目的 研究miR-199a-3p对高脂饮食诱导的非酒精性脂肪性肝病( non-alcoholic fatty liver disease,NAFLD)模型小鼠肝脏脂肪变性的影响.方法 40只雄性C57BL/6J小鼠适应性喂养7 d,然后随机分成4组,正常对照组10只饲喂标准饲料(SCD),模型组10只饲喂高脂饮食(HFD),喂养8周后收集肝组织.另外,在2组饲喂HFD的小鼠(每组10只)通过尾静脉静脉注射腺病毒,使用腺病毒载体作为对照(Ad-Ctrl组)与表达miR-199a-3p(Ad-199a组)的腺病毒载体进行比较. 2周后收集肝脏.进行油红O染色观察肝脏组织学病理改变;测量肝脏TG含量;PCR测量肝脏miRNA、FASN、SREBP1 mRNA的表达.结果 在SCD组和HFD组小鼠肝脏中检测到6种下调miRNA.与SCD组小鼠相比,除miR-145-5p外,HFD组小鼠中检测到的miRNA均显著下调.同时, miR-199a-3p具有显著倍数变化(P<0. 001).与Ad-Ctrl组相比,Ad-199a组肝脏质量显著减轻(P<0. 05);Ad-199a组肝脏质量/体质量值显著下降(P<0. 01);Ad-199a组肝脏TG含量明显降低(P<0. 01);油红O染色结果显示,SCD组、Ad-199a组未见明显的脂滴沉积;而HFD组及Ad-Ctrl组则见到大量大小不一的红色脂滴沉积.与Ad-Ctrl组相比,Ad-199a组肝脏内miR-199a-3p的表达量显著提高(P<0.01);脂肪合成酶基因(FASN)显著减少(P<0. 001);固醇调节元件结合蛋白(SREBP1)显著降低(P<0. 01).结论 miRNA-199a-3p在肝脏中表达下调,在肝脏脂肪形成过程中有明显抑制作用,可以作为治疗NAFLD潜在治疗靶点,但其具体机制需进一步研究.%Objective To study the effect of miR-199a-3p on hepatic steatosis induced by high-fat diet in non-alcoholic fatty liver disease(NAFLD) model mice. Methods A total of 40 male C57BL/6J mice were fed adaptively for 7 days and then randomly divided into 4 groups. Normal control group (n=10) received standard diet (SCD), and the model group (n=10) fed with high fat diet (HFD) and harvested liver tissue after 8 weeks of feeding. In addition, two groups of HFD diets (10 mice in each group) were intravenously injected with adenovirus via tail vein, the adenovirus vector was used as a control (Ad-Ctrl group) compared with the adenovirus vector expressing miR-199a-3p (Ad-199a group). The liver tissues after two weeks were collected. Oil red O staining was used to observe the histopathological changes of liver; liver TG content was measured; PCR was used to detect the expressions of liver miRNA, FASN and SREBP1 mRNA. Results Six down-regulated miRNAs were detected in the liver of SCD and HFD mice. Compared with SCD mice, all miRNAs detec-ted in HFD mice were significantly down-regulated with the exception of miR-145-5p. Meanwhile, miR-199a-3p had a significant fold change (P<0. 001). Compared with Ad-Ctrl group, the liver mass of Ad-199a group was significantly reduced ( P<0. 05) ; the liver mass/body mass ratio of Ad-199a group was significantly decreased ( P<0. 01) ; the TG content of Ad-199a group was significantly decreased. Red O staining showed that there was no obvious lipid droplet deposition in SCD group and Ad-199a group, while a large number of red lipid droplets were observed in HFD group and Ad-Ctrl group. Compared with the Ad-Ctrl group, the expression of miR-199a-3p in the liver of Ad-199a group was sig-nificantly increased ( P<0. 01) ; FASN was significantly reduced ( P<0. 001) ; the sterol regulatory element binding protein (SREBP1) was significantly lower (P<0. 01). Conclusion The down-regulation of miRNA-199a-3p in the liver and the inhibition of hepatic adipogenesis can be used as potential therapeutic targets for the treatment of NAFLD. How-ever, its specific mechanism needs further study.
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