Repeated Transurethral Interventions Increase Elastin Degradation and Stricture Severity
Merlin Mamachan, Michael Witthaus, Jill Buckley, Mahadevan RajasekaranObjective:
To investigate the role of elastin in the progression of recurrent urethral strictures induced by repeated transurethral endoscopic interventions, using a preclinical animal model with translational relevance.
Methods:
Urethral strictures were induced in middle-aged male New Zealand White rabbits (
Results:
A retrograde urethrogram performed on day 14 post-injury revealed urethral stricture formation at the injury site, with further narrowing observed by day 45. In the electrocoagulation-only group, the urethral cross-sectional area decreased to approximately 5–10 mm 2 at the injury site (∼30%–50%), whereas in the electrocoagulation plus UD group, a further reduction, reaching approximately 3–8 mm 2 (∼60%–75%) relative to baseline, was observed. VVG-stained histological sections from the electrocoagulation-only group showed elastic fiber fragmentation, degradation, and irregular distribution, whereas the electrocoagulation plus UD group exhibited more severe elastic fiber fragmentation and a nonuniform distribution. The quantification of elastin fragmentation and elastin% showed higher mean values in the electrocoagulation plus UD group than in the electrocoagulation-only group, although the differences were not statistically significant. VVG staining of human urethral stricture tissues demonstrated extensive degradation of the elastic fiber network, and immunostaining revealed colocalized expression of collagen I and elastin.
Conclusion:
This study suggests that elastin degradation is associated with urethral fibrogenesis in recurrent stricture formation following repeated transurethral interventions.