植物甾醇酯对大鼠主动脉衰老及相关基因表达的影响

目的:探讨植物甾醇酯延缓大鼠主动脉衰老的作用及其机制。方法:将42只12月龄雌性SD大鼠随机均分为对照组、模型组和植物甾醇酯干预组,分别喂食基础饲料、高脂饲料和高脂加2%植物甾醇酯(W/W)饲料6个月。采用HE染色法和Masson染色法对主动脉横截面石蜡切片进行染色,观察主动脉组织的病理学改变,对血管壁平滑肌细胞和胶原纤维的绝对面积进行图像分析。检测血浆脂质蛋白、晚期糖基化终末产物(AGEs)、丙二醛(MDA)的含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的活性。分别采用real-time PCR和Western blot的方法评估主动脉组织沉默信息调节因子1(SIRT1)和过氧化物酶体增殖物激活受体γ(PPARγ)的mRNA和蛋白表达水平。结果:与模型组相比,植物甾醇酯干预组的血浆总胆固醇和低密度脂蛋白胆固醇水平显著降低,高密度脂蛋白胆固醇的水平相反(P0.05),甘油三酯的水平没有统计学差异;主动脉内膜和中膜的增厚以及平滑肌细胞的迁移均得到改善;主动脉平滑肌细胞和胶原纤维的含量显著下降(P0.05);血浆AGEs的含量显著降低(P0.05);机体的抗氧化功能有所提升,血浆MDA的含量显著减少(P0.05),SOD和CAT活性的差异没有统计学意义;PPARγ的表达下调,SIRT1的表达上调(P0.05)。结论:植物甾醇酯能够延缓大鼠主动脉的衰老。其机制可能与降低机体活性氧的生成有关。植物甾醇酯可能通过激活SIRT1或抑制PPARγ的表达而发挥作用。

Effects of phytosterol ester on aortic aging and expression of related genes in rats

AIM: To explore the protective effect of phytosterol ester (PSE) on aortic aging in rats. METHODS: The female SD rats (12 months old, n=42) were randomly divided into control group, model group and PSE group. During the experiment, the rats in control group, model group and PSE group were treated with basic feed, high-fat diet (HFD) and HFD with 2% PSE (W/W) for 6 months, respectively. The morphological changes of the aorta were observed by HE staining and Masson staining, and the absolute area of smooth muscle cells and collagen fiber in the vascular wall were measured by image analysis. The levels of advanced glycosylation end products (AGEs), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in the plasma were detected. The expression of silent information regulator 1 (SIRT1) and peroxisome proliferator-activated receptor γ (PPARγ) at mRNA and protein levels in the vascular tissue was determined by real time PCR and Western blot, respectively. RESULTS: PSE significantly lowered plasma TC and LDL-C, and increased plasma HDL-C level (P<0.05), but had no effect on plasma TG level. PSE significantly attenuated the thickening of intima and media of aging aortic, and decreased the migration of vascular smooth muscle cells (VSMC) and the amount of VSMC and collagen fiber in the aorta (P<0.05). PSE significantly reduced the contents of AGEs and MDA (P<0.05), but had no effect on the activity of SOD and CAT in the plasma. PSE also down-regulated the expression of PPARγ and up-regulated the expression of SIRT1 (P<0.05). CONCLUSION: PSE is able to attenuate the senescence process in the aorta by reducing the production of reactive oxygen species in plasma, and activating SIRT1, or inhibiting the expression of PPARγ in vascular tissues.