Research On The Mechanism And Treatment Of Gastritis In C57BL/6 Mice Induced By High Salt Diet

Background and objectiveGastritis is an inflammatory disease of gastric mucosa caused by various factors,and it is one of the most common digestive diseases of which the incidence continues to increase.Therefore,it is necessary to explore the pathogenesis of gastritis and treatment measures.Gastritis can be induced by a variety of factors such as non-steroidal drugs,mental stress,and Helicobacter pylori infection.Bad eating habit is another major factor of gastritis.Recent studies have found that high salt diet is a key factor to induce gastritis.The incidence of gastric cancer in southern and northern China is very different.In the north,it is 2-3 times higher than that in the south.The incidence of gastritis in the North is as high as 40%,which is positively correlated with the high salt diet.However,the mechanism of high salt diet induced gastritis is unknown.There are many kinds of bacteria colonization in the human gastric mucosa,and the stomach microbiota is relatively stable in the stomach.Gastro-intestinal microbes change with diet,resulting in temporary or sustained changes in the gastro-intestinal microbiota.High salt diet can aggravate colitis in mice by inducing microbiota disorder.In addition,clinical trials have also proved that high salt diet can change the human intestinal microbiota and cause disease.However,whether a high salt diet can cause stomach diseases by changing the gastric microbiota remains to be researched.The gastric microbiota can not only participate in metabolism,alimentation,promotion of gastro-mtestinal development,but also regulate the body's immune response.Gastric microbiota disturbance induced by high salt diet may have a significant effect on the host's immune system.Microbial dysregulation can trigger gastritis by inducing differentiation of Th17 cells in adjacent or distant sites.The main purpose of this research is to study whether the high salt diet leads to gastritis caused by the increasing of Th17 cells induced by the disorder of the gastric microbiota,to fnd a way to treat gastritis,and to provide a new idea for clinical treatment of gastritis.Materials and Methods1.Construction of a gastritis model of C57BL/6 mice induced by high salt diet.H&E staining was used 'to detect the degree of gastritis.The expression of inflammatory cytokines such as IL-6,IL-18 and IL-1? in the stomach of mice was detected by ELISA.2.The DNA of the mouse gastric microbiota was extracted for 16SrRNA sequencing and bioinformatics analysis was performed.3.The number of Th17 cells in the spleen of mice was detected by flow cytometry.The expression of cytokines related to Th17 cells such as IL-6,IL-17A and TGF-?in the stomach of mice was detected by ELISA.4.The content of ILA in the stomach of mice was measured by ELISA.5.Through statistical analysis of the gastric microbiota,we identified six genera,and determined the relationship between these bacteria and gastritis and Th17 cells by Spearman correlation analysis.6.Predicting the function of the microbiota by PICRUSt.7.Based on the results predicted by PICRUSt,a model for the treatment of gastritis in mice treated with buckwheat was constructed.Detecting the degree of gastritis;analyzing changes:in the gastric microbiota and detect the number of Th17 cells.Result1.High salt diet induced gastritis in mice:H&E staining and histological scores showed that the degree of gastritis in the high-salt diet group was significantly higher than that in the control group.In addition,The ELISA test showed that the inflammatory cytokines such as IL-18 and IL-1? in the stomach of the high-salt diet mice increased significantly.This suggests that high salt diet can induce gastritis in mice2.High salt diet induces microbiota disorder:The 16SrRNA sequencing technology and bioinformatics analysis found that the high salt diet caused disorder in the stomach of mice.Compared with the control group,the diversity of gastric microbiota in the high salt diet group were significantly changed,as well as the relative abundance of bacteria.The number of the phylum of Bacteroides and Proteobacteria were reduced in the high salt diet group,while the Firmicutes in the high salt diet group was significantly increased,;At the genus level,the relative abundance of Unclassified S24-7?Lactobacillus were decreased,and the relative abundance of Unclassified Clostridiales?Unclassified_Lachnospiraceae was increased3.High salt diet promotes Th17 cell differentiation:compared with the control group,the Thl7 cells in the high salt diet group increased significantly;IL-6,TGF-?,IL-17A were significantly increased.Furthermore,the ILA of gastric tissue was significantly decreased in the high salt diet group.Six bacterial genus are found to be correlate with the degree of gastritis and the number of Thl7 in mice by Spearman Correlation Analysis.4.Buckwheat can regulate microbiota disorder and treat gastritis:H&E staining and histological scores showed that the degree of gastritis in treated group was significantly reduced,and inflammatory cytokines such as IL-6 and IL-1? were significantly decreased.Flow cytometry showed that the Th17 cells in the treated group were significantly reduced.Compared with the high-salt diet group,the a diversity and ? diversity of the mice in the treatment group were similar to those in the control group.In addition,after feeding buckwheat,,the relative abundance of the other five bacteria except the Lactobacillus changed by the high-salt diet was similar to the control group.Therefore,buckwheat can improve the microbiota disorder caused by high salt diet and regulate the metabolism of the gastric microbiota.ConclusionHigh salt diet can induce gastritis in mice,change the microbiota situation in the stomach of mice,and cause the microbiota disorder.The high salt diet reduces the relative abundance of Lactobacillus,and the ability of mice to synthesize ILA by tryptophan is reduced,thereby reducing the inhibition of Th17 cells,and then the proliferation of Th17 cells will lead to gastritis.Buckwheat is a kind of crop rich in polysaccharide and tryptophan.It also has the effect of anti-inflammatory and reducing hypertension.According to PICRUSt,we used buckwheat to construct a treatment model.It was found that the content of ILA increased,Th17 cells decreased,and the gastritis is relieved.In conclusion,buckwheat can regulate the microbiota and treat gastritis.