Xu Xin-Rong, Yu Hai-Tao, Yang Yan, Hang Li, Yang Xue-Wen, Ding Shu-Hua
Department of Ophthalmology, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, Nanjing 210029, China.
College of Pharmacy, Nanjing University of Traditional Chinese Medicine, Nanjing 210023, China.
Eur J Pharmacol. 2016 Jan 5;770:1-8. doi: 10.1016/j.ejphar.2015.11.050. Epub 2015 Nov 28.
Age-related macular degeneration (AMD) is a major cause of blindness worldwide. Oxidative stress plays a crucial role in the pathogenesis of dry AMD. Quercetin has potent anti-oxidative activities, but poor bioavailability limits its therapeutic application. Herein, we prepared the phospholipid complex of quercetin (quercetin-PC), characterized its structure by differential scanning calorimetry, infrared spectrum and x-ray diffraction. Quercetin-PC had equilibrium solubility of 38.36 and 1351.27μg/ml in water and chloroform, respectively, which was remarkably higher than those of quercetin alone. Then we established hydrogen peroxide (H2O2)-induced oxidative injury model in human ARPE-19 cells to examine the effects of quercetin-PC. Quercetin-PC, stronger than quercetin, promoted cell proliferation, and the proliferation rate was increased to be 78.89% when treated with Quercetin-PC at 400μM. Moreover, quercetin-PC effectively prevented ARPE-19 cells from apoptosis, and the apoptotic rate was reduced to be 3.1% when treated with Quercetin-PC at 200μM. In addition, quercetin-PC at 200μM significantly increased the activities of SOD, CAT and GSH-PX, and reduced the levels of reactive oxygen species and MDA in H2O2-treated ARPE-19 cells, but quercetin at 200μM failed to do so. Molecular examinations revealed that quercetin-PC at 200μM significantly activated Nrf2 nuclear translocation and significantly enhanced the expression of target genes HO-1, NQO-1 and GCL by different folds at both mRNA and protein levels. Our current data collectively indicated that quercetin-PC had stronger protective effects against oxidative-induced damages in ARPE-19 cells, which was associated with activation of Nrf2 pathway and its target genes implicated in antioxidant defense.
年龄相关性黄斑变性（AMD）是全球失明的主要原因。氧化应激在干性AMD的发病机制中起关键作用。槲皮素具有强大的抗氧化活性，但其较差的生物利用度限制了其治疗应用。在此，我们制备了槲皮素的磷脂复合物（槲皮素-PC），通过差示扫描量热法、红外光谱和X射线衍射对其结构进行了表征。槲皮素-PC在水和氯仿中的平衡溶解度分别为38.36和1351.27μg/ml，显著高于单独的槲皮素。然后我们在人ARPE-19细胞中建立了过氧化氢（H2O2）诱导的氧化损伤模型，以研究槲皮素-PC的作用。槲皮素-PC比槲皮素更强，能促进细胞增殖，当用400μM的槲皮素-PC处理时，增殖率提高到78.89%。此外，槲皮素-PC有效防止ARPE-19细胞凋亡，当用200μM的槲皮素-PC处理时，凋亡率降低到3.1%。此外，200μM的槲皮素-PC显著提高了H2O2处理的ARPE-19细胞中SOD、CAT和GSH-PX的活性，并降低了活性氧和MDA的水平，但200μM的槲皮素未能做到这一点。分子检测显示，200μM的槲皮素-PC显著激活Nrf2核转位，并在mRNA和蛋白质水平上以不同倍数显著增强靶基因HO-1、NQO-1和GCL的表达。我们目前的数据共同表明，槲皮素-PC对ARPE-19细胞氧化诱导的损伤具有更强的保护作用，这与Nrf2途径及其参与抗氧化防御的靶基因的激活有关。
