ABSTRACT
ObjectiveTo explore the mechanism of Huangqisan （HQS） in regulating autophagy to alleviate hepatic steatosis and improve non-alcoholic fatty liver disease （NAFLD） based on adenosine 5'-monophosphate-activated protein kinase （AMPK）/mammalian target of rapamycin （mTOR） signaling pathway. MethodThe main chemical components and targets of HQS and NAFLD-related targets were collected from database and the intersection targets were used for Gene Ontology （GO） functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis. The protein-protein interaction （PPI） network was constructed， and in vivo experimental verification was conducted. Sixty C57BL/6J male mice were randomly divided into normal control group （NCD）， model group high-fat diet （HFD）， metformin group （MET， 0.25 g·kg-1）， low-dose Huangqisan group （HQS-L， 0.5 g·kg-1）， and the high-dose Huangqisan group （HQS-H， 1 g·kg-1）， with 12 mice in each group after a one-week acclimatization period. NAFLD model was induced by HFD， and intragastric administration was performed at the same time， once a day for 13 weeks. Random blood glucose， serum total cholesterol （TC）， triglyceride （TG）， non-esterified fatty acid （NEFA）， low density lipoprotein-chdesterol （LDL-C） levels， and liver TG content were determined. The liver weight was weighed， and liver index was calculated. Hematoxylin-eosin （HE） staining， oil red O staining， transmission electron microscope （TEM）， real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and Western blot were used to verify the effect and reveal the potential mechanism of C57BL/6J mice in vivo. ResultThrough network pharmacology analysis， combined with previous studies， it was predicted that HQS may improve NAFLD by regulating autophagy via the AMPK/mTOR signaling pathway. The result of in vivo experiment showed that， as compared with NCD group， random blood glucose， body weight， serum TC， LDL-C， NEFA， liver weight， liver index， and liver TG content of mice in the HFD groups were significantly increased （P<0.01）. HE staining showed massive lipid droplets （LDs） vacuolated， oil red O staining showed lipid accumulation in liver cells， and no obvious autophagosomes and autolysosome were observed under TEM. The relative mRNA expression of LC3A、LC3B、AMPKα1 and protein expression of AMPK， phosphory phosphorylated（p）-AMPK， and p-AMPK/AMPK were significantly down-regulated （P<0.01）， while the protein expression of microtubule-associated protein 1 light chain 3 （LC3）Ⅱ/Ⅰ and p-mTOR was significantly up-regulated （P<0.01）. As compared with HFD groups， liver weight， serum TG， and NEFA levels in HQS-L and HQS-H groups were significantly deceased （P<0.05， P<0.01）. HE staining and oil red O staining showed the improvement of liver pathological changes after HQS administration. Under TEM， a small amount of autophagosome and autolysosome were observed. Besides， liver index was significantly decreased in the HQS-L group （P<0.01）， and random blood glucose， serum TC level and liver TG content were significantly decreased in the HQS-H group （P<0.05）. The results of Western blot and Real-time PCR showed that the mRNA expression of LC3A and LC3B and the protein expression of LC3Ⅱ/Ⅰ， p-AMPK， and p-AMPK/AMPK were significantly up-regulated （P<0.01）， while the mRNA expressions of p62 and protein expression of p62 and p-mTOR were significantly down-regulated （P<0.05， P<0.01）. ConclusionHQS may promote autophagy and restore autophagy flux via the AMPK/mTOR signaling pathway to alleviate hepatic steatosis improving NAFLD.