生物可降解性尿道内支架修复战伤性尿道狭窄的研究

目的建立战伤性尿道狭窄动物模型,探讨生物可降解性尿道内支架对其进行重建修复的可行性。方法将新西兰雄兔28只分为两组,实验组(n=20):以定位爆炸法建立尿道狭窄模型。一月后行逆行尿道造影、尿道镜检查,并切除狭窄段尿道,行病理组织学观察证实。后置入人工合成生物可降解尿道内支架,置入术后2、4、8、12周分别行逆行尿道造影、尿道镜检查以及尿流动力学检测。并在以上各时间点处死5只动物,取狭窄处尿道组织,观察组织学修复重建情况。对照组(n=8):于实验组爆炸处理后4周和支架置入12周,分别取对照组4只动物与实验组对比观察。结果实验组所有动物爆炸后4周在尿道球部狭窄形成稳定狭窄模型(狭窄段长5～10 mm,尿道腔缩窄50%以上)。尿道内支架置入后2周,组织学观察见黏膜上皮新生迹象,并有炎性细胞浸润;4周时上皮新生明显,炎性细胞消失;8周时出现尿道平滑肌细胞再生,12周时见损伤后尿道组织结构完全修复,与正常尿道组织比较差异无统计学意义(P>0.05)。。同时间点尿道镜检查证实尿道腔隙、黏膜形态结构无异于正常对照组。尿流动力学检测显示两组间差异无统计学意义(P>0.05)。。结论应用成功建立的战伤性尿道狭窄动物模型,证实生物可降解性尿道内支架能作为修复战伤性尿道狭窄的理想材料,具有损伤小,易操作,功能恢复快的特点。

Urethral stricture of battle wound repair with biodegradable stents

Objective To develop an experimental model of war-injured urethral stricture and e-valuate its reconstruction using a biodegradable stents in the rabbits. Methods Twenty-eight New Zealand male rabbits were randomly divided into study group (20) and control group ( 8 ) . In study group, bulbar urethra of the rabbits was bombed with a special instrument to develop the model of war-injured urethral stricture. One month later,each animal was assessed for urethra! stricture by videourethroscopy,retrograde urethrography, and resecting the part of the stricture urethra for histomorphological examination. Then, the biodegradable stents from polylactic acid were placed and inosculated with the normal part of the urethra. Five animals were killed for evaluating the reconstruction condition by histomorphological technique 2,4,8 and 12 weeks after operation respectively, and the 5 animals were assessed by videourethroscopy, retrograde urethrography and urodynamics 12 weeks after operation. The rabbits in contra! group underwent the same procedures as in study group 4 weeks after bombing and 12 weeks after the stents placed respectively. Results All animals in study group developed a significant bulbar stricture (the length of stricture 5-10 mm,reducing the limen by more than 50% ) 4 weeks after the bombing. Two weeks after operation,the regeneration of epithelial cells and the infiltration of inflammation cells were observed. The regeneration of epithelial cells was obvious and the infiltration of inflammation cells disappeared after 4 weeks postopera-tively. The smooth muscle cells were regenerated 8 weeks after operation,and 12 weeks later,the regenerated tissue was the the same as the normal urethra. The retrograde urethrography and urodynamics evaluation revealed that there was no difference between the two groups. Conclusion The biodegradable stents appears to be an ideal material for the reconstruction of war-injured urethral stricture.