Effect of Tadalafil on Prevention of Urethral Stricture After Urethral Injury: An Experimental Study

Abstract

OBJECTIVE To evaluate the preventive effect of phosphodiesterase type 5 inhibitor (tadalafil) on the formation of urethral stricture after urethral injury. MATERIALS AND METHODS A total of 28, 4-month-old male New Zealand rabbits were included and divided into 3 groups. Group 1 was a sham group with 8 rabbits that underwent only urethroscopy. Group 2 was a nontreatment group with 10 rabbits that underwent urethral electrocoagulation without any treatment. Group 3 was the treatment group with 10 rabbits that underwent urethral electrocoagulation with systemic tadalafil treatment. After 30 days of follow-up, urethroscopy and retrograde urethrography were performed to evaluate the morphological changes in the urethra. The urethra tissues were examined with standard light microscopy by a histologist, and apoptosis was evaluated by the terminal dUTP nick end-labeling assay. RESULTS Urethral diameters in group 1, group 2, and group 3 were 9.14 +/- 0.73 mm, 3.52 +/- 1.2 mm, and 7.68 +/- 1.14 mm, respectively. The differences in urethral diameters were statistically significant between groups (P < .01). Collagen deposition in submucosal connective tissue was significantly less in the tadalafil group vs the nontreatment group. The numbers of apoptotic cells in submucosal connective tissue were also quantitatively higher in urethral stricture groups compared to the sham group. CONCLUSION Tadalafil treatment had a protective effect against the formation of urethral stricture in rabbit model. This treatment can be a promising opportunity for urethral stricture and must be supported by clinical studies. (C) 2016 Elsevier Inc.