulin resistance, triglyceride level, total cholesterol, atherogenic index, markers of glycation, oxidative stress, and inflammation. The levels of Cr, 24-hour urine protein excretion, and kidney weight index were lower in treated diabetic-atherosclerotic rats than the untreated group. Gln showed elevating effect on the activity of GLO system in diabetic-atherosclerotic group (p< 0.001). Glutamine improved glucose and lipid metabolism, reduced glycation, oxidative stress, and inflammation and induced the activity of glyoxalase system. Therefore, it could have preventive effect on vascular complications of diabetes.