雷帕霉素对动脉粥样硬化小鼠的治疗作用及机理

Therapeutic effect and mechanism of rapamycin on atherosclerotic mice

目的:探讨了雷帕霉素对动脉粥样硬化小鼠的治疗效果以及作用机理。方法:选取30只ApoE基因缺陷小鼠,采用高脂喂养建立动脉粥样硬化(AS)模型。建模成功后将小鼠随机分为模型组和实验组,同时选取15只正常小鼠作为对照组。实验组小鼠经尾静脉注射雷帕霉素10mg/kg,对照组和模型组小鼠经腹腔注射等体积生理盐水。治疗1周处死小鼠,取血清和培养原代主动脉平滑肌细胞,采用免疫荧光分析主动脉平滑肌细胞自噬和脂质水平;采用自动生化检测仪分析每组小鼠血脂变化;采用HE染色分析主动脉病理变化;采用ELISA测定小鼠外周血和平滑肌细胞培养上清炎症因子TNF-α、IL-6和IL-1β的水平。结果:与模型组比较,实验组小鼠主动脉平滑肌细胞自噬底物LC3点的数量显著增多,差异有统计学意义(P<0.05)。荧光染色显示模型组小鼠平滑肌细胞脂质水平明显高于实验组细胞,差异有统计学意义(P<0.05)。模型组小鼠主动脉壁可见红色脂肪性板块数量较实验组明显减少,差异有统计学意义(P<0.05)。与模型组小鼠比较,实验组小鼠血脂TC、TG、LDL和HDL均显著下降,差异有统计学意义(P<0.05)。与模型组比较,实验组小鼠血清和平滑肌细胞培养上清炎症因子TNF-α、IL-6和IL-1β的水平,差异有统计学意义(P<0.05)。结论:雷帕霉素显著提高主动脉平滑肌细胞自噬水平,促进平滑肌细胞内部脂质代谢,进而降低了主动脉血管病变以及炎症因子释放,缓解了动脉粥样硬化的发生。

Objective: To explore the therapeutic effect and mechanism of rapamycin on atherosclerotic mice. Methods: 30 Apo E deficient mice were fed with high fat diet to establish atherosclerosis (AS) model.After successful modeling,mice were randomly divided into control group and experimental group.The experimental group was injected with rapamycin 10 mg/kg via caudal vein,and the control group was injected with normal saline of equal volume.After one week of treatment,the mice were sacrificed,the serum were collected and primary aortic smooth muscle cells and cultured.The autophagy level and lipid level of aortic smooth muscle cells was analyzed by immunofluorescence.The levels of blood lipid in each group of mice were analyzed by automatic biochemical analyzer.The pathological changes of aorta were analyzed by HE staining and the peripheral blood inflammation (TNF-α,IL-6 and IL-1β) was detected by ELISA. Results: Compared with the model group,the number of autophagosome of aortic smooth muscle cells in the experimental group increased significantly ( P <0.05).Fluorescence staining showed that the level of lipid in the model group was significantly higher than that in the experimental group ( P <0.05).The number of red adipose plates in aorta wall of model group was significantly lower than that of experimental group ( P <0.05).Compared with the model group,the TC,TG,LDL and HDL in the experimental group decreased significantly ( P <0.05).Compared with the model group,the levels of TNF-α,IL-6 and IL-1β in serum and culture supernatant of aortic smooth muscle cells of the experimental group significantly decreased ( P <0.05). Conclusion: Rapamycin can significantly increase the autophagy level of aortic smooth muscle cells,promote lipid metabolism in the smooth muscle cells,and then reduce aortic vascular disease and inflammatory factors release,alleviate the occurrence of atherosclerosis.