Studies On The Role And Mechanism Of Catechins In Mouse Skeletal Muscle Stem Cell Differentiation

Myogenic differentiation is inhibited in patients with sarcopenia and cachexia caused by aging and chronic diseases,and skeletal muscle mass and strength are lost,which seriously affects the quality of life of patients.Catechins,the main active ingredients in tea,have been reported to enhance the performance of skeletal muscle by promoting the differentiation of skeletal muscle stem cells.However,no systematic comparison of the myogenic activities of four major catechin monomers epicatechin(EC),epicatechin gallate(ECG),epigallocatechin(EGC)and epigallocatechin gallate(EGCG)has been made,and the molecular mechanism of their activity also needs to be further explored.Our research mainly focused on the screening of myogenic differentiation-promoting activities of EC,ECG,EGC and EGCG,and further explored and elucidated the dose-effect relationship and mechanism of their differentiation-promoting activities.The main results are as follows:Firstly,different concentrations of catechin monomer were used to intervene in the differentiation of mouse skeletal muscle myoblasts(C2C12 cells),the number,length and diameter of differentiated mature myotubes were counted,and the mRNA expressions of myotube differentiation markers MyOG,MyOD and MyHC were detected.The differentiation activity of EC,ECG,EGC and EGCG was assessed from two aspects of cell phenotype and gene expression level.The results showed that ECG enhanced the differentiation ability of skeletal muscle stem cells more strongly than other catechin monomers,and the optimum concentration of ECG for myogenic differentiation was 10 ?M.Secondly,atomic force microscopy was used to explore the effects of ECG on the mechanical properties of myotube cell adhesion,stiffness and Young's modulus.It was found that ECG significantly increased the height of myotube cells(about 178.5%)and decreased the adhesion force,stiffness and Young's modulus of myotube cells.Finally,the LC/MS proteomic strategy combined with IPA analysis was used to explore the molecular mechanism of ECG enhancing differentiation of C2C12 cells.It was found that ECG could promote differentiation through mTOR and Wnt/?-catenin signaling pathways.