臺灣博碩士論文加值系統

慢性高血糖症是糖尿病的一種特徵，而臨床研究亦證明慢性高血糖症與動脈硬化的發生率呈正相關。然而，對於高血糖引發動脈硬化的機轉並無研究報導。本實驗先以Evans blue染劑注入動物體內，比較該染劑在streptozotocin (STZ) 誘發的高血糖大白鼠及對照組胸腔大動脈的分佈情形，而後再以低密度脂蛋白-膠體金粒子的複合物作為追蹤劑，探討由STZ誘發的高血糖環境對低密度脂蛋白在動脈內皮的通透路徑的影響。實驗結果發現：STZ注射後4個月的大白鼠，其血糖濃度及糖化血紅素明顯較對照組增加。而高血糖大白鼠的動脈內皮對於Evans blue染劑的通透性明顯高於對照組。高血糖的動脈血管內皮及基膜在超微結構上有明顯的改變。許多低密度脂蛋白-金粒子複合物出現於分枝區內皮細胞的小胞囊中及內皮下層;但在未分枝區，低密度脂蛋白-金粒子複合物只出現於內皮細胞的小胞囊中。統計結果顯示，在血管分枝區，低密度脂蛋白-金粒子複合物指出現於內皮細胞的小胞囊中。高血糖大白鼠內皮細胞中，含低密度脂蛋白-金粒子複合物的小胞囊體積密度顯著高於對照組 ( p<0.005 )，內皮下層的低密度脂蛋白-金粒子複合物的分佈亦顯著增加 ( p<0.005 )；而在血管未分枝區，高血糖大白鼠與對照組的內皮細胞中，含低密度脂蛋白-金粒子複合物的小胞囊體積密度並無明顯差異。在高血糖的影響下，血管分枝區中無任何型式的內皮連接結構及開啟式的細胞接合間隙均增加，而緊密式的連接結構減少；並且許多低密度脂蛋白-金粒子複合物出現於開啟式的接合間隙中。而在血管未分枝區，無任何型式的內皮連接結構細胞接合間隙均增加，緊密式的連接結構減少。由本實驗結果，顯示低密度脂蛋白在高血糖症大白鼠內皮細胞的主要通透路徑為小胞囊以及細胞間開啟式的接合間隙。在高血糖症下，動脈內皮細胞分枝區對低密度脂蛋白通透性明顯增加，極可能是糖尿病引發動脈粥瘤發生初期的一個重要因素。

Chronic hyperglycemia is a common feature of all forms of diabetes mellitus and may contribute greatly to the increase in the incidence of atherosclerosis. Yet, the mechanisms of atherosclerosis due to hyperglycemia have not been well studied. In this study, we use Evans blue to study the permeability of arterial endothelium in the streptozotocin (STZ)-induced hyperglycemic rats. We also use colloidal gold-labeled LDL to investigate in situ the transport pathways of LDL in the aortic intima of hyperglycemic rats. After 3 months into the experiment, the concentration of blood glucose and hemoglobin glycation were increased significantly in the STZ-injected animals compared with controls. The light microscopic observations indicated that the permeability of Evans blue to the aortic endothelium of hyperglycemic rats was greater than control rats. The electron microscopic observations showed that hyperglycemia generated the morphological changes in the intima. Numerous LDL-gold conjugates were revealed in the endothelium and the subendothelial layer at the branched regions of the aortic arch. The conjugates were only found in the endothelial cells but not in the subendothelial layer at the unbranched regions. Quantitative data indicated that the volume densities of plasmalemmal vesicles containing LDL-gold labelings in the branched regions of hyperglycemic rats were higher than those in the control rats (p<0.005). The incidence of labelings in the subendothelial layer was also increased in the hyperglycemic rats as compared with those in the control rats (p<0.005). Whereas in the unbranched regions, the volume densities showed no marked difference between hyperglycemic rats and the control rats. The frequencies of junctionless complexes were increased and the tight junctions were decreased respectively in both branched regions and unbranched regions of hyperglycemic rats. The frequency of open junctions was significantly increased in the branched regions after hyperglycemia, and the LDL-gold conjugates were present within most of the open junctions. From these results, we conclude that the major visible routes for transport of LDL across aortic endothelium are plasmalemmal vesicles as well as the open junctions in the hyperglycemic rats. The permeability changes in the branched regions of aortic endothelium to LDL after hyperglycemia may be an initial event in diabetes-related atherosclerosis.

目錄………………………………………………………………………1
中文摘要…………………………………………………………………3
英文摘要…………………………………………………………………5
前言………………………………………………………………………7
實驗材料及方法………………………………………………………..11
一、大白鼠高血糖症的誘發………………………………………11
二、血漿低密度脂蛋白的純化……………………………………12
三、酵素連結免疫附著法…………………………………………13
四、低密度脂蛋白之電泳分析……………………………………14
五、西方點墨法……………………………………………………14
六、膠體金粒子的製備……………………………………………16
七、膠體金粒子與低密度脂蛋白之結合…………………………16
八、陰染法…………………………………………………………17
九、免疫沈澱法……………………………………………………17
十、動物實驗………………….……………………………….…..18
十一、定量分析…………………………………………………….20
結果……………………………………………………………………..21
一、高血糖症大白鼠的確認………………………………………21
二、酵素連結免疫附著法…………………………………………21
三、西方點墨法……………………………………………………22
四、膠體金粒子與低密度脂蛋白複合體之製備…………………22
五、免疫沈澱法……………………………………………………22
六、光學顯微鏡的觀察……………………………………………23
七、電子顯微鏡觀察………………………………………………23
討論……………………………………………………………………..27
參考文獻………………………………………………………………..33
表目錄…………………………………………………………………..40
圖目錄…………………………………………………………………..41
個人資料………………………………………………………………..63

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