Evaluation of bi-layer silk fibroin grafts for onlay urethroplasty in a rabbit model of urethral stricture disease

<b>Background:</b> Autologous tissues such as buccal mucosa (BM) are widely used for reconstruction of urethral strictures; however, limitations such as donor site morbidity and scarce tissue supply require the development of alternative biomaterials for urethral repair. The goals of this study were to determine the safety and efficacy of bi-layer silk fibroin (BLSF) matrices for urethral stricture repair and compare histological and functional outcomes to the standard approach, BM urethroplasty under good laboratory practices.<b>Material and methods:</b> A total of 13 rabbits exhibiting urethral stricture formation following electrocoagulation injury were treated with onlay urethroplasty with either acellular BLSF (N = 7) or autologous BM (N = 6) grafts for 3 months. Uninjured control rabbits were maintained in parallel (N = 4).<b>Results and conclusion:</b> Animals receiving BLSF implants were demonstrated to be functionally equivalent to BM grafts in their ability to restored strictured calibers, support micturition and promote tissue regeneration with minimal inflammation.