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-β1 (TGF-β1 ) 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-β(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.