Comparison of two experimental models for urethral stricture in the anterior urethra of the male rabbit.

OBJECTIVE To compare 2 urethral stricture models and determine the appropriate model for the generation of urethral stricture in rabbits. METHODS A total of 28 adult male New Zealand rabbits were included in the present study. They were separated randomly into 3 groups. Urethroscopy was performed using a pediatric resectoscope (13F). In 1 group (10 rabbits), circumferential electrocoagulation of the anterior urethra 2-3 mm long was performed until ulceration of the mucosa occurred. In the second group (10 rabbits), 2-3 mm wide resection from the anterior urethra was performed that was deep enough to expose the periurethral tissue to allow urine leakage from the lumen. The remaining 8 rabbits as the control group underwent only urethroscopy. On the 30th day, retrograde urethrography and urethroscopy were performed to evaluate urethral stricture formation. Histologic examination was done to evaluate the urethral pathologic changes. RESULTS According to the urethrography and urethroscopy findings, no rabbits in the electrocoagulation or control group developed urethral stricture; however, significant stricture formation was observed in every case of the electroresection group. Regenerating urothelium at the luminal side of the urethra was seen in 6 rabbits in the electrocoagulation group and 4 showed normal urethra. In the electroresection group, extensive fibrosis that obstructed the urethral lumen and nodular collagen bundles in the urethral wall were seen. CONCLUSION The electroresection method is more reliable than the electrocoagulation method in developing urethral stricture in the rabbit model. A 2-3-mm-wide resection from the anterior urethra can successfully generate urethral stricture with respect to electrocoagulation. Electroresection offers an ideal animal model for generating urethral stricture.