目的 探讨熊果酸对大鼠颈动脉粥样硬化(CAS)易损斑块的影响及相关机制。方法 采用随机数字表法将144只雄性SD大鼠分为对照组、模型组、熊果酸(10、20、40 mg·kg^-1)组和阿托伐他汀(ATO,2 mg·kg^-1)组,每组24只。采用高脂饮食2周+ip维生素D₃+液氮冷冻损伤血管+免疫刺激的方法制备CAS易损斑块大鼠模型,继续高脂饮食10周。造模第3周开始,各组ig给药,每天1次,连续10周。通过苏丹IV染色观察颈动脉斑块分布,计算斑块面积与管腔面积比值(PA/LA);通过HE染色、Movat五色染色观察颈动脉组织病理学改变和斑块形态,计算颈动脉斑块泡沫细胞容积分数(FVF)和胶原容积分数(CVF);生化分析法检测血清低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)水平;分光光度法检测血清丙二醛(MDA)、氧化修饰型低密度脂蛋白胆固醇(ox-LDL-C)水平;ELISA法检测血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、细胞间黏附分子1(ICAM-1)、单核细胞趋化蛋白1(MCP-1)水平;Western blotting法检测颈动脉Toll样受体4(TLR4)、核因子-κB(NF-κB)蛋白表达。结果 与对照组比较,模型组颈动脉斑块数量明显增多,PA/LA显著升高(P<0.01);颈动脉可见平滑肌细胞增多、排列紊乱、内膜增厚、大量泡沫细胞聚集等病理学改变;LDL-C、MDA、ox-LDL-C、TNF-α、IL-1β、ICAM-1、MCP-1水平显著升高而HDL-C水平显著降低(P<0.01);TLR4、NF-κB蛋白表达量显著升高(P<0.01)。与模型组比较,熊果酸20、40 mg·kg^-1组和ATO组颈动脉斑块数量明显减少,PA/LA显著降低(P<0.01);颈动脉病理学改变明显改善,FVF显著降低、CVF显著升高(P<0.01);LDL-C、MDA、ox-LDL-C、TNF-α、IL-1β、ICAM-1、MCP-1水平显著降低且HDL-C水平显著升高(P<0.01);TLR4、NF-κB蛋白表达量显著降低(P<0.01)。结论 熊果酸具有减少和稳定大鼠CAS易损斑块的作用,其机制可能与抑制TLR4/NF-κB通路,进而抑制炎症反应和氧化应激有关。

Objective To investigate the effect of ursolic acid (UA) on vulnerable plaques in rats with carotid atherosclerosis (CAS) and related mechanisms. Methods Totally 144 male SD rats were randomly divided into control group, model group, UA (10, 20, 40 mg·kg^-1) group and atorvastatin (ATO) 2 mg·kg^-1 group. The CAS vulnerable plaque rat models were prepared by high-fat diet for two weeks + ip injection of vitamin D₃ + liquid nitrogen to freeze blood vessels + immune stimulation, and after continuing high-fat diet for 10 weeks. Starting from the 3rd week of modeling, the drugs were given by intragastric administration, once a day. The plaque distribution was observed through Sudan IV staining, and the ratio of plaque area to lumen area (PA/LA). The histopathological changes and plaque morphology of the aorta were observed by HE staining and Movat five-color staining. The level of low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) in serum were detected by biochemical analysis method; the level of malondialdehyde (MDA), oxidatively modified low-density lipoprotein (ox-LDL-C) were detected by spectrophotometric. The level of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), intercellular adhesion molecule 1 (ICAM-1), monocyte chemotactic protein 1 (MCP-1) were detected by ELISA method; the expression of aortic toll-like receptor 4 (TLR4), nuclear factor-κB (NF-κB) were detected by Western blotting. Results Compared with control group, the number of aortic plaques in the model group increased, and the PA/LA significantly increased (P<0.01). The physiological changes of aorta showed increased smooth muscle cells, disordered arrangement, intimal thickening, large number of foam cell accumulations. The level of LDL-C, MDA , ox-LDL-C, TNF-α, IL-1β, ICAM-1, MCP-1 significantly increased while the level of HDL-C significantly decreased (P<0.01). The expression of TLR4, NF-κB were significantly increased (P<0.01). Compared with model group, the number of aortic plaques in the UA 20, 40 mg·kg^-1 group and ATO 2 mg·kg^-1 group was significantly decreased, and the PA/LA was significantly reduced (P<0.01). The pathological changes of the aorta were significantly improved, the FVF was significantly decreased and the CVF was significantly increased (P<0.01). The level of LDL-C, MDA, ox-LDL-C, TNF-α, IL-1β, ICAM-1, MCP-1 significantly decreased and the level of HDL-C significantly increased (P<0.01). The expression of TLR4, NF-κB were significantly decreased (P<0.01). Conclusion UA has the effect of reducing and stabilizing vulnerable plaques of CAS in rats, which mechanism may be related to inhibiting the TLR4/NF-κB pathway, and then inhibiting inflammation and oxidative stress.

R285.5

河北省邯郸市科学技术研究与发展计划项目(1823208043ZC)