芳香性维药香青兰降血脂及抗动脉粥样硬化的作用及机理研究

Dracocephalum moldavica is one of the most widely used Ugyur medicine, which has been confirmed to have cardiovascular protective effects. However, the effective substances of its pharmacodynamic effects remain unclear, as well as the mechanisms. The volatile components are specially reserved during the extraction, but there are no studies to illustrate on the pharmacodynamic effects of volatile oil. This study aimed to systematically explore the lipid-lowering and anti-atherosclerosis effects of the different extracts of dracocephalum moldavica, and whether the extracts and volatile oil have synergistical lipid-lowering effects was also investigated, by using genetically modified mice LDLR-/- and ApoCIII+ as experimental hypercholesterolemia and hyperlipemia models respectively. The mechanisms of the extracts of dracocephalum moldavica and its total flavanoids were further explored in terms of biosynthesis, catabolism of lipoproteins and liver lipid metabolism. The major ingredients of dracocephalum moldavica including tilianin were extracted to investigate its effective parts and components in vitro. Dendrimer was used as a nano-drug carrier to preliminarily study the enhancement effects on the stability, solubility and absorption of dracocephalum moldavica's extracts by incorporated the volatile oil,extracts or the effective components with PEG-PAMAM dendrimer. This study will be of far-reaching significance for clarifying the effective components and mechanisms of dracocephalum moldavica for its lipid-lowering and anti-atherosclerosis effects, and lay the foundation for the development of novel cardiovascular drugs.

香青兰是维吾尔医药中应用最为广泛的具有明确心血管保护作用的维药之一。但其药效作用的物质基础并不清楚；作用机制也不明确；制备中虽特意保留了其挥发性成分，但对其挥发油的药效作用并无研究。本课题拟采用LDLr-/-和ApoCIII+基因修饰小鼠分别为高胆固醇和高甘油三脂血症模型，系统研究比较香青兰不同提取物的降血脂和抗动脉粥样硬化的作用，并探讨提取物与挥发油间是否存在协同作用；从脂蛋白合成分泌、分解代谢、肝脏脂质代谢等方面深入研究香青兰提取物降脂的作用机制；分离香青兰提取物中包括田蓟苷在内的主要成分，在细胞水平上研究并明确香青兰降脂及抗动脉粥样硬化的有效成分。采用树状高分子为纳米药物载体，包合香青兰挥发油、提取物或有效成分，初步评价其在增加药物稳定性和溶解性，促进吸收等方面的作用。本研究将对阐明香青兰降脂及抗动脉粥样硬化作用、有效成分及机理等具有重要意义；为开发新的心血管类治疗药物奠定研究基础。

香青兰是新疆特种植物药，在维吾尔药志中作为单方药被广泛应用于动脉粥样硬化（AS）等心血管疾病的治疗，但其有效成分及作用机制尚不清楚。本研究首先提取分离了香青兰总黄酮及挥发油成分，在高脂饲料喂饲LDLR-/-和ApoCIII tg小鼠建立的高胆固醇和高甘油三酯模型上研究香青兰提取物抗AS的作用。我们的研究结果表明香青兰总黄酮不显著影响小鼠的血脂水平，但具有显著减少AS斑块形成的作用，其挥发油没有明显抗AS的作用，且挥发油对总黄酮的药效无协同增效作用。我们进一步从香青兰黄酮中分离纯化出其单体成分田蓟苷，并通过体内实验进一步证明田蓟苷是香青兰总黄酮抗AS作用的活性单体成分。我们在与AS发病机制紧密相关的三种细胞—巨噬细胞、平滑肌细胞和内皮细胞上建立了原代细胞的炎症损伤模型及泡沫细胞模型，研究比较香青兰总黄酮及田蓟苷抗AS的机制。分别在LPS刺激的小鼠腹腔巨噬细胞炎症模型和TNFα刺激的大鼠血管平滑肌细胞炎症模型上，发现田蓟苷表现出跟香青兰总黄酮一致的抗炎活性，机制与其调控TNF-α/NF-κB信号通路有关；田蓟苷可显著抑制TNF-α或ox-LDL诱导的平滑肌细胞在炎症状态下由正常的收缩型向病理性的分泌型表型的转化，抑制平滑肌细胞的增殖与迁移；田蓟苷可显著抑制ox-LDL诱导的巨噬细胞向泡沫细胞的转化，机制与其上调SR-B1和ABCA1的基因表达促进胆固醇外排，并下调SRA的基因表达抑制胆固醇吸收有关；田蓟苷对TNF-α或ox-LDL诱导的人脐静脉血管内皮细胞的炎症及氧化损伤无明显的抑制作用。因此，体外细胞模型上的机制研究结果表明，香青兰总黄酮及其单体田蓟苷通过抑制巨噬细胞与平滑肌细胞的炎症及泡沫细胞的形成抗AS。本研究对阐明香青兰的活性单体及作用机制具有重要意义，为开发抗AS的新药奠定研究基础。