Effects Of High-Fat And High-Salt Diet On Intestinal Microecology And Bile Acid Metabolism

Unhealthy diet habits are closely related to human health.Recently,gut microbiota has attracted much attention in the relationship between diet and health,and has gradually become a research hotspot.It is generally believed that diet affects gut microbiota,and changes in the latter affect metabolism,which in turn affects the intestinal tract and even other organs.The balance of bile acids metabolize are closely related to gut microbiota.Due to the abnormal metabolism of bile acids,many diseases in liver and intestinal tract can be caused.It is of great significance to study the effects of unhealthy diet habits on gut microbiota and bile acid metabolism.It is of great significance to reveal the specific mechanism behind bad eating habits affecting health.Therefore,aiming at the two diet habits of high fat and high pickled vegetables,this study used a mouse model to reveal the effects of bad eating habits on health from the point of view of intestinal microecology and the changes of metabolites such as bile acids.At the same time,as unconjugated bile acids are associated with a variety of diseases,this paper improved the GC-MS method for targeting identification of unconjugated bile acids in rodents to facilitate follow-up research.The full text is divided into three parts: the first part is the establishment of unbound bile acid targeting analysis method.The second is high fat diet,which is divided into control group,high fat diet group and fructo-oligosaccharide group(high fat diet +1.2g/kg/d FOS).The third is the eating habit of high pickled vegetables,which is divided into control group,high salted vegetable diet group and lycopene group(high salted vegetable diet + 20mg/kg/d LP).The mice with two dietary habits were studied by metabonomics,16 S r DNA sequencing and RT-q PCR.The results are as follows:The established GC-MS targeting analysis method has a repetition rate RSD of 2.05%～2.91%,a detection limit of 0.003～0.055 μg/m L,a quantitative limit of 0.009～0.182 μg/m L,a recovery rate of 72.02% and 115%,and a good linearity of the standard curve.High fat diet had an effect on intestinal metabolism in mice,the total bile acids in liver and unconjugated bile acids in faeces increased significantly.At the same time,the structure and composition of gut microbiota changed.In addition,the significant increase of total bile acids in liver and unconjugated bile acids in faeces increased the FXR-FGF15-FGFR4 and FXR-SHP signal pathways.After the intake of FOS,the DCA and unconjugated bile acids proportion of mice in faeces further increased,and enhanced the two signal pathways in hepatointestinal circulation,resulting in intestinal and liver damage.High salted vegetable diet had an effect on intestinal metabolism in mice.The contents of acetic acid,propionic acid and isobutyric acid increased significantly,while butyric acid decreased significantly.DCA in faeces increased significantly,CA and β-MCA in liver increased significantly,while T-α-MCA and T-β-MCA decreased significantly.At the same time,the structure and composition of gut microbiota were changed.High-dose pickled vegetable diet significantly increased the expression of ifn-γ and il-17 a,which are closely related to hypertension,and the expression of il-23 a,tgf-β and other inflammatory factors were significantly increased.Therefore,a high dose of salted vegetables diet may cause high blood pressure,but also cause intestinal inflammation.The intake of LP will alleviate these adverse effects.In summary,on the basis of establishing a GC-MS targeting analysis method of unconjugated bile acids in rodents,this paper analyzed and measured the changes of intestinal metabolism in mouse models with two kinds of dietary habits,and found that both diets would cause some damage to health.However,the intake of FOS may further cause liver damage in mice fed with high-fat diet,and the intake of LP in high-pickled vegetable diet can alleviate hypertension and enteritis to a certain extent,so this study has a certain significance for the selection of active substances in fruits and vegetables in people with unhealthy diet.