目的 基于Toll样受体4（Toll-like receptor 4，TLR4）/髓样分化因子88（myeloid differentiation factor 88，MyD88）/核因子-κB（nuclear factor-κB，NF-κB）通路探讨大蒜素对动脉粥样硬化小鼠的作用及其机制。方法 24只ApoE^-/-小鼠随机分为模型组、阿托伐他汀（2.6 mg/kg）组和大蒜素（20 mg/kg）组，每组8只，给予高脂饲料喂养8周。另取8只C57BL/6N野生型小鼠作为对照组，给予普通饲料喂养。给予药物干预9周后，利用油红O染色观察小鼠主动脉斑块面积，苏木素-伊红（hematoxylin-eosin，HE）染色观察小鼠肝脏病理变化；利用生化法检测小鼠血清总胆固醇（total cholesterol，TC）、三酰甘油（triglycerides，TG）、高密度脂蛋白胆固醇（high density lipoprotein cholesterol，HDL-C）、低密度脂蛋白胆固醇（low density lipoprotein cholesterol，LDL-C）水平及天冬氨酸氨基转移酶（aspartate aminotransferase，AST）、丙氨酸氨基转移酶（alanine aminotransferase，ALT）、碱性磷酸酶（alkaline phosphatase，ALP）活性，检测肝脏TC、TG、游离胆固醇（free cholesterol，FC）水平；利用ELISA法检测小鼠血清25-羟基胆固醇（25-hydroxycholesterol，25-HC）、白细胞介素-6（interleukin-6，IL-6）、IL-1β、肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）水平；利用Western blotting检测肝脏中胆固醇25羟化酶（cholesterol 25 hydroxylase，CH25H）、TLR4、NF-κB、磷酸化NF-κB（phosphorylated NF-κB，p-NF-κB）、MyD88、IL-1β蛋白表达。结果 大蒜素能显著抑制高脂饮食诱导的ApoE^-/-小鼠主动脉斑块形成和肝脏的脂肪变性（P＜0.01），降低血清TC、TG、LDL-C、non-HDL-C、25-HC、IL-6、IL-1β、TNF-α水平以及动脉粥样硬化指数（P＜0.05、0.01）。此外，大蒜素能降低肝脏TC、TG和FC水平（P＜0.01），抑制肝脏中CH25H、TLR4、MyD88、p-NF-κB和IL-1β蛋白表达（P＜0.05、0.01）。结论 大蒜素通过改善脂质代谢和抑制炎症反应，进而抑制动脉粥样硬化小鼠主动脉的脂质斑块沉积，其作用机制可能与降低肝脏CH25H水平以及抑制TLR4/MyD88/NF-κB通路有关。

Objective To explore the effect and mechanism of allicin on atherosclerosis in mice based on Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88)/nuclear factor-κB (NF-κB) pathway. Methods A total of 24 ApoE^-/- mice were randomly divided into model group, atorvastatin (2.6 mg/kg) group and allicin (20 mg/kg) group, with eight mice in each group, and fed with high-fat diet for eight weeks. Another eight C57BL/6N wild-type mice were selected as the control group and fed with regular feed. After nine weeks of drug intervention, the area of aortic plaques in mice was observed using oil red O staining, and the pathological changes in liver of mice was observed using hematoxylin-eosin (HE) staining. Biochemical method was used to detect the levels of total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), as well as the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in serum of mice, and to measure the levels of TC, TG and free cholesterol (FC) in liver. ELISA method was used to detect the levels of 25 hydroxycholesterol (25-HC), interleukin-6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) in serum of mice. Western blotting was used to detect cholesterol 25 hydroxylase (CH25H), TLR4, NF-κB, phosphorylated NF-κB (p-NF-κB), MyD88 and IL-1β protein expressions in liver. Results Allicin could significantly inhibit the formation of aortic plaque and liver steatosis in ApoE^-/- mice induced by high-fat diet (P < 0.01), reduce the levels of TC, TG, LDL-C, non-HDL-C, 25-HC, IL-6, IL-1β, TNF-α in serum and atherosclerosis index (P < 0.05, 0.01). In addition, allicin could reduce TC, TG and FC levels in liver (P < 0.01), and inhibit the expressions of CH25H, TLR4, MyD88, p-NF-κB and IL-1 β proteins in liver (P < 0.05, 0.01). Conclusion Allicin can inhibit the deposition of lipid plaque in the aorta of atherosclerotic mice by improving lipid metabolism and inhibiting inflammatory response. Its mechanism may be related to the reduction of CH25H level in liver and the inhibition of TLR4/MyD88/NF-κB pathway.

R285.5

国家自然科学基金资助项目(82261138556)