Sugar Absorption Function Of Small Intestine Under The Expression Of Adipose Tissue-Specific NSREBP1c And FTZ Intervention

Objective:1.To observe the pathological morphology of small intestine and the characteristics of intestinal glucose absorption function in aP2-nSREBP1c transgenic mice with non-obese glycolipid disorder.2.To investigate the pathological morphology of mesenteric fat in the state of fat atrophy caused by fat metabolism disorder in aP2-nSREBP1c mice,the correlation between mesenteric fat and intestinal function,and the possible relationship between SREBPs and intestinal sugar absorption function.3.From the point of view of intestinal glucose absorption,to observe the effect of FTZ on intestinal morphology and function under the improvement of glucose metabolism in aP2-nSREBP1c fat atrophy model mice,and to explore the mechanism of FTZ in improving glycolipid metabolic disease.Methords:1.Sugar Absorption Function of Small Intestine under the Expression of Adipose Tissue-Specific nSREBP1c.The details are as follows:1.1 The aP2-nSREBP1c mice were randomly divided into two groups after genotyping,and the changes of food intake and body weight were recorded every week.Fasting blood and random blood were taken every 3 weeks to dynamically observe the levels of GLU,TG,TC,HDL-C and LDL-C.1.2 The oral glucose tolerance test（OGTT）and intraperitoneal injection of glucose tolerance test（IPGTT）were carried out at the age of 14 weeks.1.3 And the urine D-xylose test was carried out at the age of 16 weeks.1.4 The 18-week-old mice were labeled with BrdU in vivo,and the cervical vertebrae were dislocated and killed one hour later.The length and weight of intestine were measured,the proliferation of jejunum was observed by immunohistochemical staining with specific binding of anti-BrdU antibody,1.5 and the pathological status of duodenum,jejunum,ileum and mesenteric adipose tissue was observed by hematoxylin-eosin（HE）staining.1.6 Real-time fluorescence quantitative analysis（RT-PCR）was used to detect mesenteric fat apelin,resistin,adiponectin and other fat factors,duodenum and jejunum related mRNA levels,including sugar absorption related Slc5a1,Slc2a1,Slc2a2,Slc2a5,Sgk1;gluconeogenesis related G6pc,CREB,PEPCK;gastrointestinal hormone related GIP,GCG,CHGA;anti-apoptosis related IL15,BCL2L1,MCL1,BCL3;proliferation related Ki67,TGFβ,Gsk3β,β-catenin;inflammatory factors related TNFα,IL10,IL4,IL6;nuclear transcription factors SREBP1,SREBP2,PPARα,PPARβand PPARγ;1.7 The levels of sugar transport related proteins such as SGLT1,SGLT2,GLUT2 and GLUT5 in jejunum were detected by Western-blot;1.8 the protein expression of GLUT2and SGLT2 in jejunum were observed by immunofluorescence.1.9 The sugar absorption function of small intestine was detected by unidirectional glucose perfusion test in vivo of 25-week-old mice.2.The Effect and Mechanism of FTZ to improve sugar metabolism in aP2-nSREBP1c mice.2.1 8-week-old aP2-nSREBP1c mice were randomly divided into 7 groups,model group（T）,metformin group（Met）,Fufang Zhenzhu Tiaozhi Formula（FTZ）high（FH）,middle（FM）,low（FL）dose group,and wild type in the same nest as control group（W）.There were 6 mices in each group.2.2 Metformin group(250 mg·kg^-1)and FTZ high,middle and low dose groups(2.4 g·kg^-1,1.2 g·kg^-1,0.6 g·kg^-1)were administered intragastrically for 16 weeks.The mice in the control group and the model group were given the same volume of distilled water intragastrically,and the changes of body mass were recorded.2.3 At the end of12 weeks,GLU,TC and TG in blood were measured by fundus venous plexus blood,2.4 and the length of intestinal canal was measured at the end of 16 weeks.2.5 The morphological changes of duodenum,jejunum,ileum and mesenteric fat were observed by hematoxylin-eosin staining（HE）.2.6 Real-time fluorescence quantitative PCR（RT-qPCR）was used to detect the levels of sugar transport related mRNA Slc5a1,Slc2a1,Slc2a2,Slc2a5,Sgk1 in jejunum and the levels of anti-apoptosis related mRNA IL15,BCL2L1,MCL-1 and BCL3,2.7 and the protein expression of GLUT2 and SGLT2 in jejunum was detected by immunofluorescence.Results:1.The aP2-nSREBP1c lipodystrophy mice had the phenotype of non-obese glycolipid metabolism disorder,the increase of the length of small intestine and intestinal villi,the high expression of Ki67 and TGFβmRNA related to jejunal proliferation,and the up-regulation of IL15,BCL2L1 and other mRNA levels related to anti-apoptosis.The increase of urinary D-xylose excretion rate,the increase of total glucose absorption in small intestine,the down-regulation of sugar transport related mRNA and protein levels such as SGLT1 and GLUT2in duodenum and jejunum,and the up-regulation of G6pc level,the key gene of gluconeogenesis in jejunum.2.In the aP2-nSREBP1c lipodystrophy mice,the number of mesenteric adipocytes decreased sharply,the abundance of connective tissue increased,the invasion of inflammation increased,the expression of mesenteric adipose factor adiponectin was low,and the expression of jejunal tight junction protein ZO-1and claudin4 was high.The ability of small intestinal mechanical barrier was strengthened,the nuclear transcription mRNA of SREBP1,SREBP2,PPARαand PPARβin duodenum was down-regulated,the expression of PPARγin jejunum was high,while the levels of SREBP2,PPARαand PPARγmRNA in mesenteric fat were decreased.3.After 16 weeks of administration of FTZ,the blood glucose and plasma total cholesterol of aP2-nSREBP1c lipodystrophy mice were decreased,the length of intestine and villi was shortened,the expression level of GLUT2mRNA and protein in jejunum was up-regulated,the morphology of mesenteric fat was restored,and the invasion of inflammation was reduced.Conclusion:1.The aP2-nSREBP1c lipodystrophy mice have the phenotype of glycolipid metabolism disorder,fat atrophy,small intestinal hyperplasia and abnormal glucose absorption function of small intestine.Mesenteric fat atrophy in aP2-nSREBP1c mice resulted in the loss of immune barrier function and induced adaptive changes of intestinal mechanical barrier function.SREBPs signal may be involved in the regulation of duodenal glucose sensing and transport,and PPARγis closely related to small intestinal hyperplasia.2.There is a diet-independent feedback regulation mechanism between intestinal SGLTs-GLUTs and the body to maintain the homeostasis of glucose metabolism.In the state of fatty liver or fat atrophy,the peripheral organs make insufficient use of glucose,the body maintains a hyperglycemic state,and the intestinal SGLTs-GLUTs level is down-regulated;the increased use of glucose by the body can feedback up-regulate the intestinal uptake of exogenous glucose,The level of intestinal SGLTs-GLUTs was up-regulated.3.FTZ can improve the pathological morphology and function of fat and liver in aP2-nSREBP1c mice,so as to increase the glucose uptake and utilization by peripheral organs.Improve intestinal morphology and sugar absorption function through dialogue and adaptability between the body and the intestinal tract,Play a comprehensive role in improving glucose and lipid metabolism disease.