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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(P<0.05),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(P<0.05);血浆AGEs的含量显著降低(P<0.05);机体的抗氧化功能有所提升,血浆MDA的含量显著减少(P<0.05),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(P<0.05)。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。
Objective: To investigate the effect and mechanism of phytosterol ester on aging of aorta in rats. Methods: Forty-two 12-month-old female Sprague-Dawley rats were randomly divided into control group, model group and phytosterol ester group. The rats were fed with basal diet, high fat diet and high fat plus 2% phytosterol ester (W / W) Feed 6 months. The paraffin sections of the aorta were stained by HE staining and Masson staining. The pathological changes of the aortic tissue were observed. The absolute area of the vascular smooth muscle cells and collagen fibers was analyzed. The contents of plasma lipid, advanced glycation end products (AGEs) and malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and catalase (CAT) were measured. The mRNA and protein levels of SIRT1 and PPARγ in aortic tissues were evaluated by real-time PCR and Western blot respectively. Results: Compared with the model group, the levels of total cholesterol and low density lipoprotein cholesterol in the phytosterol ester group were significantly decreased (P <0.05), while the triglyceride levels were not significantly different ; The aortic intima and media thickening and smooth muscle cell migration were improved; the content of aortic smooth muscle cells and collagen fibers was significantly decreased (P <0.05); the content of AGEs in plasma was significantly decreased (P <0.05) (P <0.05). There was no significant difference in the activity of SOD and CAT between the two groups. The expression of PPARγ was down-regulated and the expression of SIRT1 was up-regulated (P <0.05). Conclusion: Phytosterol esters can delay the aging of the aorta in rats. Its mechanism may be related to reducing the formation of reactive oxygen species. Phytosterol esters may play a role by activating SIRT1 or inhibiting the expression of PPARγ.