Study On The Prevention And Treatment Of Burdock Inulin On Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease(NAFLD)refers to a clinicopathological syndrome characterized by liver cell steatosis and lipid deposition except alcohol and other definite liver damage factors.In China,the prevalence rate among adults in affluent regions is around 15%and it has been the second most common chronic liver disease.Today the biological activity of natural polysaccharides is a hot topic in the study of NAFLD.Burdock(Arctium lappa L.)is a biennial herb in the composite family widely distributed in Asia and Europe.Burdock inulin(BFO)which extracted from its root is a single homogeneous component with inulin molecular configuration and a molecular weight of 2000-5000Da,the effect of BFO on NAFLD has not been studied.Therefore,in this paper,two different diets,namely a high-fat diet(HFD)and a methionine-choline deficiency diet(MCD),were used to construct NAFLD mice model,and the preventive and therapeutic effects of BFO on NAFLD were studied under different modeling methods.1.Regulation of BFO on intestinal flora of NAFLD mice induced by HFDIn this experiment,the mice used the principle of free access to food and water.After 16 weeks of HFD,the NAFLD mice model was established.After oral BFO for four weeks,the relevant biochemical indicators were measured,by means of liver pathological sections,analysis of gut microbes by 16S rDNA amplicon sequencing to evaluate the therapeutic effects of BFO on NAFLD.The results showed that BFO could significantly reduce the obesity of mice as well as the liver weight and liver index caused by HFD.Also,treatment with BFO significantly decreased the serum TG,TC,LDL-C and increased the HDL-C level,improved liver cell arrangement and distribution,reduced lipid droplet accumulation,down-regulated the expression of lipid metabolism genes Fasn and SREBP-lc in the liver.Moreover,Beta Diversity,PCoA,Tax4Fun PCA of 16S rDNA amplicon sequencing analysis showed that BFO could significantly regulate the structure and function of intestinal flora,improve the relative abundance of Bacteroidetes,Firmicutes and Proteobacteria at phylum level,decrease the ratio of Firmicutes/Bacteroidetes caused by obesity,reduce the relative abundance of Dubosiella and Lactobacillus as well as increase Faecalibaculum at genus level,accordingly alleviate intestinal microecological disorders caused by HFD.2.Study of BFO on lipidomics from NAFLD mice induced by MCDMCD-induced NAFLD mice model revealed that BFO could significantly reduce the weight loss of NAFLD mice as well as their liver weight and liver index.After treatment with BFO,the abnormal elevation of ALT and AST level in serum which reflect liver injury could be obviously lowered,in the meantime,the liver morphology was improved,HE and oil red O stained sections reflected that BFO could notably reduce intercellular adipose hollow space,make liver cells tightly arranged,reduce lipid droplet distribution,inhibit lipid deposition and relieve hepatic steatosis.What's more,BFO could increase the length of the colon of NAFLD mice,making its appearance more similar to normal mice.Widely-targeted lipidomics analysis showed that MCD induced the alteration of hepatic metabolites,among them,295 significantly different metabolites were noted,113 were down-regulated and 182 were up-regulated,while BFO could regulate the lipid metabolic disorder and down-regulated 156 metabolites,reduced the abnormality of most lipid metabolites,including eicosanoid,phosphatidylglycerol,cholesterol ester,ceramide,diglyceride,monoglyceride,sphingomyelin,triglyceride and free fatty acids,etc.What's more,BFO could regulate the expression of metabolites which enriched in metabolic pathways such as glycerolipid metabolism,insulin resistance,regulation of lipolysis in adipocytes,vitamin digestion and absorption,cholesterol metabolism as well as fat digestion and absorption.To sum up,BFO could significantly improve NAFLD which induced by HFD or MCD,and regulate intestinal flora and hepatic lipid metabolism disorders.This study had certain reference significance for the treatment of liver metabolic diseases with natural polysaccharides,and provided basic data support for BFO as a potential treatment for NAFLD.