Panax notoginseng saponins improve erectile function through attenuation of oxidative stress, restoration of Akt activity and protection of endothelial and smooth muscle cells in diabetic rats with erectile dysfunction.

Panax notoginseng saponins (PNS), which have an antioxidant property, are a widely used traditional Chinese medicine. In this study we investigated whether PNS can improve erectile function in rats with erectile dysfunction and the underlying mechanism by using a rat diabetic erectile dysfunction model. The rats were randomly divided into four groups: three PNS-treated groups (50, 100 and 150 mg/kg) and one saline-treated control group. Four weeks post treatment, electrostimulation was applied to the cavernous nerve and intracavernous pressure was measured to assess erectile function. Malondialdehyde, superoxide dismutase and glutathione were detected in the penises of all rats. Ultrastructural changes in the penises were examined by electron microscopy. Expression of Akt was detected by immunohistochemistry. The results showed that intracavernous pressure was increased in PNS-treated groups (100 and 150 mg/kg) compared to the control group. The levels of superoxide dismutase, glutathione and Akt were increased (p < 0.05) while that of malondialdehyde was decreased in the PNS groups. Ruptured endothelium, impaired smooth muscle cells and thrombus in the penises were detected by electron microscopy in the control group, but not in the PNS groups (10 and 150 mg/kg). The results suggest that PNS improves erectile function in diabetic rats. This improvement was associated with increased Akt expression, suppressed oxidative stress and restored functions of endothelial cells and smooth muscle cells in the penis.