Effects of chronic vardenafil treatment persist after end of treatment in rats with acute arteriogenic erectile dysfunction.

INTRODUCTION: In our previous study, chronic vardenafil treatment improved erectile function soon after the end of the treatment in rats with acute arteriogenic erectile dysfunction (ED). AIM: The aim of this study is to evaluate whether the effects of chronic vardenafil treatment persist after the end of treatment using rats with acute arteriogenic ED. METHODS: Rats were randomly divided into three groups: (i) control; (ii) ligation; and (iii) vardenafil + no treatment. Rats in the ligation and vardenafil + no treatment groups underwent ligature of the bilateral internal iliac arteries to induce acute arteriogenic ED and were subsequently treated with vehicle or vardenafil (4.0 mg/kg/day), respectively, for 3 weeks. Subsequently, all rats were kept for a further 2 weeks with no treatment. Rats in the control group underwent sham surgery. MAIN OUTCOME MEASURES: Erectile function was assessed by changes in intracavernous pressure (ICP). Smooth muscle (SM)/collagen ratios in corpus cavernosum were analyzed by Masson trichrome staining. Transforming growth factor-ß1 (TGF-ß1 ) mRNA and protein levels in corpus cavernosum (CC) were, respectively, evaluated by real-time polymerase chain reaction (PCR) analysis and Western blotting analysis. RESULTS: ICP/mean arterial pressure (MAP) in the ligation group remained significantly lower than that in control group (P < 0.01). Despite no treatment for 2 weeks, ICP/MAP in the var + no treatment group remained significantly higher than that in ligation group (P < 0.05). SM/collagen ratio in the ligation group remained significantly lower when compared with the control group (P < 0.01). The ratio in the var + no treatment group remained significantly higher when compared with the ligation group at 2 weeks after the end of treatment (P < 0.05). TGF-ß(1) mRNA and protein levels did not differ among the groups. CONCLUSIONS: The effects of chronic vardenafil treatment on erectile function and penile structure persist, even after the end of treatment, in acute arteriogenic ED rats.

Chronic vardenafil treatment improves erectile function via structural maintenance of penile corpora cavernosa in rats with acute arteriogenic erectile dysfunction.

INTRODUCTION: Chronic phosphodiesterase type 5 inhibitor treatment may be useful in reversing erectile dysfunction (ED). However, the mechanisms of this improvement remain unknown. AIM: The aim of this article was to determine the mechanisms of the improvement by chronic vardenafil treatment for acute arteriogenic ED in rats. METHODS: Eight-week-old male Wistar-ST rats were divided into four groups: sham-operated rats (Control group) and rats with acute arteriogenic ED induced by ligating bilateral internal iliac arteries (Ligation group), subsequently treated with low-dose (0.4 mg/kg/day; VL group) or high-dose (4.0 mg/kg/day; VH group) vardenafil for 20 days from 1 week after ligature. MAIN OUTCOME MEASURES: Erectile function was assessed based on changes of intracavernous pressure (ICP) followed by electrostimulation of the cavernous nerves and was evaluated by the area under the curve of ICP/area under the curve of mean arterial pressure (area of ICP/MAP). Transforming growth factor (TGF)-ß(1), vascular endothelial growth factor-A, endothelial nitric oxide synthase (eNOS), inducible NOS, and neuronal NOS mRNA expression levels in penile corpus cavernosum were determined by real-time PCR. Western blotting for TGF-ß(1) protein levels and Masson trichrome staining of penile tissues were performed in each at group 4 weeks after surgery. RESULTS: In the VH group, area of ICP/MAP was significantly improved when compared with the Ligation group (P < 0.01). The smooth muscle (SM)/collagen ratio in the VH group was significantly higher than in the Ligation group (P < 0.05), and was comparable with that in the Control group. TGF-ß(1) mRNA and protein levels in the VH group were significantly lower when compared with the Ligation group (P < 0.05). CONCLUSIONS: Chronic vardenafil administration ameliorates impairment of penile hemodynamics and maintains normal SM to collagen ratio in cavernous tissues after acute arterial injury in rats.