The Feasibility Of Anterior Urethral Reconstruction With Autologous Gallbladder Mucosal Graft:An Animal Experiment

The complex anterior urethral strictures are usually caused by idiopathic,trauma,inflammation therefore its treatment remains one of the biggest challenges in reconstructive urology.Through urethral dilation,or urethrotomy under direct invision or the urethrectomy of the fibrosis segment and anastomosis of the resident urethra,short urethral stricture can be cured.For long stricture(>2.5cm),or those in a distal location along the penile shaft,urethroplasty incorporating a graft or flap was usually required to augment the stenotic segment.There are two kinds of material currently being used which includes mainly the autologous materials and the tissue-engineered materials.Urological tissue engineering that does little harm to patients is emerging rapidly in recent years.However the vital factors such as complex process and high costs,limit the application of urological tissue engineering.Autologous materials,such as extragenital skin flaps,oral mucosa and colonic mucosa,as a practicable option have been applied for many years to repair the urethra on clinic.But,there are many complications accompanying the donor site,such as limitation of mouth opening,oral infection and ulceration,numb and pain.Moreover,the long and complex anterior urethral strictures need more grafts and may recur sometimes.Thus,for the those patients who have difficulty providing enough autologous grafts for themselves or who need second urethroplasty,seeking substantial autologous graft resources is imperative.Objective: To study the feasibility of autologous gallbladder mucosal graft in the reconstruction of anterior urethral defects in rabbits.Methods: A total of twenty-five male rabbits were divided into five groups: normal,2w,4w,8w and 24 w groups(each group,n=5).A ventral urethral mucosal defect(2.0 × 0.8 cm)was created and substitution urethroplasty was performed with autologous gallbladder mucosal graft in experimental groups(2w,4w,8w and 24 w groups).Retrograde urethrography,macroscopy study and histologic analysis were performed to evaluate the outcomes of urethroplasty.Result: Successful urethroplasty results were found with no evidence of complications.In 24 w group,retrograde urethrogram showed no stricture and macroscopy study showed the graft was well incorporated into normal urethral wall.On histological examination,the gallbladder epithelium was detected in 2w,4w and 8w group,whereas in 24 w group,a stratified epithelial layer on the graft which was almost indistinguishable from the normal urethra.Conclusion: Autologous gallbladder mucosal graft can survive in urine and is a potentially excellent material for anterior urethral reconstruction in rabbits.