Effects of Valine and Leucine on Some Antioxidant Enzymes in Hypercholesterolemic Rats

Abstract

Objective: Reactive oxygen species (ROS) are involved in the endothelial-mediated disorders within atherosclerosis. Considering that an oxidant/antioxidant imbalance might be a key factor in the damaging ROS-mediated effects, the present study intends to determine the influence of a high-fat diet, associated with essential amino acids—valine and leucine, upon the experimental animals, through evaluation of plasmatic level of some antioxidant enzymes. Material and Methods: The study was conducted on 32 male Wistar rats, which were fed with cholesterol, valine and leucine, for 60 days. The animals were divided into four groups, according to the received diet: the first group—standard diet; the second group—cholesterol (C); the third group—cholesterol and valine (C + V); the fourth group—cholesterol and leucine (C + L). Evaluations of the oxidative status, through plasma levels of the antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidise (GPx), were made for the four mentioned groups of animals, at the beginning of the study (R0), after one (R1) and two months (R2). Results: The average values of SOD and GPx in group of animals fed exclusively with cholesterol (C) were significantly higher compared to the third group where cholesterol was supplemented with valine (C + V) or fourth group fed with cholesterol and leucine (C + L) (p < 0.001), after one month as well at the end of the experiment (two months). There were no significant differences in the levels of SOD and GPx between group III and group IV (p < 0.05) at the end of the experiment. Conclusion: Our results showed that valine and leucine decreased the serum levels of SOD and GPx and therefore they were useful antioxidants, which could improve the endothelial dysfunctions associated with atherosclerosis. Moreover, analysis of the oxidative status in the context of atherosclerotic mediated endothelial damage suggests that deviation from normal to alter endothelial status may be conditioned by an oxidants/antioxidants imbalance.