Toll样受体2在正常糖及高糖培养下氧化低密度脂蛋白胆固醇诱导的人脐静脉内皮细胞炎性反应的作用

The Role of Toll-Like Receptor 2 in the Infl ammatory Responses of Human Umbilical Vein Endothelial Cells Induced by Oxidized Low-Density Lipoprotein in Normal and High Glucose Culture

目的：2型糖尿病引起血管内皮细胞的损伤中，氧化低密度脂蛋白胆固醇（oxidized low-density lipoprotein, ox-LDL）起着重要作用。有证据表明，Toll样受体2（Toll-like receptor 2, TLR2）参与动脉粥样硬化的启动和发展过程。TLR2可能参与了ox-LDL在2型糖尿病细胞中的炎性反应。研究拟通过正常糖及以高糖条件下模拟2型糖尿病环境培养人脐静脉内皮细胞（HUVECs），给予不同浓度的ox-LDL，观察正常糖和高糖培养环境下的内皮细胞对ox-LDL诱导TLR2的表达是否有所改变及黏附因子的表达和它们之间的关联性。方法 HUVECs培养于糖浓度分别为2.0 g/L（正常糖）及4.5 g/L（高糖）的培养基中，分别予ox-LDL（0μg/mL，20μg/mL，40μg/mL）及LPS（10μg/mL）。通过Western blot测量TLR2及细胞间黏附分子-1（intercellular cell adhesion molecule-1, ICAM-1）的相对表达量，应用ELISA技术测量培养液中IL-6及IL-8炎性因子的含量。结果正常糖组及高糖组组间ox-LDL处理的细胞TLR2蛋白的表达无明显改变，分泌的IL-6、IL-8及ICAM-1较空白对照组明显增多，无浓度依赖性。但各组中相对于正常糖组，ox-LDL处理的培养于高糖组的细胞表达的TLR2和ICAM-1蛋白量及分泌的炎性因子IL-6和IL-8均无明显改变。结论在正常糖及高糖中，ox-LDL可以诱导引起内皮细胞炎性改变，但不伴随TLR2蛋白的表达改变，提示TLR2可能并未参与ox-LDL诱导的炎性反应。ox-LDL诱导的炎性反应程度与培养基中的糖浓度无关。

Objective Oxidized Low-density lipoprotein （ox-LDL） plays an important role in the damage of vascular endothelial cells in type 2 diabetes. Toll-like receptor 2 （TLR2） is reported to be involved in the development of atherosclerosis. It is not determined whether TLR2 is involved in the inflammatory response induced by ox-LDL in type 2 diabetes mellitus. In this experiment, we stimulate human umbilical vein endothelial cells （HUVECs） with ox-LDL under normal and high glucose conditions, mimic type 2 diabetes condition. Methods HUVECs were cultured in culture medium containing glucose concentration of 2.0 g/L （normal glucose） and 4.5 g/L （high glucose）, and then treated with ox-LDL （0μg/mL, 20μg/mL, 40μg/mL） and LPS （10μg/mL）. The expression of TLR2 and ICAM-1 protein was measured by Western blot, and interleukin （IL）-6 and -8 by ELISA.ResultsTLR2 expression was not significantly changed, while IL-6, IL-8 and ICAM-1 expression were increased in all groups treated with ox-LDL compared to control, but independent on ox-LDL concentration. TLR2, IL-6, IL-8 and ICAM-1 expression were not signifi cantly in high glucose condition compared to normal. Conclusion Ox-LDL could enhance inflammatory response in endothelial cells under the normal glucose and high glucose conditions, not associated with the change of TLR2 expression. This indicates that TLR2 may not be involved in ox-LDL-mediating infl ammatory response. The severity of infl ammatory response induced by ox-LDL is not related with the glucose concentration.