丙交酯/乙交酯共聚材料支架的输尿管原位组织相容性

Ureteral in situ biocompatibility of L-lactide-glycolic acid copolymer 80∶20 stent

目的：探讨可生物降解材料丙交酯／乙交酯共聚物（PLGA80：20）支架的输尿管原位组织相容性。方法：16只雄性家犬左侧输尿管施以离断吻合术后随机分为2组：实验组（n=8）将PLGA支架植于输尿管吻合局部支撑引流，对照组（n=8）植入UROVISION支架，分别于术后2、4、8及12周取2只犬术侧输尿管行组织病理学切片检查，采用Lumiaho评分法进行组织学反应评价。结果：实验组PLGA材料在植入12周内完全降解，输尿管腔内无材料碎片残留；支架植入2～4周，术侧输尿管局部见移行上皮过度增生、固有层炎症细胞浸润；支架植入8～12周，随PLGA材料降解，术侧输尿管壁炎症消退，仅见极轻微的移行上皮增生。对照组早期病理表现与实验组相似，但局部炎症反应随植入时间延长而逐渐加重，术后12周时输尿管移行上皮增生、固有层炎细胞浸润及组织充血、水肿等反应比实验组明显（P〈0．05）。结论：PLGA材料支架植入犬输尿管后发生的输尿管炎症反应是可恢复的，PLGA材料具有很好的组织相容性，是加工可生物降解输尿管支架的理想材料。

Objective To evaluate the in situ biocompatibility of a new biodegradable ureteral stent made of L-lactide-glycolic acid copolymer 80：20 （PLGA 80： 20）. Methods 16 dogs served as experimental animals. Ureteral stents of PLGA 80： 20 were inserted in situ into the left ureter after transection at the mid level, then the ureters were routinely anastomosed. Ureters surrounding the stent were taken out 2, 4, 8 and 12 weeks postoperatively. The ureters were dissected to find changes of stents and local ureters. Histological analysis was performed to investigate tissue reactions to the stent and evaluate the biocompatibility. Rods of UROVISION stent served as controls. Results The PLGA stent was degraded completely within 12 weeks post implantation. In the early stage （2～4 weeks）, both stents induced epithelial hyperplasia and inflammatory cell reaction at local ureter （P〉0.05）. In the later stage （8～ 12 weeks）, the tissue reaction nearly subsided in PLGA stented ureters after degradation of the device. Whereas, the tissue reaction induced by UROVISION stent had lasted throughout the observation period, even deteriorated with time going （P〉 0.05）. Conclusion The tissue reaction induced by PLGA stent is retrievable. PLGA is regarded highly compatible and can serve as an ideal material for biodegradable ureteral stent.