Development and characterization of urethral stricture model in rabbits

Abstract

Objective To establish an experimental model of urethral stricture in rabbits. Methods A total of 21 adult male New Zealand rabbits were included into group. After intravenous anesthesia, urethroscopy was performed with a pediatric resectoscope (F13). Fifteen animals were randomly selected as the study group. A 1cm-long circumferential electrocoagulation of the bulbar urethra was performed to these animals until ulceration of the mucosa. The remaining 6 animals underwent video urethroscopy without electrocoagulation, serving as controls. On the 30th day, retrograde urethrogram and urethroscopy were performed to evaluate urethral stricture formation, histological examinations (HE and Sirius Red staining) were done to assess urethral pathological change. Results Two rabbits in study group died and no death occurred in controls. Based on urethrogram and urethroscopy, no rabbits in control group developed urethral stricture, while significant stricture formation was observed in every case of the study group. Histological examination showed a normal urethra in control cases, while at stricture site of the study group extensive fibrosis of muscle and submucous tissue was observed with a large number of fibroblasts infiltration. High collagen expression in fibrosis tissue was assayed by Sirius Red staining. Conclusion A 1cm-long endoscopic electrocoagulation can successfully induce urethral stricture formation in rabbit models. This method offers an ideal animal model for the fundamental and clinical study of urethral stricture.