Effect Of Polysaccharide Of ACP On Lipid Metabolism And Its Intestinal Flora In Hypercholesterolemic Mice

In this study,Auricularia cornea var.Li.polysaccharides(ACP)was extracted and purified from agaric fungus in Changchun,Jilin,China.The structure of ACP was initially identified;a hypercholesterolemic mouse model was established to study the effects of ACP on the serum biochemical indexes and liver histopathological sections of hypercholesterolemic mice.Based on lipomics and intestinal microbiomics,the intervention effect of ACP on hypercholesterolemic mice was further evaluated.The effects of ACP intervention on lipid metabolism and intestinal microflora in hypercholesterolemic mice were elaborated,and the correlation between four items of blood lipids and changes in intestinal microflora after ACP intervention was explored.Methods:(1)Water-soluble ACP were extracted by aqueous extraction and alcoholic precipitation,and the extraction rate and polysaccharide content were determined,and characterized to identify the structure and monosaccharide composition.(2)Thirty male C57BL/6J mice,a hypercholesterolemic model,were divided into five groups of six mice each and fed a high-fat hypercholesterolemic diet with 60% fat to energy ratio and ingested ACP solution at concentrations of 400 mg/kg,200 mg/kg,100mg/kg and 20 mg/(kg·d)of simvastatin solution by gavage,respectively.The effects of ACP intervention on lipid metabolism in hypercholesterolemic mice were investigated by comparing body weight,organ coefficients,serum TC,TG,HDL-C,LDL-C,hepatic AST and ALT contents,oxidative stress indexes and changes in fatty acid composition in different groups of mice.(3)The high-throughput sequencing of the V3+V4 region of the gene was performed on the intestinal content sample of the experimental mice by 16 S r DNA sequencing.Through the Alpha and Beta diversity analysis of intestinal microorganisms,the differences in microbial diversity and abundance among the KB,HFD and ACPH groups were studied,and Spearman analyzed and studied the correlation between the marker species and blood lipid four items among different groups,and conducted joint analysis on lipid metabolism and intestinal microorganisms to investigate the effect of ACP intervention on intestinal flora in hypercholesterolemic mice.Results:(1)The content of ACP was 89.19%,ACP structure: polysaccharide withβ-glycosidic bond with pyran conformation.Main components of ACP: glucose;xylose;mannose;galactose;fructose.(2)After five weeks of intervention with high,medium,and low doses of ACP in hypercholesterolemic mice,combined with the biochemical indicators of the mice,ACP can reduce the content of TC and LDL-C in the serum of hypercholesterolemic mice to varying degrees,increase the content of HDL-C(p<0.05),increase the activity of SOD and GSH in the liver of the mice(p<0.05),and reduce the content of MDA(p<0.05),with a certain dose effect.The ACPH group showed the best cholesterol lowering effect among the three intervention groups.(3)The liver sections of hypercholesterolemic mice showed structural deformation and hepatocyte damage with swelling and inflammatory infiltration.After ACP intervention,the morphological structure of these tissues was normalized,and the symptoms of intertissue edema and cellular inflammation were all improved to some extent.As the concentration of ACP increased,the morphological structure of liver tissue cells became closer to that of the KB group,indicating that the ACPH group showed the most excellent effect of alleviating liver injury and inflammation among the three groups of intervention.(4)A total of 10 fatty acids were identified in the livers of hypercholesterolemic mice.Compared with the HFD group,the ACP intervention group showed a significant decrease in MUFA content and a significant increase in PUFA content.As the concentration of ACP increased,the changes of liver fatty acids were more obvious compared with the HFD group,indicating that ACP has an effect on liver fatty acid metabolism in hypercholesterolemic mice and has a dose-effect relationship.(5)The distribution of bacteria in the intestinal contents of each group of mice was analyzed by 16 S r DNA sequencing.Ace index and Shannon index were increased in the ACP intervention group compared with the HFD group,indicating that the diversity and abundance of the intestinal microbiome of hypercholesterolemic mice were significantly increased after ACP intervention.ACP increased the abundance of beneficial bacteria in the intestine by elevating the abundance of the beneficial genera Blautia,Lactobacillus,promoting the reproduction of beneficial bacteria and decreasing the relative abundance of harmful bacteria such as Proteobacteria,Faecalitalea,Lachnospiraceae and Lachnoclostridium to improve the dysbiosis of intestinal microbiota in hypercholesterolemic mice,thus reducing the probability of obesity metabolic diseases in the organism.(6)In this study,we found that the diversity of harmful bacteria such as Erysipelatoclostridium,Faecalitalea,UBA1819,Ruminococcus,Streptococcus,Family＿XIII＿AD3011＿group was increased in the highcholesterol mice compared to normal mice and was positively correlated with TC,TG,and LDL-C,while negatively correlated with HDL-C(p< 0.05).After ACP intervention,was able to decrease the abundance and diversity of harmful bacteria such as Erysipelatoclostridiaceae,Clostridium＿sensu＿stricto＿3,Peptostreptococcaceae,increased the abundance of beneficial bacteria such as Romboutsia,Blautia,and were negatively correlated with TC,TG,LDL-C and positively correlated with HDL-C(p< 0.05).The above indicates that high dose of ACP intervention has a modulating effect on lipid metabolism in hypercholesterolemic mice and can improve the intestinal flora structure of hypercholesterolemic mice to some extent.