[Icariin improves erectile function in spontaneously hypertensive rats by up-regulating Nrf2]

To investigate whether icariin improves erectile function in spontaneously hypertensive rats (SHR) by regulating the NRF2 pathway.

We equally randomized 24 ten-week-old healthy male Wistar-Kyoto rats (WKR) and healthy male SHR rats into four groups: WKR control, WKR + icariin, SHR control and SHR + icariin, the controls treated intragastrically with normal saline, and the animals in the WKR + icariin and SHR + icariin groups with icariin, all at 10 mg/kg/d for 4 weeks. Then we obtained the body weight and serum T level of the rats and measured the maximum intracorporeal pressure / mean arterial pressure (ICPmax/MAP) and the contents of nuclear factor-erythroid 2-related factor-2 (Nrf2), memeoxygenase-1 (HO-1), endothellial nitric oxide synthase (eNOS), peroxisome proliferator activated receptor gamma (PPAR-γ) , dimethylarginine dimethylaminohydrolase (DDAH), nitric oxide (NO), cyclic guanosine monophosphate (cGMP) and asymmetric dimethylarginine (ADMA) in the corpora cavernosa tissue.

There were no statistically significant differences in the body weight or serum T level among the four groups of rats. The ratios of ICPmax/MAP and P-eNOS/eNOS and the expressions of Nrf2, HO-1, PPAR-γ, DDAH, NO and cGMP in the corpora cavernosa tissue were significantly higher in the SHR + icariin group than in the SHR control (P < 0.05) but lower than in the WKR control. The ADMA level in the corpora cavernosa tissue was remarkably reduced in the SHR + icariin group compared with that in the SHR control (P < 0.05).

By up-regulating the expression of Nrf2, icariin increases the HO-1, DDAH and PPAR-γ levels and the P-eNOS/eNOS ratio in the corpora cavernosa and improves the erectile function of spontaneously hypertensive rats.