Objective: To explore the preventive and therapeutic effects of Icariside Ⅱ (ICAⅡ) on radiation injury-induced ED (Ri-ED) in rats.
Methods: 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.
Results: 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.
Conclusion: 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.
Keywords: icariside Ⅱ; radiation injury; erectile dysfunction; oxidative stress; rat.