兔髂动脉球囊成形及支架术后血管壁超微结构的观察

Experimental study of ultra-microstructure of iliac artery after balloon angioplasty and stent implantation in rabbits

目的 :比较兔髂动脉球囊成形及支架术后血管壁超微结构的变化 ,探讨支架内再狭窄与球囊血管成形术后再狭窄的不同机制。方法 :10支兔 ,分别于左髂动脉行 NIR支架置入术 (S组 ) ,右髂动脉行球囊成形术 (B组 )。术前3d始予阿司匹林 2 5 mg· d- 1 ,直至处死动物。术后皮下注射肝素 2 5 0 0 U· d- 1 ,连续 7d。术后 7d和 30 d处死动物。用光镜、透射电镜及免疫组化染色技术观察损伤部位血管壁变化。结果 :术后 30 d光镜检查发现 S组新生内膜平滑肌细胞 (SMC)的增生程度明显高于 B组 (P<0 .0 5 )。电镜检查 ,术后 7d,S组较 B组可见较多从外膜向中膜及内膜迁移的肌纤维母细胞 ,中膜及内膜大量以合成型为主的 SMC,细胞外基质 (ECM)以胶原及弹性纤维为主。30 d时 B组内膜下 SMC已转化为收缩型 ,ECM以胶原及弹性纤维为主 ;而 S组内膜下大量 SMC仍为典型合成型表现 ,周围 ECM以氨基聚糖及糖蛋白为主。结论 :球囊成形术及支架术后 ,新生内膜组成成分不同 ,支架术后新生内膜增生以 SMC增生为主 ,ECM以氨基聚糖及糖蛋白为主而球囊成形术后新生内膜增生 SMC较少 。

AIM: To investigate the different mechanisms of balloon angioplasty and stent implantation by observing the ultra microstructure change of iliac artery after balloon angioplasty and stent implantation in rabbits. METHEDS: Balloon angioplasty (group B) and NIR stent implantation (group S) were performed in the right and left iliac arteries of the rabbits, respectively. 25 mg aspirine,Qd, was given to the rabbits three days before the operation until the animals were executed. 2500 U heparin was administered subcutaneously after the operation for 7 days. The animals were executed 7 and 30 days after the peration. The change of the injured arteries were observed by optical microscope, electron microscope and immunohistochemical technique. RESULTS: Under the optical microscope, 30 days after the operation, SMC proliferation in group S is much more than that of group B( P <0.05). Under the electron microscope, 7 days after the operation, more myofibroblasts migrated from adventitia to tunica media and intima in stent iliac artery than in balloon angioplasty iliac artery. Inside the media and intima,there were many synthetic type smooth muscle cells, ECM composed mainly collagen and elastin. At the time of 30 days after operation, most SMCs under the intima of group B had transformed to contractile type, and ECM composed mainly of collagen and elastin. But SMCs under the intima in group S were still synthetic type, around the SMCs,there was a lot of ECM, which was mainly composed of proteoglycans and glycoproteins. CONCLUTION: The components inside the neointima of group B and group S are different ECM in the neointima of group B is Mainly collagen and elastin, whereas the ECM in group S mainly consists of proteoglycans and glycoproteins, and there is lots of synthetic type SMCs in the neointima of group S.