Exercise training attenuates hypertension progression via activation of central ACE2-Ang(1-7)-Mas axis in prehypertensive rats / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effects of exercise training on the progression from prehypertension to hy -pertension,blood pressure regulation and the angiotensin-converting enzyme 2(ACE2)-angiotensin(Ang)(1-7)-MAS axis activation in cardiovascular centers ,and to elucidate the central mechanisms of exercise training postponing hyperten -sion progression.METHODS:The male spontaneously hypertensive rats(SHR;n=20,5 weeks old)and normotensive Wistar Kyoto(WKY)rats(n=20)were randomly assigned to sedentary(Sed)group and exercise training(ExT)group. The trained rats run on a treadmill in moderate-intensity for 20 weeks.Systolic blood pressure(SBP)was measured by tail-cuff method.The baroreflex sensitivity(BRS)was assessed by intravenous injection of phenylephrine.The expression of ACE2 and MAS receptor at mRNA and protein levels in baroreflex centers were determined by real-time PCR and Western blot,respectively.Alterations of BRS were evaluated before and after intracerebroventricular injection of MAS receptor ago -nist Ang(1-7)and its antagonist A779,respectively.RESULTS:Compared with SHR +Sed group,exercise training since prehypertension significantly postponed the development of hypertension ,delayed the hypertension progression ,and decreased SBP in both SHR and WKY rats(P<0.05).Exercise training enhanced blood pressure regulation and improved the BRS in SHR(P<0.01).The expression of ACE2 and MAS receptor at mRNA and protein levels in the baroreflex cen-ters(rostral ventrolateral medulla ,nucleus tract solitarius and paraventricular nucleus )were up-regulated in SHR +ExT group(P<0.05).Central administration of A779 abolished the benefits of exercise-induced improvement of BRS in SHR +ExT group(P<0.01).In contrast,Ang(1-7)improved the BRS in both SHR +Sed group and SHR +ExT group(P<0.05).CONCLUSION:Exercise training postpones hypertension progression and improves blood pressure regula -tion,which may be associated with the activation of central ACE 2-Ang(1-7)-Mas axis.