Vascular endothelial function is improved by oral glycine treatment in aged rats.
Jaime H. Gómez-Zamudio Revue canadienne de physiologie et pharmacologie Publié sur le Web 04 March 2015.
Glycine has been used to reduce oxidative stress and pro-inflammatory mediators in some metabolic disorders; however, its effect on the vasculature has been poorly studied. The aim of this work was to explore the effect of glycine on endothelial dysfunction in aged rats. Aortic rings with intact or denuded endothelium were obtained from untreated or glycine-treated male Sprague-Dawley rats at 5 and 15 months of age. Concentration-response curves to phenylephrine (PHE) were obtained from aortic rings incubated with L-NAME, SOD, indomethacin, SC-560 and NS-398. Aortic mRNA expression of eNOS, NOX-4, COX-1, COX-2, TNF-α and IL-1β was measured by real time RT-PCR. The endothelial modulation of the contraction by PHE was decreased in aortic rings from aged rats. Glycine treatment improved this modulator effect and increased relaxation to ACh. Glycine augmented the sensitivity for PHE in presence of L-NAME and SOD. It also reduced the contraction by incubation with indomethacin, SC-560 and NS-398.
Glycine increased the mRNA expression of eNOS and decreased the expression of COX-2 and TNF-α. Glycine improved the endothelium function in aged rats possibly by enhancing eNOS expression and reducing the role of superoxide anion and contractile prostanoids that increases the NO bioavailability.