Study On The Characteristic Of Glucose-lipid Metabolic Disorders In Aged Mice And The Effect And Mechanism Of Tian Huang Formula Based On Liver-gut Axis

Background:The global prevalence of glucolipid metabolic disorders(GLMD)in middle-aged and elderly people is increasing year by year,which result in a great clinical and economic burden to the world.However,the pathogenesis of GLMD in the elderly is not completely clear at present,and there is an urgent need to find ways to prevent and treat glucolipid disorders in the elderly.There is a close relationship between aging,intestinal flora,and glucose and lipid metabolism.Previous studies have focused on GLMD,but no related studies have been reported on glucose and lipid metabolism in the elderly.The liver-gut axis is a key link in regulating glucose and lipid metabolism,cholesterol generates bile acids in the liver,bile acids are converted and reabsorbed by the liver and intestines,and the conversion of bile acids in the intestine depends on the intestinal flora.Therefore,studying this process clearly may be able to find new treatment ideas.Objective:Based on liver-gut axis,first,we study the changes of glucose and lipid metabolism,bile acid metabolism,and intestinal flora of mice with age.On the other hand,the research aims to study the effects of high-sugar and highfat diet on mice under aging,and study the effect and mechanism of Tiahuang formula(THF)on treating it.Method:1.Establish a natural aging model by breeding C57/BL 6J male mice,and start to give two groups of mice a high-sugar and high-fat diet at the age of 12 months to establish an 18-month high-sugar and high-fat model group.The experimental mice were grouped as follows: 4-month-old blank group,12-month-old blank group,18-month-old blank group,18-monthold high-sugar and high-fat model group,and 18-month-old high-sugar and high-fat with THF treatment group,dosing cycle is 6 weeks;2.Test the weight of mice,liver index,spleen and other tissues,and HE staining in the liver and small intestine tissues;3.Fasting blood glucose,blood lipid,insulin,liver function index and glucose tolerance test in mice were tested in accordance with the kit instructions;4.Detection of senescence indicators: combined with mouse behavioral experiments,liver ?-galactosidase staining results,and protein expression of senescence genes p16 and p21;5.Collect the feces,liver tissue and plasma of each group,and use LC-MS to detect the content of various bile acids;6.16 S rDNA sequencing were used to detect the effects on the OTUs,diversity and and differential flora of intestinal microorganisms in each group related microbiota abundance;7.Western blot was used to detect the protein expression of FXRFGF15 signaling pathway related proteins FXR,SHP,CYP7A1 and FGF15,the expression of intestinal tight junction proteins ZO-1,claudin-5 and Occlaudin,and the expression of bile acid transport receptor proteins BSEP,ASBT and MRP2.Result:1.The blood glucose and lipids are gradually increasing with the growing age,and the liver and intestinal tissues gradually show structural damage;The bile acid spectra in liver,feces and plasma were changed,showing a trend of increasing free bile acid and decreasing bile acid,and the abundance and diversity of intestinal flora were decreased;2.The effects of a high-sugar,high-fat diet on aging mice included further increases in blood sugar and lipids,and increased damage to liver and intestinal structures;The content of free bile acid was further increased;The structure of intestinal flora was maladjusted and the content of beneficial bacteria decreased significantly;3.THF has a good lipid-lowering effect,the liver and intestinal structures were restored.The results of intestinal flora showed that THF could significantly improve the intestinal structure disorder of the model group and reduce the amount of bacteria producing BSH.Meanwhile,the results of bile acid metabolomics showed that THF significantly increased the amount of conjugated bile acid in vivo;4.Western blot results showed that THF inhibited the FXR-FGF15 signaling pathway and activated CYP7A1;At the same time up-regulated the expression of bile acid transporter proteins BSEP,MRP2,ASBT and intestinal tight junction proteins Occludin,Claudin-5 and ZO-1.Conclusion:The blood glucose and blood lipids of mice increased with the growing age,the bile acid level and the structure of intestinal flora changed.High-sugar and high-fat diets would lead to further increase in blood lipids and the content of free bile acid,the structure of intestinal flora further deteriorates.THF could inhibit the FXR-FGF15 signaling pathway by reducing the content of free bile acids in the body,activate the expression of CYP7A1 protein,and promote the metabolism and synthesis of bile acids;up-regulates bile acid transporters to promote bile acid transport;up-regulate intestinal tight junction protein,thus exerting the lipid-lowering effect of THF.