Abstract: OBJECTIVE: To evaluate the effects of a combination of Yinyanghuo(Herba Epimedii Brevicornus)(HEB) and Cheqianzi(Semen Plantaginis)(SP) on erectile dysfunction caused by essential hypertension in spontaneously hypertensive rats(SHRs), and to elucidate the role of the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor(ACE2/Ang [1-7]/Mas receptor) axis in this process.METHODS: A total of 24 SHRs were randomly assigned to three groups: SHR-control, low-dose(12.5 g/kg) and high-dose(25 g/kg) HEB+SP(HEBSP). Eight Wistar-Kyoto rats were used as normal controls. HEBSP was administered by oral gavage for 28 d. Erectile function was measured once a week using the Heaton test. After 4 weeks of treatment, the corpus cavernosum was harvested from each rat to measure nitric oxide(NO), nitric oxide synthase(e NOS) and Ang(1-7) levels, as well as ACE2, Mas receptor and neuronal nitric oxide synthase(n NOS) protein expression.RESULTS: After 4 weeks of treatment, HEBSP significantly increased erectile function in the treated group compared with SHR-control group(P < 0.01).Additionally, HEBSP treatment significantly increased cavernosal levels of Ang(1-7), e NOS and NO. Moreover, HEBSP significantly elevated the expression levels of ACE2, Mas receptor and n NOS.These beneficial effects were elevated in the high-dose HEBSP group.CONCLUSION: HEBSP improved erectile function in SHRs by upregulating the ACE2/Ang(1-7)/Mas receptor axis, e NOS and n NOS pathways.

Key words: Rats,Inbred SHR, Peptidyl-Dipeptidase A, Angiotensins, Nitric oxide synthase, Corpus cavernosum, Yinyanghuo(Herba Epimedii Brevicornus), Cheqianzi(Semen Plantaginis)