低密度脂蛋白对动脉壁内皮细胞膜血栓调节蛋白功能的影响

通过不同浓度的低密度脂蛋白与体外培养的新生小牛主动脉内皮细胞经不同时间孵育后，应用凝血酶、蛋白Ｃ和Ｓ－２２３８发色底物显色法，观察单层内皮细胞膜上血栓调节蛋白功能的变化。结果显示：低密度脂蛋白孵育浓度＞６ｍｇ·Ｌ－１时．血栓调节蛋白活性降低，两者呈良好的负相关（ｙ＝－０．２５ｘ＋６５．９６，ｒ＝－０．８７，ｎ＝１７５，Ｐ＜０．００１）；浓度≥５０ｍｇ·Ｌ－１时，随着孵育时间延长，血栓调节蛋白受抑制较显著，并呈相关性；低密度脂蛋白还使血栓调节蛋白辅助激活蛋白ｃ的反应速率出现早、中期减慢，后期加快的变化．这些变化表明低密脂蛋白具有形响血栓调节蛋白功能的作用，提示高脂血症可以通过抑制动脉血管壁局部抗凝功能来促进动脉粥样硬化的发生发展．

Effect of Low Density Lipoprotein on Thrombomodulin Function of the Surface of Cultured Bovine Aortic Endothelial Cells

To explain the relationship between low density lipoprotein(LDL) and local anticoagulation in the atherosclerotic pathogenesis, the effect of varied LDL concentration with different incubation time on the activation of protein C by thrombomodulin (TM) of the surface of cultured newborn bovine aortic endothelial cells was investigated. After incubation, thrombin, protein C, and S-2238 were used for measuring TM-dependent protein C activation. The results showed a significant decline of TM activity after incubation with over 6 mg·L-1 of LDL and a significantly negative correlation between the LDL concentration and TM activity (y=-0. 25x + 65.96, r=-0. 87, n= 175, p<0. 001 ). The longer the incubation time with more than 50 mg·L-1 of LDL was taken, the more significant inhibition of TM activity would be shown. Reaction rate of activated protein C generation was decreased in early, and increased later.These data suggest that elevated blood levels of LDL may contribute to the atherosclerotic pathogenesis by decreasig function of local anticoagulation.