| Type 2 diabetes mellitus(T2DM)is a kind of metabolic disease.Under the influence of various factors such as lifestyle and environment,the prevalence of T2 DM is getting higher and higher,and it is also receiving great attention in the field of scientific research.Despite the great progress made in the field of diabetes in the past few decades,there are still many clinical problems.Misdiagnosis and missed diagnosis often occur.Finding unique and effective biomarkers of T2 DM can diagnose,prevent early diseases and provide effective help for patients.In addition,mulberry leaves,as an approved medicine and food homologous Chinese herbal medicine,play an important role in the treatment of T2 DM.However,due to the complex composition of mulberry leaves,there is a lack of comprehensive exploration of the molecular mechanism of treating type 2 diabetes in scientific research.Therefore,this article focuses on three issues: we first induced a mouse model of type 2 diabetes by streptozotocin and performed proteomics studies on the liver to screen for biomarkers associated with T2 DM,laying the foundation for future research and test;in addition,by comparing the physiological parameters and liver proteome changes of normal mice and diabetic mice with mulberry leaf powder aqueous solution,explore the molecular mechanism of mulberry leaf powder aqueous solution for the treatment of T2DM;By constructing a hyperglycemic HepG2 cell model,we performed an intracellular hypoglycemic assay on the main flavonoid component tricetin of mulberry leaf powder,and then identified the intracellular protein targets of tricetin by surface plasmon resonance technique.The bioinformatics and reverse molecular docking tools were also used to analyze the hypoglycemic target and molecular mechanism of tricetin,which laid a scientific foundation for its new hypoglycemic drug candidate.The results of this thesis are:1.Animal models explore biomarkers of T2DM(1)A mouse model of T2 DM was successfully induced by long-term injection of low-dose streptozotocin.(2)Proteomics comparison between normal and type 2 diabetic mice was performed by two-dimensional electrophoresis,and identified by MALDI-TOF-MS.Four proteins were verified at the transcriptional level and protein level: OAT,FBP1,FABP5 and EEF2.2.Evaluation of the efficacy of mulberry leaf powder in the treatment of diabetic mice(1)The type 2 diabetic mice were treated with aqueous solution of mulberry leaf powder,and it was found that mulberry leaves have the effect of lowering blood glucose level and improving serum insulin level in type 2 diabetic mice.(2)By comparing the liver proteomics of mice in the normal group,the diabetic group and the mulberry leaf powder aqueous solution,we identified two differential proteins: MUP2 and FHC.The aqueous solution of mulberry leaf powder significantly reduced the expression of liver MUP2 and increased the expression of FHC.3.Evaluation of hypoglycemic effect of mulberry leaf flavonoids tricetin on hyperglycemic HepG2 cells(1)By incubating high concentrations of glucose,we successfully constructed a hyperglycemic HepG2 cell model.(2)Tricetin has lower toxicity than the common diabetes drug metformin.Moreover,the 2-NBDG trace of the fluorescent glucose analog showed that tricetin had a better effect on promoting glucose uptake at 10?M,indicating that tricetin may be a potential hypoglycemic candidate.(3)Surface plasmon resonance technique and in situ mass spectrometry identified a total of 53 species of HepG2 intracellular protein targets of tricetin.Further bioinformatics analysis of 30 high-affinity binding proteins showed that these proteins mainly involved vitamin D receptor signaling pathway and pathway in cancer.Reverse molecular docking results showed that the four proteins CYP1B1,VDR,PIM1,and GAA had the highest affinity with tricetin. |
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