花色苷对AGEs介导的非酒精性脂肪肝纤维化的抑制作用及机制研究

The prevalence rate of non-alcoholic fatty liver disease (NAFLD) in China is extremely high, and NAFLD patients could finally develop to non-alcoholic fatty hepatitis and fibrosis stage. Recent studies showed that the development of NAFLD fibrosis was highly correlated with glycosylation end products (AGEs), which existed in both food source or the body with disordered metabolism. According to our previous studies, anthocyanins as a group of polyphenols widely existed in nature, showed a protective effect on NAFLD and related liver fibrosis, however, the mechanism has not been clearly explored. This research program intends to adopt animal models to reveal the beneficial effects of cyanidin-3-O-glucoside (C3G) as the main monomer of anthocyanins on AGEs mediated NAFLD fibrosis, and investigate the C3G related signaling pathways, such as RAGE, AGE-Rs, and NOXs. In addition, C3G and its main metabolites protocatechuic acid (PCA) are used for the intervention on hepatic stellate cells (HSC) in vitro, and further to investigate the inhibition effects of the activation of HSC as well as fibrosis genes expression. Trying to uncover the mechanism of C3G suppressing on the activation of AGEs mediated hepatic stellate cell, to investigate the related signaling pathway and verify its reaction target. This study will provide the theoretical basis of anthocyanins protect against AGEs mediated NAFLD fibrosis, and supply the data for dietary guidance or nutritional intervention on NAFLD patients.

非酒精性脂肪肝（NAFLD）患病率高，且可能发展到难以逆转的非酒精性脂肪肝炎及纤维化阶段。近期研究表明，NAFLD的纤维化发展与食源或体内代谢紊乱产生的糖基化终末产物（AGEs）高度相关，我们前期研究表明花色苷作为广泛存在的植物化学物展示出了良好的肝损伤保护作用，但其抗纤维化机制有待深入探讨。本项目拟采用动物模型探讨花色苷的主要单体矢车菊素-3-葡萄糖苷（C3G）对AGEs暴露下NAFLD肝纤维化及星状细胞（HSC）活化的抑制效果，并结合体外HSC的干预研究，揭示C3G及其体内代谢产物原儿茶酸（PCA）对AGEs介导的受体RAGE、AGE-Rs及NOXs等细胞信号通路的影响；通过基因干扰，并进行靶分子重组蛋白的表面等离子共振研究，明确C3G及PCA在HSC活化通路中的作用靶点。本研究将为花色苷防治AGEs介导的NAFLD纤维化提供理论基础，并对相关高危人群的膳食指导及营养干预提供理论依据。

非酒精性脂肪肝是一种常见的肝病，其患病率在逐年上升，然而其重视程度及防治措施都远远不够。日常摄入的食品中的有害物也有可能加重非酒精性脂肪肝，而有些天然活性食物因子可能改善脂肪肝。本研究发现非酒精性脂肪肝合并晚期糖基终末产物这种食品中有害物会对肝脏的脂肪变性程度及炎症有显著促进作用，而膳食花色苷作为一种广泛存在的天然多酚类色素可以有效抑制小鼠的脂质代谢紊乱。小鼠分别喂养烘烤后的标准饲料（AIN-93M），蛋氨酸胆碱缺乏（MCD）饲料，烘烤后的MCD饲料（BMCD）建立模型，并在BMCD饲料的基础上进行花色苷灌胃干预（60 mg/kg或120 mg/kg）5周后，处死小鼠。通过组织学检测，发现烘烤后的MCD饲料明显加重了肝脏的炎症水平及肝损伤，而花色苷对脂质蓄积、炎症均有很好的抑制作用。经过肝脏蛋白质组学分析发现，花色苷对脂质代谢、线粒体、外泌体等相关通路影响较为明显。我们进一步用通过蛋白免疫印迹发现花色苷对脂质的调节是通过CD36，ACC，FASN，FABP4等脂质合成酶的抑制实现的，而对ATGL，CPT-1的脂质分解酶类影响很小。本研究对花色苷的调节脂质代谢的作用和机制进行了系统地探讨，对未来花色苷的膳食指导及产品开发奠定了良好的理论基础。