Histological and Biochemical Evaluation of Urethral Scar following Three Different Hypospadias Repairs: An Experimental Study in Rabbits.

Introduction:  Several urethroplasties have been employed in the surgical treatment of hypospadias. Neourethral strictures are among the most common postoperative complications that often require reoperation.

Materials And Methods:  We created a hypospadias model in New Zealand white male rabbits through a hypospadias-like defect and acute repair. A total of 24 animals were randomly allocated into three groups: tubularized incised-plate urethroplasty (TIPU) group (8), perimeatal-based flap urethroplasty (Mathieu) group (8), onlay island flap urethroplasty (onlay) group (8), and corresponding surgical procedures were immediately performed to reconstruct neourethra. The rabbits were killed postoperatively at 5 days, 2 weeks, 6 weeks, and 3 months, respectively. The penile tissue was harvested for histological and biochemical investigations to evaluate the expressions of transforming growth factor β1 (TGF-β1) and α-smooth muscle actin (α-SMactin) in all groups.

Results:  All rabbits were operated on uneventfully. The amount of collagen content was increased in the Mathieu and onlay groups than in the TIPU group ( < 0.05). Biochemical analysis showed that the expression of TGF-β1 in the TIPU group was decreased compared with the two other groups at 2 or 6 weeks postoperatively ( < 0.01). The expression pattern regarding α-SMactin was similar at 6 weeks or 3 months postoperatively ( < 0.01).

Conclusion:  The neourethra repaired by TIPU was practically resumed to normal anatomy and scarring was less apparent than the two other groups. Therefore, TIPU is considered as a relatively rational approach for hypospadias repair. The activity of fibroblasts has been increased in the long term, which may be the pathogenesis of neourethral stricture following hypospadias repair.