Department of Coronary Disease, Fuwai Huazhong Cardiovascular Hospital, Zhengzhou, China.
J Cardiovasc Pharmacol. 2019 Aug;74(2):162-171. doi: 10.1097/FJC.0000000000000699.
Atherosclerosis (AS) contributes to the development of several cardiovascular diseases such as myocardial infarction and stroke. Oxidized low-density lipoprotein (Ox-LDL)-induced endothelial cell injury plays a key role in the pathogenesis of AS. Thus, this study was conducted to examine the effects of a naturally occurring flavonoid compound, xanthoangelol (XAG), on Ox-LDL-induced cell injury.
Human umbilical vein endothelial cells (HUVECs) were used as the in vitro cell model. The number of viable cells was determined using CCK-8 assay. Cell apoptosis was detected using Hoechst staining. Percentage of apoptotic cells was quantified by flow cytometry. The cellular levels of malondialdehyde (MDA), superoxide dismutase, catalase (CAT), and glutathione peroxidase were determined using enzyme-linked immunosorbent assays. The cellular reactive oxygen species level was detected by flow cytometry after fluorescence staining. The mRNA expression levels of nuclear factor-E2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), and NQO-1 were determined using quantitative real-time polymerase chain reaction assay. The protein levels of cleaved caspase-3, cleaved poly ADP-ribose polymerase, Bax, Bcl-2, Nrf2, Keap1, HO-1, and NQO-1 were measured by using Western blot assay. The HUVECs were transfected with Nrf2 siRNA to reduce the expression of Nrf2.
XAG could effectively protect against Ox-LDL-stimulated cell death in HUVECs. These cytoprotective effects were due to its anti-apoptotic and anti-oxidant activities, as supported by the increase of SOD, CAT, and glutathione peroxidase activities, and the decrease of MDA and reactive oxygen species levels in injured HUVECs induced by Ox-LDL. Moreover, the results showed that XAG activated Nrf2/ARE signaling in a dose-dependent manner. Importantly, blockade of Nrf2 signaling using siRNA or specific inhibitor notably abolished the cytoprotective activities of XAG.
These data suggest that XAG cytoprotects against Ox-LDL-induced cell injury through activating Nrf2/ARE-mediated antioxidative stress. Cumulatively, these findings show that EX has the potential to prevent and treat AS.
动脉粥样硬化（AS）可导致多种心血管疾病的发生，如心肌梗死和中风。氧化型低密度脂蛋白（Ox-LDL）诱导的内皮细胞损伤在 AS 的发病机制中起关键作用。因此，本研究旨在探讨一种天然黄酮类化合物，即黄当归醇（XAG），对 Ox-LDL 诱导的细胞损伤的影响。
人脐静脉内皮细胞（HUVEC）作为体外细胞模型。采用 CCK-8 法测定细胞活力。采用 Hoechst 染色检测细胞凋亡。采用流式细胞术检测凋亡细胞的百分比。采用酶联免疫吸附试验测定丙二醛（MDA）、超氧化物歧化酶、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶的细胞内水平。采用流式细胞术荧光染色法检测细胞内活性氧（ROS）水平。采用实时定量聚合酶链反应（qPCR）法测定核因子 E2 相关因子 2（Nrf2）、血红素加氧酶-1（HO-1）和 NADPH 醌氧化还原酶 1（NQO-1）的 mRNA 表达水平。采用 Western blot 法测定裂解型半胱天冬酶-3、裂解型多聚 ADP-核糖聚合酶、Bax、Bcl-2、Nrf2、Keap1、HO-1 和 NQO-1 的蛋白水平。用 Nrf2 siRNA 转染 HUVEC 以降低 Nrf2 的表达。
XAG 可有效抑制 Ox-LDL 刺激的 HUVEC 细胞死亡。这些细胞保护作用归因于其抗凋亡和抗氧化活性，这表现在 Ox-LDL 诱导的 HUVEC 中 SOD、CAT 和谷胱甘肽过氧化物酶活性的增加，以及 MDA 和 ROS 水平的降低。此外，结果表明 XAG 以剂量依赖的方式激活 Nrf2/ARE 信号通路。重要的是，使用 siRNA 或特异性抑制剂阻断 Nrf2 信号通路显著消除了 XAG 的细胞保护作用。
这些数据表明，XAG 通过激活 Nrf2/ARE 介导的抗氧化应激来保护 HUVEC 免受 Ox-LDL 诱导的细胞损伤。综上所述，这些发现表明 XAG 具有预防和治疗 AS 的潜力。
