高脂饮食诱导兔自体静脉移植后动脉硬化特点

目的　探讨高脂饮食诱导兔自体静脉移植动脉硬化的结构特点 ,为静脉搭桥后再狭窄的防治提供资料。方法　兔 2 5只 ,均实施自体血管移植术 ,术后按不同的饲高脂饮食时间段分为 5组。按不同时间点取材分 5组。光、电镜观察。结果　光镜下移植段管壁逐渐增厚 ,内膜泡沫细胞逐渐增多 ,12周时内膜的全层和中膜的内层充满了大量泡沫细胞 ,细胞间质较少 ;移植后早期可见内皮表面有较多的白细胞粘附并浸润到内皮下层 ,对照侧静脉和颈总动脉偶见泡沫细胞。电镜下中膜平滑肌细胞由收缩型转变为合成型 ,移植后两周时达到高峰。对照静脉内皮细胞呈长梭形 ,无微绒毛 ;在移植后 1～ 2周 ,移植段内皮的形态呈圆形 ,椭圆形或梭形等多种形态 ,有丰富的长而密的微绒毛 ,随着时间的延长 ,移植段可见成片的 ,局灶性内皮脱落。结论　自体静脉移植后 ,对高脂诱导动脉硬化的易感性高于原位血管 ;移植段管壁增厚可能与血流动力学改变和平滑肌转型、增殖、产生基质有关

Atherosclerotic Features Induced by High-fat Diet after Autogenous Vein Graft in Rabbits

Objective To explore the atherosclerotic structural features induced by high-fat food after autogenous vein graft in rabbit to provide the data for the prevention of restenosis after vein bypass graft. Methods 25 rabbits were divided averagely into five groups and operated with autogenous vein graft, and fed with high cholesterol food. The relative blood vessel segments were harvested at the different intervals postoperatively and observed under light and electron microscope. Results The grafted vein wall was thicken and number of foam cells increased gradually in intima and inner part of medial tunica with less intercellular substance between foam cells, and artery and the adhesion and infiltration of leukocytes were seen in the early time after graft under light mcroscope, and few foam cells ere found in the vien and artery of control. Smooth muscle cell (SMC) phenotype was changed from contractile phynotype to synthetic one with maximum at the end of second week after operation, the endothelial cells of grafted vein was found with various shapes and rich long dense microvilli, and endothelial cells desquamated locally as the time past under electron microscope. But in control vein, endothelial cells are fusiform without microvilli. Conclusions The susceptibility to atherosclerosis in grafted vein is higher than that of the blood vessels in situ, SMCs phenotype change, proliferation and synthesis of extracellular ma trix and the changes of blood flow dynamics maybe contribute to the changes of the wall.