Tea Polyphenols And Pomegranate Peel Polyphenols Improve 3T3-L1 Adipocyte Insulin Resistance And Its Molecular Mechanism

Insulin resistance(IR)refers to the phenomenon that the insulin-sensitivity of target organs or tissues,such as liver,adipose tissue,and muscle tissue,to normal physiological concentrations is reduced so that normal biological effects cannot be achieved.The main manifestations are the weakening of the liver's ability to degrade glucose and the reduction of fat and muscle tissue's ability to consume glucose.In this experimental,3T3-L1 adipocytes that were induced to differentiate were studied and insulin resistance model were induced by dexamethasone.Using TP and its main components EGCG,CAF,ECG.PPPs and its main components PC,EA,and GA,to observe the effect of plant polyphenols on glucose consumption in insulin resistant adipocytes.The plant polyphenol ECG with the best effect of promoting glucose consumption was screened out.Real-time PCR and Western-blot immunoblotting were used to detect intracellular insulin signaling and related cytokine genes IRS-1,PI3K,AKT,GLUT4,PPARy,adiponectin,leptin,resistin,TNF-a mRNA expression and IRS-1,p-IRS-1,AKT,p-AKT and GLUT4 protein expression,to explore the molecular mechanism of plant polyphenols improving insulin resistance in adipocytes.The results of the study are as follows:(1)3T3-L1 preadipocytes can be induced to differentiate into lipid-rich mature adipocytes by 3-isobutyl-l-methylxanthine,dexamethasone,and insulin.Dexamethasone was used to establish a model of insulin resistance on adipocytes.(2)TP and its main components EGCG,ECG,PPPs and its main components PC,EA,and GA can promote the glucose resistance of dexamethasone-induced in insulin resistant adipocytes,among them,ECG has the best effect of promoting glucose consumption at low doses and it can inhibit the differentiation of 3T3-L1 preadipocytes.(3)Through ECG intervention,it can upregulate the expression of PI3K,AKT,GLUT4,adiponectin,and down-regulate TNF-a mRNA expression in adipocytes,but no significant effect on the expression of IRS-1,PPARty,leptin,resistin.It also can up-regulate the expression of p-IRS-1,p-AKT and GLUT4,and have no significant effect on the expression of RS-1 and AKT protein.(4)The molecular mechanism of plant polyphenol ECG improve insulin resistance in adipocytes by activating the insulin signaling pathway IRS-1/PI3K/AKT in adipose tissue to achieve the phosphorylation reaction,thereby promoting the adipose tissue to ingest and use glucose.