小肠黏膜下层修复尿道的实验研究

STUDY ON SMALL INTESTINAL SUBMUCOSA AS REPAIR MATERIALS IN URETHRAL RECONSTRUCTION

目的探讨小肠黏膜下层(smallintestinalsubmucosa,SIS)在尿道修复重建中的应用价值。方法24只日本雄性大耳白兔,随机分为A、B、C及D组(n=6)。A、B组切除前尿道2.0cm,A组,用管状SIS修复尿道缺损;B组将其断端与周围组织直接缝合作为对照。C、D组仅切除2.0cm尿道前壁,保留一半尿道壁为底板,C组用片状SIS修复尿道缺损;D组将其残端与周围组织直接缝合作为对照。均于修复后6、12周行组织学观察;12周行尿道膀胱造影及尿动力学检查。结果术后6周,A、C组修复的尿道有单层上皮细胞覆盖,基层组织中可见SIS的微小碎片包裹,出现不规则紊乱的平滑肌细胞生长,A组较C组的炎性反应重,有白细胞及淋巴细胞浸润,C组出现新生血管。术后12周,C组的上皮组织及基层下组织与D组无明显差别,平滑肌排列规则,血管数目进一步增多,炎性反应消失,未见SIS组织;A组中仍可见少数SIS的微小碎片;B组1只、D组2只尿道自行修复,余可见尿道闭塞,大量结缔组织生长,炎性细胞浸润,无正常上皮结构。术后12周尿道膀胱造影,A、C组可见尿道完整、光滑,无尿液外渗、尿道憩室等形成;尿动力学检查示A、C组的膀胱容量、最大尿道压分别与术前比较,差异无统计学意义(P>0.05),而B、D组不能置入测压管检测。结论SIS可作为兔尿道修复重建的良好支架材料,片状SIS修复优于管状SIS修复。

Objective To explore the possibility of small intestinal submucosa （SIS） for reconstruction of urethral defect. Methods Twenty-four male rabbits were divided into 4 groups： group A （the tubulate SIS graft for urethral repair）, group B （control group, urethral tubulate defect）, group C （the SIS patch graft for urethral repairs）, group D （control group, urethral part defect）. Then the regenerative segment was studied with histological technique by hematoxylin-eosin straining and immunohistological straining for a-actin after 6 and 12 weeks postoperatively. The retrograde urethrography and urodynamics were used to evaluate the function of the regenerative urethra at 12 weeks after operation. Results In groups A and C, at 6 weeks after operation, the luminal surface of matrix was completely covered by urothelium, minimal SIS graft was observed in the extracellular matrix, new smooth-muscle cells was confirmed; however, more inflammatory cells were observed in the host-matrix anastomosis in group A than in group C. At 12 weeks postoperatively, the regenerative tissue was equivalent to the normal urethral tissue and SIS disappeared in group C, but some minimal SIS grafts were observed in group A. In groups B and D, urethral strictures and fibrous connective tissue were observed except 3 cases. The urethrography showed wide smooth urethral in group A and C, meawhile urodynamic evaluation didn＇t demonstrat significant difference （P〉 0. 05） in the bladder volume and the maximum urethral pressure between preoperation and postoperation in group A or group C. Conclusion SIS can be a useful material for urethral repair in rabbits, the SIS patch graft is superior to the tubulate SIS graft in urethra reconstruction.