The Intervention Of Mytilus Edulis Extract On Food-Induced Systemic Low-Grade Inflammation Based On Intestinal Flora

Systemic low-grade inflammation can lead to a variety of serious chronic diseases.Litchi,as a representative of "heating" food,is easy to cause "overheated" inflammation,but its pathway and target are not clear.As the existing synthetic chemical anti-inflammatory drugs have obvious adverse reactions,and the anti-inflammatory active substances from natural Marine sources have the advantages of meeting the practical needs and having fewer side effects,it is urgent to find new anti-inflammatory substances from Marine sources.Intestinal flora disorder is an important driving force to induce a variety of chronic low-grade inflammatory diseases.In this study,we constructed a human flora-associated mouse(HFA)model of intestinal flora by insufflating fecal bacterial suspension of volunteers in mice.The mouse model of systemic low degree inflammation was established by high dose litchi screened by gavaging.Mytilus edulis(ME)were treated with different doses.By measuring serum levels of inflammatory factors,intestinal flora structure and function,and intestinal mucosal barrier integrity.The effect of excessive consumption of litchi on the function and structure of the flora and the mechanism of inflammation were investigated.The results are as follows:1.The construction of a human flora-associated mouse(HFA)model of intestinal flora can simulate the intestinal flora of volunteers to a certain extent.The composition and structure of intestinal flora in mice could be changed to a certain extent by inoculating fecal bacterial suspension of mice volunteers,and the intestinal flora of mice could be similar to that of volunteers selected in the experiment.The proportion of intestinal flora in the model group was significantly closer to that of the volunteers.In UPGMA clustering analysis,the horizontal groups can be grouped into one group.At the species level,21 unique strains of the volunteer group were detected in the model group,indicating that the multi-species humanized strains successfully colonized the intestinal tract of the model mice.The above results indicated that the humanized mouse model of intestinal flora was successfully constructed,which to some extent simulated the intestinal flora of the volunteers.2.High-dose litchi changes the integrity of intestinal barrier by causing bacterial disturbance,leading to low-degree inflammation of the system.The levels of TNF-? in serum,a typical pro-inflammatory factor,were significantly increased after the mice received a high dose of litchi extract,which was more than 2 timesthat of the control group,indicating that sustained high dose of litchi could cause immune imbalance in the mouse body and produce systemic and systemic low level inflammation,and the mouse model of food-induced inflammation was successfully constructed.The intervention of medium and high dose litchi significantly increased the species richness in the intestinal tract of mice.The difference of different dose groups was significant,but the difference between different dose groups was not significant.litchi intervention at the phylum level had a significant effect on the abundance ratio of intestinal flora in mice.The abundance of Fusobacteria decreased significantly at high dose.At the genus level,the abundance of Phascolarctobacterium,Akkermansia and Lactobacillus decreased significantly in each dose group after litchi intervention,while the abundance of Prevotella and Bacteroidetes increased significantly.Compared with the low-medium dose group,the abundance of Megamonas decreased by 99.32 times and that of Bilophila increased by 3.43 times.The results showed that Fusobacteria,Megamonas and Bilophila were significantly different between the high-dose group and the low-dose group.Therefore,Fusobacteria,Megamonas and Bilophila may be the key drivers of systemic low-grade inflammation induced by excessive consumption of litchi.Medium and high dose litchi intervention leads to the increase of intestinal epithelial cell junction complex,the proliferation of intestinal recess,and goblet cell depletion,which represent the characteristics of weakened intestinal mucosal barrier,and can lead to the increase of intestinal permeability and the entry of LPS into the blood,thus causing low degree of systemic inflammation.3.High-dose ME inhibited litchi-induced systemic low-grade inflammation by repairing the structural integrity of the barrier.The inflammatory marker TNF-? in the serum of the inflammatory model mice was significantly reduced to the level of the control group after the medium and high dose of ME,indicating that the medium and high dose of ME significantly alleviated and reduced the systemic low-grade inflammation induced by food.ME extract can restore the healthy state of mice by restoring the bacterial diversity of inflammatory model mice and the abundance ratio of inflammatory driving bacteria,Megamonas and Bilophila,thereby reducing the intestinal barrier permeability,preventing LPS from entering the blood,and reducing the level of inflammatory factors in the body.