Free ureteral replacement in rats: regeneration of ureteral wall components in the acellular matrix graft

Abstract

Objectives To evaluate ureteral replacement by a free homologous graft of acellular matrix in a rat model. Methods In 30 male Sprague-Dawley rats, a 0.3 to 0.8-cm midsegment of the left ureter was resected and replaced with an acellular matrix graft of equal length placed on a polyethylene stent. The animals were killed at varying intervals, and the grafted specimens were prepared for light and electron microscopy. Results In all animals, the acellular matrix graft remained in its original position without evidence of incrustation or infection, and histologic examination showed complete epithelialization and progressive infiltration by vessels. At 10 weeks, smooth muscle fibers were observed; at 12 weeks, nerve fibers were first detected; at 4 months, smooth muscle cells had assumed regular configuration. Conclusions The ureteral acellular matrix graft appears to promote the regeneration of all ureteral wall components.