Evaluation of animal models for urethral stricture: a systematic review

Male urethral strictures are relatively common but can be challenging to treat. Varying urethroplasty surgery techniques and the use of different grafts show mixed outcomes. Many animal models have been used to study urethral stricture disease. The aim of this article is to review current animal models for urethral strictures as described in the contemporary literature. A systematic literature search was conducted in the PubMed and Web of Science databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search included all original and review articles published in English over the past three decades, up to January 2025. Keywords used were: “urethral stricture,” “animal model,” “urethral disease,” “preclinical studies,” “rat,” “mice,” “rabbit,” “pig,” “swine” and their combinations. Rat, rabbit, and pig animal models have been widely used for the creation of urethral strictures. Methods to create urethral strictures in rodents include mostly the use of TGF-β1 and electrocoagulation. Several additional methods have been used in rabbits, including endoscopic resection, radiofrequency coagulation, holmium laser and injection of bleomycin. In the porcine model, electro- and thermocoagulation have been used. Each method used for the creation of urethral strictures has its own set of advantages and limitations. Since the human penis has a unique anatomy, no animal model can fully simulate clinical urethral stricture disease. However, despite each model’s limitations, sufficient options are available to address most clinical research questions. Model selection should depend on the specific research goals and anatomical or technical requirements.