Emergency Medicine Research Team, Tabriz University of Medical Sciences, Tabriz, Iran; Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Applied Cell Sciences, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
Phytomedicine. 2019 Mar 15;56:183-193. doi: 10.1016/j.phymed.2018.11.008. Epub 2018 Nov 8.
Quercetin, a flavonoid antioxidant, has been found to exert therapeutic effects in diabetic condition. Autophagy represents a homeostatic cellular mechanism for the turnover of unfolds proteins and damaged organelles through a lysosome-dependent degradation manner. We speculated that quercetin could protect endothelial cells against high glucose-induced damage by promoting autophagic responses.
HUVECs viability was evaluated by MTT method. Griess and TBARS assays were used to monitor the levels of NO and MDA, respectively. Intracellular ROS generation was determined in DCFDA-stained cells analyzed by flow cytometry. To investigate the role of quercetin in endothelial cell migratory behavior, we used a scratch test. The level of autophagy proteins LC3, Beclin-1 and P62 were measured by western blotting technique.
Our results showed that quercetin had the potential to increase cell survival after exposure to high glucose (P < 0.05). Total levels of oxidative stress markers were profoundly decreased and the activity of GSH was increased by quercetin (P < 0.05). High glucose suppressed HUVECs migration to the scratched area (P < 0.05). However, a significant stimulation in cell migration was observed after exposure to quercetin (P < 0.05). Based on data, autophagy was blocked at the late stage by high glucose concentration while quercetin enhanced autophagic response by reducing the P62 level coincided with the induction of Beclin-1 and LC3-II to LC3-I ratio (P < 0.05). All these beneficial effects were reversed by 3-methyladenine as an autophagy inhibitor.
Together, our data suggest that quercetin could protect HUVECs from high glucose induced-damage possibly by activation of the autophagy response.
槲皮素是一种类黄酮抗氧化剂，已被发现对糖尿病有治疗作用。自噬是一种通过溶酶体依赖的降解方式来实现未折叠蛋白和受损细胞器更新的细胞内稳态机制。我们推测，槲皮素可以通过促进自噬反应来保护内皮细胞免受高糖诱导的损伤。
通过 MTT 法评估 HUVECs 的活力。使用 Griess 和 TBARS 测定法分别监测 NO 和 MDA 的水平。通过流式细胞术分析 DCFDA 染色细胞来测定细胞内 ROS 的产生。为了研究槲皮素在内皮细胞迁移行为中的作用，我们使用划痕实验。通过 Western 印迹技术测量自噬蛋白 LC3、Beclin-1 和 P62 的水平。
我们的结果表明，槲皮素在暴露于高葡萄糖后具有增加细胞存活的潜力（P<0.05）。总氧化应激标志物水平显著降低，GSH 活性增加（P<0.05）。高葡萄糖抑制 HUVECs 迁移到划痕区域（P<0.05）。然而，暴露于槲皮素后观察到细胞迁移明显增加（P<0.05）。基于这些数据，高葡萄糖浓度在晚期阻断自噬，而槲皮素通过降低 P62 水平增强自噬反应，同时诱导 Beclin-1 和 LC3-II 向 LC3-I 比值增加（P<0.05）。所有这些有益作用都被自噬抑制剂 3-甲基腺嘌呤逆转。
综上所述，我们的数据表明，槲皮素可以通过激活自噬反应来保护 HUVECs 免受高糖诱导的损伤。
