Impact of Hypogonadism on Urethral Stricture Formation: Insights from Rabbit Model with Ultrasound

This study investigates the impact of hypogonadism on urethral stricture formation in a rabbit model, aiming to improve the efficacy of stricture induction and reduce the need for multiple inductions. Urethral strictures are traditionally studied through animal models, where male rabbits undergo endoscopic urethral mucosa electroresection. However, the success rate of stricture formation after a single procedure is low, often requiring repeated inductions, which increases stress, time, and expense. In human studies, hypogonadism has been linked to more severe urethral strictures. Based on this, researchers hypothesized that inducing a hypogonadal state in rabbits could enhance the success and severity of stricture formation after mucosal trauma. Ten adult male New Zealand rabbits were divided into a control group and a treatment group, with the latter undergoing bilateral orchiectomy to induce hypogonadism. After two months, all rabbits underwent a urethral stricture induction procedure. Six weeks later, evaluations through retrograde urethrogram (RUG) and cystoscopy assessed the extent of stricture formation. Findings showed that all castrated rabbits (100%) developed significant strictures, with an average lumen reduction of 55%, compared to only 40% in the control group, which had an average reduction of 27%. Notably, severe strictures (over 50% lumen stenosis) were observed in 60% of the castrated group, while none occurred in the control group. Additionally, cystoscopy revealed that 90% of rabbits in the hypogonadal group developed severe strictures that prevented scope passage. The study concludes that hypogonadism, induced through castration, significantly increases both the likelihood and severity of urethral stricture formation in this animal model. Future research will examine the histological changes to better understand the mechanisms behind these findings.