Early administration of phosphodiesterase 5 inhibitors after induction of diabetes in a rat model may prevent erectile dysfunction.

BACKGROUND: The possible role of phosphodiesterase 5 inhibitors (PDE5Is) in prevention of negative effect of diabetes mellitus (DM) on erectile function is not well settled. OBJECTIVES: To investigate the effect of early administration of vardenafil on erectile function, cavernosal structure, and genes expression in a rat model of DM. MATERIALS AND METHODS: This experimental study was carried out at Suez Canal University's research laboratory. This study was conducted on a total of 60 adult male Albino Wistar rats, aged 60-80 days and weighing an average of 200 g. Rats were equally divided into six groups of 10 rats each: Group I (sham); Group II (DM with no treatment); Groups III, IV, V, and VI received vardenafil started at day 1, week 4, week 8, and week 12 after induction of DM, respectively. Functional study assessment of all groups was performed before euthanization, and then tissues were harvested for histopathological, ultrastructural, and molecular examinations. RESULTS: There was a significant difference of intracavernosal pressure between early (94 ± 2.18) and late (40.5 ± 1.94) treatment groups (p = 0.011). Histopathological and ultrastructural changes of DM with no treatment and late treatment groups showed distorted cavernous architecture and extensive fibrosis. There was significant difference of smooth muscle to collagen ratio between early and late treatment groups (p = 0.035). There was significant upregulation of nNOS(p = 0.021) and iNOS (p = 0.047) in early vs. late treatment group. The difference was insignificant in eNOS (p = 0.386) or TGF-ß1(p = 0.149). DISCUSSION AND CONCLUSION: Early treated rats with vardenafil had preserved erection and normal cavernosal structure, ultrastructure and gene expression of iNOS, nNOS, eNOS, and TGF-ß1. Quantification of gene expression would improve our knowledge regarding cytokines expression and molecular background of DM-associated ED. Clinical application of this result may encourage early administration of PDE5I to prevent deleterious effects of DM on erectile function in newly diagnosed DM patients with probable uncontrolled blood glucose.

Changes in erectile organ structure and function in a rat model of chronic prostatitis/chronic pelvic pain syndrome.

There is a growing recognition of the association between chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and erectile dysfunction (ED); however, most of the reports are based on questionnaires which cannot distinguish between organic and functional ED. The purpose of this study was to determine the exact relationship between CP/CPPS and ED, and to investigate the changes in erectile organ structure and function in a rat model of CP/CPPS. We established a rat model of experimental autoimmune prostatitis (EAP), which is a valid model for CP/CPPS. Erectile function in EAP and normal rats was comparable after cavernous nerve electrostimulation. The serum testosterone and oestradiol levels, ultrastructure of the corpus cavernosum and expression of endothelial nitric oxide synthase and neuronal nitric oxide synthase in the two groups were similar; however, there was a decrease in smooth muscle-to-collagen ratio and alpha-smooth muscle actin expression and an increase in transforming growth factor-beta 1 expression was observed in EAP rats. Thus, organic ED may not exist in EAP rats. We speculate that ED complained by patients with CP/CPPS may be psychological, which could be caused by impairment in the quality of life; however, further studies are needed to fully understand the potential mechanisms underlying the penile fibrosis in EAP rats.

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.