可吸收聚乙醇酸血流导向支架治疗兔宽颈动脉瘤的实验研究

Biodegradable flow-diverting stent for treatment of saccular wide-neck aneurysm in rabbits

目的探讨可吸收聚乙醇酸血流导向支架（PGA-FD）治疗颅内宽颈动脉瘤的可行性。方法将成年新西兰大白兔20只，采用弹性蛋白酶诱导制作颅内宽颈动脉瘤模型后，按随机数字表法分为3组：第1组大白兔7只，将PGA-FD置入载瘤动脉内并覆盖瘤颈，观察期为3个月：第2组大白兔7只，将裸金属支架置人载瘤动脉内并覆盖瘤颈，观察期为3个月；第3组大白兔6只，将PGA-FD置入载瘤动脉内并覆盖瘤颈，观察期为6周。观察期结束时数字减影血管造影（DSA）观察3组大白兔动脉瘤的闭塞及分支通畅情况，HE染色观察动脉瘤及载瘤动脉，弹力纤维染色检测载瘤动脉内新生内膜厚度，免疫组化染色检测载瘤动脉CD34、CD68和仪肌动蛋白（αSMA）的表达。结果第1组、第2组和第3组大白兔动脉瘤完全闭塞（4级）率分别是83．3％（5／6）、0％（0／6）、66．7％（4／6）。均未见支架所覆盖的分支狭窄或闭塞；3组大白兔载瘤动脉内新生内膜厚度分别是（111±69）μm、（70±48）μm和（190±52）μm；第3组大白兔载瘤动脉内新生内膜厚度明显高于第1组和第2组，差异有统计学意义（P〈0．05）。免疫组织化学染色显示各组载瘤动脉内新生内膜主要由αSMA阳性的平滑肌细胞和胶原纤维组成。第1、2组部分大白兔载瘤动脉新生内膜表面偶见CD34阳性的血管内皮细胞。结论在3个月的观察期内，PGA-FD可有效闭塞颅内动脉瘤，且未引起载瘤动脉明显内膜增厚或分支狭窄。

Objective To evaluate the feasibility of biodegradable flow-diverting stem for treatment ofintracranial wide-neck aneurysm. Methods Twenty adult New Zealand rabbits were used to induce wide-neck aneurysm models by elastase, and then, these models were divided into 3 groups： in group one （n=7）, biodegradable polyglycolic acid flow-diverting stents （PGA-FDs） were implanted into parent arteries and covered the necks of aneurysms; in group 2 （n=7）, the bare metal FDs replaced PGA-FDs; the observation period of animals in group one and group 2 was 3 months; in group 3 （n=6）, the PGA-FDs were implanted into parent arteries with 6 weeks of observation period. The status of aneurysm occlusion and patency of side branches covered by the stent were assessed, and all animals were sacrificed： HE staining was used to observe the thrombosis in the aneurysms, Elastic fiber staining was used to observe the neointimal thickness of parent arteries, and immuohistochemical staining was employed to detect the expressions of CD34, CD68 and alpha-actin （αSMA） in the parent arteries. Results Complete aneurysm occlusion rate in groups one, 2 and 3 was 83.3% （5/6）, 0% （0/6） and 66.7% （4/6）, respectively. The neointimal thickness in parent artery of groups one, 2 and 3 was （111 ±69）μm, （70±48）μm and （190±52） μm, respectively; that in group 3 was significantly higher than that in group one and 2 （P〈0.05）. The neointima comprised predominantly smooth muscle cells and collagen fibers. Some CD34 positive vascular endothelial cells could be seen in the neointima of parent arteries of groups one and 2. Conclusion The PGA-FD is an effective device to occlude aneurysms without inducing obvious neointimal thickness and side branch stenosis in the 3-month follow-up.