当归芍药散改善脑内二十二碳六烯酸代谢治疗阿尔茨海默病的作用机制研究

Alzheimer’s disease (AD) is a complex disease of the brain in which abnormalities of lipid metabolism is one of the important pathological factors. Docosahexaenoic acid (DHA) is a lipid of particular interest, because it is metabolized under enzymatic control to compounds such as neuroprotectin D1 (NPD1), which are known to reduce neuroinflammation, neutralized oxidative stress, and inhibit the production of amyloid beta (Aβ) proteins. On the other hand, however, the non-enzymatic metabolism of DHA yields products that are pro-inflammatory and that exacerbate oxidative stress in the brain. It is known that DHA is in unbalance between enzymatic and nonenzymatic metabolism, and simple dietary DHA supplementation does not improve cognitive function in patients with AD. Therefore, it is more promising therapeutically to focus on the regulatioin of DHA metabolism. Traditional Chinese medicine holds that AD pathogenesis is deficiency in origin, enrichment in symptom and a type of phlegm-stasis syndrome, and these syndromes are linked to abnormalities of lipid metabolism. Danggui-Shaoyao-San (DSS) is known to improve cognitive function in patients with AD, and is also effective on phlegm-stasis syndromes and lipid metabolism disorders. Our preliminary studies have demonstrated that DSS can improve cerebral vascular endothelial cell function and reduce Aβ proteins in the brain. The project we are now proposing focuses on the effects of DSS on DHA metabolism to study the effects of DSS on DHA metabolism, and signaling pathways based on DHA metabolism. Specially, we will examine the effects of DSS on neuroinflammation, oxidative stress, and Aβ protein production, as well as neuronal apoptosis and cognitive function to determine functional mechanisms of DSS and provide a new way in the treatment of AD.

阿尔茨海默病（AD）是成因复杂的疾病，脑部脂质代谢异常是AD的重要病理因素。二十二碳六烯酸（DHA）与AD关系尤为密切，DHA经酶代谢为神经保护素D1（NPD1），发挥减少神经炎症、氧化应激及β淀粉样（Aβ）蛋白生成作用，但DHA非酶代谢为促炎物质加重脑内氧化应激。AD患者脑内DHA呈代谢失衡状态，通过补充DHA不能提高AD患者认知功能，因此调控脑内DHA代谢成为AD治疗新思路。中医认为AD病机为本虚标实、痰瘀互结，痰瘀病理本质与脂质代谢异常密不可分。当归芍药散（DSS）不仅能改善AD患者认知功能，对脂质代谢异常痰瘀互结证也有很好疗效。我们前期研究发现DSS可改善脑血管内皮细胞功能、清除脑内Aβ蛋白。本课题着眼于DHA代谢，研究DSS对脑内DHA代谢及DHA代谢信号通路神经炎症、氧化应激和Aβ蛋白生成的作用，对神经元凋亡和认知功能的影响，探讨DSS治疗AD的作用机制，为AD治疗提供新方法。

阿尔茨海默病（AD）是成因复杂的疾病，脑部脂质代谢异常是AD的重要病理因素。二十二碳六烯酸（DHA）与AD关系尤为密切，DHA经酶代谢为神经保护素D1（NPD1），发挥减少神经炎症、氧化应激及β淀粉样（Aβ）蛋白生成作用，但DHA非酶代谢为促炎物质加重脑内氧化应激。AD患者脑内DHA呈代谢失衡状态，通过补充DHA不能提高AD患者认知功能，因此调控脑内DHA代谢成为AD治疗新思路。.项目选择经典名方当归芍药散（DSS），先对全方主要成分进行了定性定量分析。随后采用APP/PS双转基因AD模型小鼠，研究了DSS对模型小鼠脑重指数、血脂水平以及学习记忆的影响；对不同脑区（海马、前额皮质）DHA代谢以及神经炎症、氧化应激的影响。同时采用人神经元细胞及人神经母细胞瘤SH-SY5Y细胞，Aβ诱导细胞损伤造模，观察了DSS含药血清及方中主要成分（芍药苷、芍药内酯苷、川芎嗪、阿魏酸、藁本内酯）对正常及Aβ损伤细胞炎症因子、氧化应激、脂质代谢、Aβ代谢酶及细胞凋亡的影响。.DSS水提液中共检测到78种主要成分，对其中七种成分（芍药内酯苷、芍药苷、苯甲酸、没食子酸、阿魏酸、川芎内酯I、川芎内酯A）进行了定量分析，其中芍药苷含量最高。DSS水提液能改善AD模型小鼠的学习记忆障碍及血脂水平，提高小鼠海马、皮质内未酯化DHA的含量，上调DHA经酶代谢产生NPD1有关的 15-LOX和iPLA2蛋白的表达，减少炎症介质PGE2、TXB2和LTB4的生成，下调与炎症介质生成有关的cPLA2、5-LOX、12-LOX、COX-1和COX-2蛋白的表达，并能改善小鼠脑内的氧化应激状态。DSS含药血清及方中成分藁本内酯（LIG）对Aβ诱导的细胞损伤有保护作用，可通过改善细胞内炎症状态和氧化应激水平，调节Aβ代谢相关酶的蛋白表达，抑制神经细胞凋亡。DSS对Aβ诱导的神经细胞损伤有保护作用，作用机制与调节DHA代谢，改善脑内神经炎症和氧化应激状态，减少Aβ在细胞内的生成与沉积，抑制神经细胞凋亡等有关，方中的LIG可能是主要活性成分之一。本项目从调节DHA代谢角度，探讨DSS治疗AD的作用及机制，为AD的防治提供了一条新的治疗途径。