依折麦布辛伐他汀片对兔腹主动脉粥样硬化斑块逆转作用的实验研究

Effects of ezetimibe/simvastatin tablets on atherosclerotic plaque regression of abdominal arteries in rabbits

摘要:

目的 观察腹主动脉粥样斑块内炎性巨噬细胞和平滑肌细胞的表达情况，以探索依折麦布联合他汀类药物在逆转动脉斑块中的作用及机制。方法 选取24只健康雄性新西兰大耳白兔，随机分为对照组（n＝8）和高胆固醇血症组（n＝16）。对照组给予普通饲料，喂养12周。高胆固醇血症组喂饲致动脉粥样硬化饲料（由普通颗粒饲料＋15g/L胆固醇＋100g/L猪油＋150g/L蛋黄粉组成）2周后行腹主动脉内膜球囊拉伤术，术后再随机分为模型亚组和依折麦布辛伐他汀（ES）亚组（给予5/10mg/（kg·d）每组8只，两亚组均继续喂饲致动脉粥样硬化饲料10周。喂养第12周时活杀动物，取腹主动脉进行石蜡切片。检测不同时间点脂质和脂蛋白，应用光学显微镜观察动脉粥样硬化进程，采用免疫组化方法分析巨噬细胞和平滑肌细胞在斑块处的表达。结果 ES亚组的血清总胆固醇（TC）、甘油三酯（TG）、低密度脂蛋白胆固醇（LDL-C）浓度明显低于模型亚组（P＜0.01）。病理检测显示两亚组及ES亚组斑块直径、斑块厚度和动脉内/中膜厚度经单因素方差分析，差异有统计学意义（P＜0.05）。免疫组化检测结果示ES亚组血管壁中巨噬细胞的表达量较模型亚组显著减少（P＜0.05），而平滑肌细胞的表达量较模型亚组显著增多（P＜0.01）。结论 ES可能通过减少细胞外脂质的沉积，减少内膜和中膜巨噬细胞的数量和胆固醇的含量，增加胶原和平滑肌细胞面积，从而起到逆转斑块的作用。

Abstract:

Objective To observe the efficiency of ezetimibe/simvastatin (ES) tablets on the regression of atherosclerotic plaque of abdominal arteries in rabbits. Methods Twenty-four healthy male New Zealand rabbits were randomly divided into 2 groups: control group (n＝8) and hypercholesterolemia group (n＝16). Control group was fed with normal diet for 12 weeks. The other group animals were given a cholesterol-supplemented diet (normal diet＋15g/L cholesterol＋100g/L lard＋150g/L egg yolk powder) for 2 weeks, and underwent catheter-induced arterial wall injury. These rabbits were then randomized to model subgroup (n＝8, for another 10 weeks of hypercholesterol diet) and ES treatment subgroup [n＝8, 5/10mg/(kg·d) for another 10 weeks]. Chinese russell’s viper venom was intra-peritoneally injected to trigger plaque rupture. Abdominal aortagraphy was carried out to measure the aorta stenosis. After 12 weeks’ feeding, all rabbits were sacrificed, and their abdominal arteries were isolated, paraffin-embedded and then sectioned. Blood lipid and lipoproteins were detected. The development of the atherosclerotic plaques was evaluated through the light microscopy. Finally, the expression of macrophage and smooth muscle actin in the abdominal arteries was measured by immunohistochemical analysis. Results The serum levels of total cholesterol (TC), triglycerides (TG) and low density lipoprotein-cholesterol (LDL-C) were significantly lower in the ES treatment subgroup than in the hypercholesterolemia model group (P＜0.01). One-way analysis of variance indicated that significant differences were found in the plaque diameter, plaque thickness and the intimal-medial thickness between the ES subgroup and hypercholesterolemia model subgroup by morphological observation (P＜0.05). Immunohistochemical analysis showed that lesser macrophages (P＜0.05) but more smooth muscle cells (P＜0.01) were found in the ES treatment subgroup than in the model group. Conclusion It may be through reducing the deposition of extracellular lipids that ES treatment decreases macrophage number and cholesterol level, increases the collagen and smooth muscle cells in the arterial intima and media, and thus exerts effect on plaque reversing.