[Preventive and therapeutic effects of Icariside Ⅱ on radiation injury-induced erectile dysfunction in rats]

To explore the preventive and therapeutic effects of Icariside Ⅱ (ICAⅡ) on radiation injury-induced ED (Ri-ED) in rats.

Twenty-four 10-week-old male SD rats received exposure of the prostate to single X-ray irradiation of 20 Gy, and were randomly equally divided into an Ri-ED group (6 survived and 6 died) and a treatment group treated with ICAⅡ at 4.5 mg/kg/d (9 survived and 3 died). Another 6 SD rats were taken as negative controls. After 4 weeks of continuous intragastric administration and 2 weeks of drug elution, the erectile function of the rats was evaluated by measurement of the maximum intracavernous pressure / mean arterial pressure (ICPmax/MAP), and the penile tissues were subjected to immunofluorescence staining, immunohistochemistry, Masson's trichrome staining, Western blot and detection of oxidative stress indicators.

Compared with the negative controls, the rats in the Ri-ED group showed significant decreases in ICPmax/MAP (0.76 ± 0.09 vs 0.42 ± 0.06, P < 0.01), the number of nNOS-positive nerve fibers in the corpus cavernosum (10.17 ± 2.64 vs 3.17 ± 1.72, P < 0.01), the content of endothelial cells (1.39 ± 0.30 vs 0.35 ± 0.12, P < 0.01), the expressions of nNOS (0.42 ± 0.08 vs 0.08 ± 0.01, P < 0.01) and eNOS (0.99 ± 0.24 vs 0.12 ± 0.08, P < 0.01) and the activity of superoxide dismutase (SOD) (［343.73 ± 58.57］ vs ［153.50 ± 34.06］ U/mg prot, P < 0.01), but an increase in the malondialdehyde (MDA) level (［1.80 ± 0.31］ vs ［3.25 ± 0.21］ nmol/mg prot, P < 0.01). In comparison with the Ri-ED group, the animals treated with ICAⅡ exhibited remarkably increased ICP/MAP (0.42 ± 0.06 vs 0.66 ± 0.07, P < 0.01), number of nNOS-positive nerve fibers (3.17 ± 1.72 vs 7.33 ± 1.75, P < 0.05), content of endothelial cells (0.35 ± 0.12 vs 1.07 ± 0.36, P < 0.01), and expressions of nNOS (0.08 ± 0.01 vs 0.16 ± 0.05, P < 0.05) and eNOS (0.12 ± 0.08 vs 0.86 ± 0.30, P < 0.01) in the corpus cavernosum, but a decreased level of MDA (［3.25 ± 0.21］ vs ［2.17 ± 0.55］ nmol/mg prot, P < 0.05). In addition, ICAⅡ effectively reduced radiation injury-induced mortality of the rats.

IcarisideⅡ can significantly improve ED and pathological changes and reduce mortality caused by radiation injury in rats, which may be related to its ability of improving radiation-induced oxidative stress.