脂多糖直接损伤血管内皮细胞后内皮细胞膜脂的修饰

我们前期的研究显示,脂多糖（lipopolysaccharide,LPS）直接损伤人脐静脉血管内皮细胞（human umbilical vein endothelial cell,HUVEC）后,HUVEC膜粘度随LPS浓度的增加而增大,这暗示LPS可能改变HUVEC的膜结构和组成。本文旨在研究LPS直接损伤HUVEC后内皮细胞膜脂的修饰。用高效毛细管电泳（high performance capillary electrophoresis,HPCE)污测定HUVEC膜磷脂组成,HUVEC用不同浓度（O、0.3125、0.625、1.25、2.5、5、7、8.5、9、10μg/ml）的LPS无血清培养液直接损伤3h;用含LPS（0.625μg/ml）的无血清培养液直接损伤1、3、6、12、24、48h。结果显示：在3h LPS的作用下,HUVEC的总磷脂含量随LPS浓度的增加而增加,在0.625μg/ml LPS的浓度条件下,HUVEC的总磷脂含量随LPS作用时间的延长而降低;LPS的作用浓度和作用时间对磷脂酰鞘磷脂（SM）、磷脂酰乙醇胺（PE）以及磷脂酰丝氨酸（PS）的含量影响不大。LPS激活膜磷脂代谢的反应特性表现出典型的酶促动力学特性。实验结果表明,LPS可直接激活血管内皮细胞膜磷脂代谢,诱导HUVEC膜磷脂的修饰,提示LPS直接损伤血管内皮细胞HUVEC的途径可能与膜结构组成及膜脂代谢有关。

Modification of membrane lipid of human umbilical vein endothelia cells after direct lipopolysaccharide injury

Our previous study showed that the membrane viscosity of human umbilical vein endothelial cells (HUVECs) increased with lipopolysaccharide (LPS) concentration after direct LPS damaging, implying that LPS could change the membrane structure and composition of HUVECs. The purpose of the present study was to investigate the modification of HUVECs membrane lipid by LPS under direct LPS injury to HUVECs. Phospholipid components of HUVEC membrane were determined with high performance capillary electrophoresis (HPCE), and HUVECs were directly damaged by LPS of different concentrations: 0, 0.313, 0.625, 1.25, 2.5, 5 and 10 microgram/ml for 3 h, and by 0.625 microgram/ml for 1, 3, 6, 12, 24 and 48 h. The results show that total phospholipid content of HUVECs increased with the increase of LPS concentration at 3 h, and decreased with the duration of LPS effect at 0.625 microgram/ml. Phosphatidylinositol (PI) and phosphatidylcholine (PC) contents increased with the increase of LPS concentration and decreased with the duration of LPS effect; LPS contents and its effect duration had slight effect on sphingomyelin (SM), phosphatidylethanolamine (PE) or phosphatidylserine (PS) contents. The LPS activating effect of HUVEC membrane lipid showed a typical property of enzymatic dynamics. These experimental results indicate that LPS directly activates the metabolism of HUVEC membrane lipid and induces the modification of HUVEC membrane phospholipid, which implies that the mechanism of the impairment of HUVECs by LPS may be related to the membrane structure of HUVECs and the metabolism of HUVEC membrane lipid.