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[Rabbit urethral defect repair with freeze-dried acellular bladder submucosa].

OBJECTIVE
To evaluate the result of urethral defect repair using freeze-dried acellular bladder submucosa.


METHODS
The freeze-dried acellular bladder submucosa was obtained from human cadaveric bladder submucosa using freeze-thawed enzymatic treatment and the freeze-drying technique. 18 male New Zealand rabbits were used in this experiment. A defect of 1.0 cm x 0.5 cm was created in the ventral urethra of the animal. The acellular matrix was grafted to the urethral defect in 14 rabbits. The other 4 animals underwent a sham operation as the controls. From postoperative one to twenty-four weeks, the animals underwent retrograde urethrography at certain intervals. The grafts of the acellular matrix were taken and prepared for histological evaluation.


RESULTS
No obvious urethral stricture was observed in the 14 matrix-grafted animals. Histological examinations of the specimens showed progressive infiltration of cells and vascular vessels. Complete epithelization was obtained at 2 weeks. The orientation of collagen fibers in the matrix-grafted area tended to be regular with time.


CONCLUSIONS
Freeze-dried acellular bladder submucosa may be a suitable material for urethral defect repair, which induces urethral mucous cells to migrate, grow and epithelialize.