A1222 Exercise training enhances baroreflex and depressor via activation of central ACE2-Ang(1–7)-Mas axis in SHR

Abstract

Objectives: To investigate the effects of exercise training on the development and progression of hypertension, blood pressure regulation and the gene and protein expression of angiotensin converting enzyme 2 (ACE2) and MAS receptors in the paraventricular nucleus (PVN). Methods: Male 6 weeks of old spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats were randomly assigned to the sedentary (Sed) or the exercise training (ExT) group. Exercise training was performed on a treadmill for 20 weeks (18–20 m/min, 60 min/d, 5d/wk). Blood pressure, baroreflex sensitivity (BRS) and the mRNA and protein expression of ACE2 and Mas receptors in the PVN were determined. Alterations of BRS were evaluated before and after intracerebroventricular (ICV) injection of angiotensin1–7 (Ang1–7) and its antagonist A779, respectively. Results: BP was over 140mmHg in the 8th wk of SHR + Sed, but exercise training postponed 2 weeks of the development of hypertension and retarded hypertension progression in SHR. Also, exercise training prevented the decrease in BRS in the SHR + ExT compared with SHR + Sed (P < 0.01). ICV injection of A779 inhibited the BRS in SHR + ExT, which abolished the benefits of exercise training (P < 0.01), but had no influence in SHR + Sed. In contrast, angiotensin1–7 enhanced BRS in sedentary and trained SHR (P < 0.05). Exercise training up-regulated the mRNA and protein expression of ACE2 and Mas receptors in the PVN in SHR, buy not in WKY (P < 0.01). Conclusion: Early exercise training postpones the progression of prehypertension and improves blood pressure regulation, which is associated with the enhanced function of central ACE2-Ang (1–7)-Mas axis. (Support by the National Natural Science Foundation of China (No.81372111) and the Natural Science Foundation of Fujian Province (No.2014 J01339)