LAUSR

BACKGROUND The imbalance of vasoconstrictor and vasodilator axes of the renin-angiotensin system (RAS) is observed in hypertension. Exercise regulates RAS level and improves vascular function. This study focused on the contribution of RAS axes in vascular function of mesenteric arteries and exercise-induced DNA methylation of the Agtr1a (AT1aR) and Mas1 (MasR) genes in hypertension. METHODS Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats were randomized into exercise or sedentary group. Levels of plasma RAS components, vascular tone, and DNA methylation markers were measured. RESULTS Blood pressure of SHR was markedly reduced after 12 weeks of aerobic exercise. RAS peptides in plasma were all increased with an imbalanced upregulation of Ang II and Ang-(1-7) in SHR, exercise revised the level of RAS and increased Ang-(1-7)/Ang II. The vasoconstriction response induced by Ang II was mainly via type 1 receptors (AT1R), while this contraction was inhibited by Mas receptor (MasR). mRNA and protein of AT1R and MasR were both upregulated in SHR, whereas exercise significantly suppressed this imbalanced increase and increased MasR/AT1R ratio. Exercise hypermethylated Agtr1a and Mas1 genes, associating with increased DNMT1 and DNMT3b and SAM/SAH. CONCLUSIONS Aerobic exercise ameliorates vascular function via hypermethylation of the Agtr1a and Mas1 genes and restores the vasoconstrictor and vasodilator axes balance.