| NAFLD represents the hepatic manifestation of metabolic syndrome,its characteristic is in the body without large amounts of alcohol consumption on the premise of the abnormal accumulation of fat in one's liver.The number of patients with NAFLD has increased rapidly in recent years as obesity rates have increased.Despite advances in this field of studies,the pathogenesis of NAFLD is complex and there is still no effective therapeutic drug.Tea is a well-known heathy beverage,and the effects of tea polyphenols and catechin monomers on alleviating metabolic syndrome such as obesity and NAFLD have been frequently reported.However,due to the low bioavailability and ambugious molecular targets of tea polyphenols,the underlying mechanisms of health benefits of tea were largely unknown.Based on our previous studies,C57BL/6 mice fed on a high-fat diet were selected to explore the alterations of intestinal barrier function by EGCG intervention using transcriptome sequencing technology in the present study,and the role of intestinal immune barrier in alleviating NAFLD was also preliminarily clarified.Specifically,a total of 36 male C57BL/6 mice(6-week-old)were randomly divided into three groups: low fat diet group(LF,n=12),high fat western diet group(HFW,n=12)and high fat western diet plus EGCG supplementation group(HFWE,n=12)and fed for 14 weeks.Through the induction of high fat diet EGCG intervention obese mice glucolipid metabolic disorders,serum inflammatory reaction and the improvement of fatty liver disease in the result analysis,and explores the dietary EGCG transcriptome sequencing technology intervention effects on NAFLD animal intestinal mucosal immune function,preliminary parsing the EGCG improve intestinal immune barrier in mice and the mechanism of action of NAFLD.The main results are as follows:1.Dietary EGCG intervention significantly inhibits fatty induced obese mice weight gain excessive body fat deposition and lipid levels,significantly improve the obese animals fasting blood glucose level and glucose tolerance ability also significantly reduced the mice serum bacterial lipopolysaccharide(LPS),tumor necrosis factor alpha(TNF alpha)and the concentration of interleukin 6(IL-6).2.Dietary EGCG intervention can reduce the levels of total lipids,TG and TC in the liver and alleviate the accumulation of lipids in the liver.It can also reduce the m RNA expression levels of the inflammatory factors TNF-?,MMP-3 and COX-2 in the liver and alleviate the inflammatory response in the liver caused by long-term high-fat diet.3.The changes of intestinal gene expression profile in EGCG treated mice were further investigated using transcriptome sequencing technology.The differential genes in LF-VS-HFW and HFW-VS-HFWE were screened,which were concentrated in the genes related to intestinal immune function.Based on the changes of inflammatory indicators in blood and liver of mice and the results of KEGG pathway analysis of differentially expressed genes,we focused on the expression of key genes in intestinal Ig A generating immune network and B cell receptor signaling pathway,and used real-time fluorescence quantitative PCR(RT-q PCR)for verification.Compared with HFW group,the expression levels of LBP,TRL-4,APRIL,BAFF,TGF-?,F4/80,CD11 b,CD11c,CD80,CD86,CD163 and MHC-II genes in HFWE group were significantly down-regulated at the m RNA level,and the change trend is the same as LF group..In summary,our results clearly demonstrated the effects of dietary EGCG on preventing the developments of systemic inflammation and NAFLD in mice fed a high fat diet.Simultaneously,EGCG is involved in the regulation of intestinal barrier antigen presenting pathways and Ig A production pathways to significantly ameliorated the intestinal immune homeostasis,which played vital roles in blocking pathogenic microorganisms into circulations.However,the interactions among EGCG,gut flora and intestinal immune system and its role in alleviating NAFLD need to be further clarified. |
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