Effect Of EGCG On Gut Microbiota Diversity And Fat Deposition In KM Mice

The intestinal flora is thought to be associated with a variety of diseases,so how to regulate the intestinal flora has become a major research focus.The study found that there are many factors that affect the composition and function of intestinal flora,such as diet,antibiotics,host genotypes,probiotics and diseases,among which the diet has the greatest impact on the intestinal flora.In this study,a human Kunming(KM)mouse model was used to establish a human-associated(HFA)mouse model.The model can simulate human intestinal flora to a certain extent.The system also avoids the ethical limitations and other issues that directly use humans for the study of intestinal flora.On this basis,on the one hand,two different diets were used to intervene in HFA mice and fecal samples were collected on the first,second,and fourth weeks for 16 S rRNA sequencing,and the effects of different diets on colonization of HFA mice were found.On the other hand,it studies the regulation effect of EGCG,which is the main functional substance of tea polyphenols,on obesity and intestinal flora,providing a theoretical basis for the study of tea function.The specific experimental results are as follows:Firstly,sterile mice were gavaged with healthy human feces,and the intestinal flora of HFA mice was intervened with both roughage and purified feed.After 4 weeks of colonization,according to the results of 16 sRNA sequencing,PcoA and UDPMG cluster analysis revealed roughage and purified feeds.After the treatment,the intestinal microflora changed significantly,and the human feces and roughage colonization were concentrated on the upper side at different stages of the colonization.Purified feed colonization was concentrated at the lower side during the different stages of the colonization,indicating that there was a large difference between the groups,suggesting possible dietary conditions for the intestinal bacteria The group structure has a certain influence.At the same time,the human feces was closer to the roughage group,suggesting that the gut microbiota in colonized humans may be more similar to the human fecal intestinal flora.Next,the constructed HFA models were randomly divided into two groups: 40 in the high-fat group and 10 in the normal group.They were fed with high-fat diet and common feed respectively.After 8 weeks,they were sacrificed and 10 mice were weighed.Weight,weight of epididymal fat pads,blood glucose and lipids,hematoxylin-eosin(HE)staining of hepatic and epididymal fat pads,and 16 S rRNA sequencing analysis of fecal bacteria.The obtained obese mice were randomly divided into three groups: the control group,the low-dose 0.2% EGCG group and the high-dose 0.8% EGCG group.The animals were fed the common feed and all were sacrificed after 8 weeks.The same index as above was measured.The results showed that the weight of epididymal fat pad,total cholesterol(Tch),and low density lipoprotein cholesterol(LDL-C)were significantly lower in the high-dose group than in the control group(p<0.05).At the same time,the fat cell size was also significantly greater than that of the control group.Decreased(p<0.01).In addition,liver lesions in the EGCG intervention group were significantly better than those in the control group and showed a dose-effect relationship.This confirmed that EGCG has a certain effect on lipid-lowering and hepatic injury repair in obese HFA mice.In addition,16 sRNA sequencing of intestinal flora,PcoA,UDPMG cluster analysis found that high-fat diet changed the intestinal flora.From the door level analysis,the percentage of thick-walled bacteria in the high-fat group was(82.1±3.137)% higher than that of the common group(68.07±4.857)%,which was 20.6%,and that of the bacillus(10.14±2.294)%.The proportion of Bacteroidetes in the general group(23.18±4.479)% was reduced by 60.9%.In addition,after 8 weeks of EGCG intervention,EGCG also significantly altered the intestinal microflora structure of obese mice.Compared with the control group,Peptostreptococcaceae and Romboutsia bacteria were significantly increased after treatment with high-dose EGCG.The EGCG-treated group had lower abundance of the thick-walled bacterium compared with the control group,and the abundance of Bacteroidetes was higher than that of the control group.