Glycine restores glutathione and protects against oxidative stress in vascular tissue from sucrose-fed rats

The attenuation of oxidative stress could be an important mechanism whereby the incidence of vascular complications in the metabolic syndrome may be diminished. This work was undertaken to investigate the mechanism by which glycine, supplemented to the diet of sucrose-fed (SF) rats, modulates glutathione biosynthesis and protects against oxidative stress and altered endothelium-dependent relaxation in isolated aorta. Glycine reduced superoxide anion release in the presence of NADPH, and decreased protein carbonyl and lipid peroxidation. This glycine effect can be due to increased amount of glutathione synthetase which may be responsible of increased glutathione (GSH) content in vascular tissue from SF rats. Glycine, moreover, increased the amount of Cu/Zn-SOD and eNOS in aorta from SF animals. Last, it improved the relaxation response to acetylcholine found impaired in aortic rings from SF rats. In the presence of N-acetyl-cysteine, a precursor of reduced glutathione, an improved acetylcholine-mediated aortic relaxation of aortic rings from SF rats was observed, while buthionine sulfoximine, an inhibitor of glutathione biosynthesis, inhibited the relaxing effect of N-acetyl-cysteine in aortas from both control and SF rats. This experiment emphasizes the role of GSH in endothelial function in SF rats. The present data suggest that glycine rectifies vascular reactivity by increasing the biosynthesis of glutathione. Glutathione protects vascular tissue against oxidative stress, ...
Source: Clinical Science - Category: Biomedical Science Authors: Source Type: research