Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, 76 West Yanta Road, Xi'an, 710061, Shaanxi, China.
Pflugers Arch. 2014 Feb;466(2):307-17. doi: 10.1007/s00424-013-1324-y. Epub 2013 Jul 20.
The present study was designed to investigate the role of advanced glycation end products (AGEs) in intermediate-conductance and small-conductance Ca(2+)-activated potassium channels (KCa3.1 and KCa2.3)-mediated relaxation in rat resistance arteries and the underlying mechanism. The endothelial function of mesenteric arteries was assessed with the use of wire myography. Expression levels of KCa3.1 and KCa2.3 were measured by using Western blot. Reactive oxygen species (ROS) were measured by using dihydroethidium and 2', 7'-dichlorofluorescein diacetate. KCa3.1 and KCa2.3-mediated vasodilatation responses to acetylcholine and NS309 (opener of KCa3.1 and KCa2.3) were impaired by incubation of the third-order mesenteric arteries from normal rats with AGEs (200 μg ml(-1) for 3 h). In cultured human umbilical vein endothelial cells (HUVECs), AGEs increased ROS level and decreased the protein expression of KCa3.1 and KCa2.3. Antioxidant alpha lipoic acid restored the impairment in both vasodilatation function and expression of KCa3.1 and KCa2.3. H2O2 could mimic the effect of AGEs on the protein expression of KCa3.1 and KCa2.3 in cultured HUVECs. These results demonstrate for the first time that AGEs impaired KCa3.1 and KCa2.3-mediated vasodilatation in rat mesenteric arteries via downregulation of both KCa3.1 and KCa2.3, in which the enhanced oxidative stress was involved.
本研究旨在探讨晚期糖基化终产物 (AGEs) 在大鼠阻力血管中介导性和小电导钙激活钾通道 (KCa3.1 和 KCa2.3) 介导的舒张中的作用及其机制。采用线描记法评估肠系膜动脉的内皮功能。通过 Western blot 测定 KCa3.1 和 KCa2.3 的表达水平。通过二氢乙啶和 2',7'-二氯荧光素二乙酸酯测量活性氧 (ROS)。正常大鼠第三级肠系膜动脉与 AGEs（200μg ml(-1)，孵育 3 h）孵育后，乙酰胆碱和 NS309（KCa3.1 和 KCa2.3 的开放剂）介导的 KCa3.1 和 KCa2.3 血管舒张反应受损。在培养的人脐静脉内皮细胞 (HUVEC) 中，AGEs 增加了 ROS 水平并降低了 KCa3.1 和 KCa2.3 的蛋白表达。抗氧化剂 α-硫辛酸恢复了血管舒张功能和 KCa3.1 和 KCa2.3 表达的损伤。H2O2 可以模拟 AGEs 对培养的 HUVECs 中 KCa3.1 和 KCa2.3 蛋白表达的影响。这些结果首次表明，AGEs 通过下调 KCa3.1 和 KCa2.3 损害大鼠肠系膜动脉中 KCa3.1 和 KCa2.3 介导的血管舒张，其中涉及增强的氧化应激。
