新型可降解镁合金胆道支架在胆总管探查术中预防狭窄的作用

A new biodegradable stent made of magnesium alloy in preventing stenosis in the common bile duct probe

目的设计一种新型的适合应用于胆总管探查术的胆道支架,探讨其植入到动物体内的生物相容性及有效性。方法利用镁合金AZ 31B制备胆道支架。将实验犬随机分为实验组和对照组,每组6只。建立犬急性梗阻性黄疸模型,4d后胆总管直径增宽至约6mm为建模成功。实验组在胆道内放置镁合金胆道支架,并行胆总管一期缝合,对照组则单纯行应用探条扩张胆道狭窄处,并行胆道一期缝合。观察各组死亡率以及胆漏的发生率;于建模前及探查术前、术后1月、3月留取相应样本行镁离子浓度、肝功能检查;定期B超观察胆管狭窄情况;分别在探查术后1月、3月留取胆管组织标本,观察胆管的愈合情况及Masson染色观察吻合口组织胶原纤维的增生情况。结果实验组和对照组犬血液、粪便以及肝脏、心脏、脑和肺等器官中的镁离子浓度接近,实验组尿液中的镁离子浓度明显高于对照组。实验组和对照组的胆漏发生率分别为0%、16.7%,死亡率分别为16.7%、33.3%。实验组和对照组在建模前、胆总管探查术前总胆红素、碱性磷酸酶无显著性差异(P>0.05),在胆总管探查术后1月、3月总胆红素、碱性磷酸酶组间比较有显著差异(P<0.05)。胆总管探查术后1月和3月行B超检查提示实验组胆管通畅程度良好,无狭窄表现,而对照组胆管出现进行性狭窄,胆总管狭窄以上胆管明显扩张。实验组与对照组在胆总管探查术后1月、3月时,肉眼观察见胆管吻合口愈合良好;镜下观察实验组较对照组黏膜下胶原纤维沉积较少,新生肌纤维较多,管壁增厚较轻。结论镁合金胆道支架在体内具有良好的生物相容性,其良好的支撑及可降解性能在胆道探查手术及胆道良性狭窄的治疗中得到更好的应用。

Objective To design a new type of biliary stent to be used in the common bile duct probe and evaluate its biocompatibility, safety and effectiveness in a canine model. Methods Magnesium alloy （AZ 31B） was used to make biliary stents. A canine model of acute obstructive jaundice was established by ligating the distal end of the common bile duct. These dogs were divided into two groups with either placement of magnesium stent or not. The incidence of bile duct leakage and survival were evaluated. Meanwhile, we determined the concentration of magnesium in various body fluids and organs, liver function test, and ultrasonic and histological studies. Results The concentrations of magnesium in the blood, feces, liver, heart, brain and lungs were similar between the two groups. Bile leakage rate in experimental group and control group was 0% and 16.7%, respectively. The mortality was 16.7% and 33.3% control group （P〉0.05） There were no significant differences in ALP and TBIL between experimental group and before building and bile duct exploration. There were significant differences in ALP and TBIL between the two groups one and three months after bile duct probe （P〈0.05）. Biliary tract specimens showed obviously anastomotic stenosis performances and expansion performances of extrahepatic biliary in the control group, but in experimental group such changes were not observed. Ultrasonography showed that the patency of biliary anastomosis was good and there was no anastomotic biliary stricture in experimental group. However. progressive stenosis and expansion performances of extrahepatic biliary occurred in control group. There were fewer collagen fibers but more muscle fibers in experimental group than in control group. Conclusion Biliary stent made of magnesium alloy is of good biocompatibility and has the potential to prevent the postoperative stenosis in the common bile duct probe.