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

PURPOSE: 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.