Study On The Effect Of Epicatechin On Insulin Resistance In C2C12 Cells

Epicatechin（EC）is a water-soluble natural organic compound that is widely found in tea,cocoa,fruits and other crops.EC belongs to the flavanol group of compounds and has a variety of physiological activities,such as anti-inflammatory,antioxidant,mitochondrial disease treatment,and cardiovascular disease prevention.Type 2 diabetes is a major disease endangering human health worldwide,and the research on its related pathogenesis is still incomplete.In recent years,studies have found that insulin resistance（IR）is a key factor in the occurrence of type 2 diabetes.The three key target tissues for insulin action in the body are skeletal muscle,liver,and adipose tissue.In skeletal muscle,insulin promotes glucose utilization and storage by increasing glucose transport and glycogen synthesis.Therefore,the study of how to improve C2C12 myogenic cell IR has some basic research value for the treatment of type 2 diabetes mellitus.In addition,type 2 diabetes is also more closely related to oxidative stress injury.Therefore,in this paper,we established an insulin-resistant cell model by palmitic acid（PA）-induced C2C12 myogenic cells,evaluated their hypoglycemic effect in vitro,clarified the biological activity of EC in regulating glucose metabolism,and provided new ideas for the treatment of type 2diabetes from the perspective of basic research.The main results are as follows:（1）The effect of different concentrations of EC on the viability of C2C12myogenic cells was determined by the MTT method,and EC at concentrations of 200,400,and 800μmol/L were selected for the experiment.HE staining was performed to observe the cell morphology and identify C2C12 cells successfully differentiated into C2C12 myogenic cells.Insulin-resistant cell models were successfully established using PA.Glucose consumption was measured by glucose oxidase assay and glycogen content was measured by anthrone assay.The results showed that EC significantly increased glucose consumption and glycogen content in C2C12 cells.（2）The effect of EC on the oxidative index of C2C12 cells was examined.The results showed that EC could increase the levels of CAT,SOD,and GSH in C2C12cells and decrease the levels of NO,MDA,and ROS in C2C12 cells,suggesting that EC has a repairing effect on oxidative stress damage in C2C12 cells.（3）The in vitro antioxidant activity of EC was measured.The results showed that the scavenging rate of DPPH⁺radicals,ABTS⁺radicals,and Fe³⁺reduction capacity of EC increased with the increase of mass concentration,indicating that the in vitro antioxidant activity of EC was stronger.（4）The apoptosis of C2C12 cells was significantly reduced by EC using flow cytometry,suggesting that EC can alleviate oxidative stress damage by reducing the apoptosis rate.（5）The effects of EC on the regulation of the insulin signaling pathway and oxidative stress signaling pathway in C2C12 cells were evaluated by Western blot.EC treatment resulted in the upregulation of GLUT4 protein level,activation of PI3K/AKT/m TOR signaling pathway,activation of AMPK/ACC signaling pathway,and activation of NRF2/HO-1 oxidative stress signaling pathway in C2C12 cells.This indicates that EC ameliorates IR in C2C12 myogenic cells by regulating cellular oxidative stress signaling pathways,activating insulin-dependent and insulin-independent signaling pathways,and enhancing GLUT4 translocation to the plasma membrane of IR cells to increase cellular uptake of glucose under IR conditions.In summary,EC has a significant ameliorative effect on IR in C2C12 myogenic cells,and its mechanism is to regulate the NRF2/HO-1 signaling pathway,repair oxidative stress damage and alleviate apoptosis;increase glycogen synthesis,activate the PI3K/AKT/m TOR signaling pathway,upregulate the ability of GLUT4 expression and translocation,and activate the AMPK/ACC pathway to enhance cellular uptake of glucose.The study may contribute to the development of diabetes and related diseases.This study can provide reference data for the treatment of diabetes and related diseases,and also provide new ideas for the future development and utilization of tea resources.