Peritoneal cavity as bioreactor to grow autologous tubular urethral grafts in a rabbit model.

Objective: To investigate whether peritoneal cavity could function as bioreactor to produce autologous tubular grafts for urethral reconstruction in male rabbits.

Methods: 8Fr silastic tubes were implanted into peritoneal cavities of nine male rabbits. By 2 weeks, tubes were harvested and the tubular tissue covering the tubes was everted. A pendulous urethral segment of 1.5 cm long was totally excised and urethroplasty was performed with the everted tubular tissue in an end-to-end fashion. Another nine male rabbits underwent the same urethral resection and re-anastomosis as controls. Urethrography was performed at 1, 2 and 6 months postoperatively. Meanwhile, the neo-urethra were harvested and analyzed grossly and histologically.

Results: Histological analysis of the tubular tissue demonstrated transversely arranged myofibroblasts embedded in homogeneous collagen bundles and an outer layer of mesothelium. The tissue was easily everted and successfully transplanted as a urethral graft. Serial urethrography indicated no stricture or diverticula formation. While all animals of the control group developed stricture. Histological analysis of the neo-urethra demonstrated normal urethral architecture by 1 month, composed of multi-layers of urothelium surrounded by smooth muscle bundles, which became increasingly organized with time. By 6 months, the neo-urethra could be hardly distinguished from native urethra both grossly and histologically.

Conclusions: These results show that the autologous tissue grown within the recipients' peritoneal cavity can be used successfully for tubularized urethral reconstruction in male rabbits.