Panax notoginseng saponins improve the erectile dysfunction in diabetic rats by protecting the endothelial function of the penile corpus cavernosum

Diabetes mellitus (DM)-associated ED is predominantly due to neurovascular dysfunction mediated by nitric oxide (NO) suppression. Panax notoginseng saponins (PNS) are widely used for treating cardiovascular disease in China. The aim of this study was to evaluate the effects of PNS on penile erection and corpus cavernosum tissues in rats with diabetes-associated ED. Four weeks after PNS treatment, erectile function was assessed by intracavernous pressure (ICP) and mean arterial pressure (MAP) measurements. The level of NO, cyclic guanosine monophosphate (cGMP) and advanced glycation end products (AGEs) in cavernous tissue were assessed. Immunohistochemical staining and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) were performed for detecting endothelial NO synthase (eNOS) and apoptosis, respectively. The results show that ICP/MAP ratio was significantly increased in high-dose (150 mg kg−1 per day) PNS-treated group compared with the diabetic ED untreated group (DM group). Compared with the untreated group, the expression of eNOS and the levels of NO and cGMP were increased in the PNS-treated groups. Moreover, apoptosis was markedly decreased in the group that received 150 mg kg−1 per day of PNS. These results suggest that PNS may be used for improving the ED in diabetic rats via the NO/cGMP pathway and restores the function of endothelium in corpus cavernosum.