SIRT1介导间歇性禁食改善高脂饮食诱导的肥胖小鼠脂肪组织线粒体功能和炎症状态

SIRT1-mediated intermittent fasting improves adipose tissue mitochondrial function and inflammation in high-fat dietinduced obese mice

目的探讨间歇性禁食对高脂饮食诱导的肥胖小鼠白色脂肪组织线粒体功能和炎症状态的影响以及沉默信息调节因子2相关酶1(SIRT1)在其中的作用。方法将5~6周龄雄性C57BL/6小鼠随机分为普通自由饮食组(CD组)、高脂自由饮食组(HFD组)和高脂间歇性禁食组(HFD-IF组,隔日禁食24 h),每组各5只,喂养12周。用HE染色观察各组小鼠白色脂肪组织情况,并检测白色脂肪SIRT1、磷酸化腺苷酸活化蛋白激酶(p-AMPK)、叉头转录因子1(FOXO1)、线粒体功能和炎症相关基因的表达情况。在小鼠尾静脉注射腺相关病毒(AAV)-shSIRT1敲减SIRT1表达,分别给予小鼠高脂自由饮食和高脂间歇性禁食,检测上述指标。结果HE染色结果显示HFD-IF组脂肪细胞体积减小。蛋白免疫印迹结果显示高脂自由饮食时脂肪组织SIRT1、p-AMPK、FOXO1蛋白表达均下调,间歇性禁食后均上调(P均<0.05)。定量PCR结果显示HFD组线粒体功能基因Tfam、Nrf1、Pgc-1a表达下调(P均<0.001),炎症基因TNF-α、单核细胞趋化蛋白1、生长因子样模体黏液样激素样受体表达均上调(P均<0.01),间歇性禁食后线粒体功能相关基因均上调(P均<0.05),炎症相关基因均下调(P均<0.05)。敲减SIRT1后,HFD-IF组的上述指标上调或下降的趋势均有所减弱甚至消失(P均<0.05)。结论SIRT1通过改善小鼠内脏白色脂肪组织线粒体功能和炎症状态从而介导间歇性禁食改善高脂喂养诱导的肥胖。

Objective To investigate the role of SIRT1 in the effect of intermittent fasting on mitochondrial function and inflammation in white adipose tissue(WAT)of obese mice induced by high-fat diet.Methods Male C57BL/6 mice aged 5-6 weeks were randomly divided into the control diet(CD)group(n=5),high‐fat diet(HFD)group(n=5)and high-fat diet intermittent fasting(HFD-IF,alternate-day fasting 24 h)group(n=5)and fed for 12 weeks.The pathological changes of WAT were observed by HE staining.The expression levels of SIRT1,p-AMPK,FOXO1 and mitochondrial function,inflammation-related genes in WAT of each group were detected.AAV-shSIRT1 virus was delivered by tail-vein injection into mice to knockdown SIRT1.HFD and HFD-IF were given.The parameters above were determined.Results HE staining indicated that the adipose cell volume was decreased in the HFD-IF group.Western blot showed that the expression levels of SIRT1,p-AMPK and FOXO1 in adipose tissues were significantly down-regulated in the HFD mice(all P<0.05),which were significantly up-regulated after intermittent fasting(all P<0.05).qPCR revealed that the expression levels of mitochondrial functional genes,including Tfam,Nrf1 and Pgc-1a were dramatically down-regulated in the HFD group(all P<0.001),whereas those of inflammatory markers,such as TNF-α,MCP-1 and F4/80,was significantly up-regulated(all P<0.01).After intermittent fasting,the expression levels of genes related to mitochondrial function were up-regulated(all P<0.05),whereas those of inflammatory markers were down-regulated(all P<0.05).After knockdown of SIRT1,the trend of up-regulating or down-regulating the expression levels of these parameters was weakened or even absent in the HFD-IF group(all P<0.05).Conclusion SIRT1 mediates intermittent fasting in improving high-fat diet-induced obesity via ameliorating adipose tissue mitochondrial function and inflammation.