OBJECTIVETo evaluate the feasibility of reconstruction of rabbit urethra using urethral extracellular matrix.

METHODSExtracellular matrix was obtained from the urethra of 20 donor New Zealand rabbits. In experimental group, 20 rabbits underwent segmental urethral resection (about 1.0 to 1.5 cm in length) and the defects were replaced by a tube of extracellular matrix. The serum TNFalpha was detected by ELISA to assess the immunity response preoperatively and 12, 24, 48 h postoperatively. The regenerated urethral segments were taken for histologic and pathologic study 10 days, 3 weeks, 6 weeks and 24 weeks after operation. The urodynamics, urethroscopy and urethrography were also performed.

RESULTSThe serum TNFalpha in experiment group slightly rised, with no significant difference when compared with that in control group. 10 days after operation, epithelial cell migrated into the extracellular matrix from two ends, and small vessels were also found. 3 weeks later, several layers of urothelium covered the whole surface of the matrix tube. 6 weeks later, the irregularly arranged smooth muscle fibers were fist observed by Van Gieson staining. 24 weeks after operation, the smooth muscle cells increased, the appearance of the regenerated urethra segments were very similar to normal urethral wall components. The urethrography and urodynamic evaluation revealed no difference between the normal and the regenerated urethral tube.

CONCLUSIONSThe urethral extracellular matrix might be an ideal replacement material for urethral defect.