可降解外支架预防高脂血症兔自体移植静脉再狭窄

Prevention of restenosis of autologous vein graft by biodegradable external stent in hyperlipemia rabbits

目的探讨在高脂内环境下聚乙醇酸（PGA）可降解血管外支架对自体移植静脉（VG）再狭窄的防治作用。方法建立高脂血症（HLP）兔颈内静脉-颈动脉移植模型，实验组VG应用PGA外支架保护，而对照组VG无外支架保护；分别于术前和术后4、8、12、20周获取VG，比较两组VG的再狭窄率及其内皮型一氧化氮合酶（eNOS）蛋白表达、一氧化氮（NO）生成量和组织形态变化的差异。结果对照组有4支VG出现再狭窄，而实验组无再狭窄。术后实验组VG与对照组比较：eNOS蛋白表达、NO生成量显著升高（P〈0．05），脂质沉积明显减轻，内皮完整性较好，术后12、20周内、中膜增厚显著减轻（P〈0．05）。结论高脂内环境下PGA外支架可有效预防VG再狭窄，作用可持续至外支架降解后。其机制与外支架保护和改善内皮功能，抑制VG的非适应性重塑有关。

Objective Toinvestigate preventive effect of the polyglycolic acid （PGA） biodegradable external stent on restenosis of autologous vein graft in hyperlipemia rabbits. Methods Jugular vein grafts with or without biodegradable external stent were interposed into carotid arteries of hyperlipemia rabbits. The vein grafts were harvested at 0, 4, 8, 12 and 20 weeks after implantation respectively and were examined with oil red ＂0＂, HE, VB and immunohistochemical staining and scanning electron microscopy. NO production was detected by the way of nitrate reductase. The flow condition in the vein grafts were checked with ultrasonography. The expression of eNOS, NO production and histomorphological variation were compared. Results Restenosis was no found in sheathed grafts （ with biodegradable external stent）. The expression of eNOS and NO production in sheathed grafts were higher than those in unsheathed grafts （without biodegradable external stent）. Sheathed grafts significantly reduced intimal and medial thickening and lipids deposition as compared with unsheathed grafts at 12 and 20 weeks after implantation. Conclusion The PGA external stent can prevent restenosis of vein grafts in hyperlipemia rabbits, which persists in long term, even after degradation of stent itself. The preventive mechanism of biodegradable external stem on restenosis of vein graft may be related to the improvement of endothelium function and inhibition of the contractive vessel remodeling.