Expression Analysis of Irisin During Different Differentiation Stages of Skeletal Muscle Cells

Background: As a newly discovered muscle factor secreted by skeletal muscle cells, irisin is a polypeptide fragment formed after hydrolysis by fibronectin type Ⅲ domain-containing protein 5 (FNDC5). Previous studies have shown that irisin has biological functions that promote beigeing of WAT, regulate glucose and lipid metabolism. However, the functions of irisin in muscle development and muscle fat metabolism remain unknown. Results: : In order to study the expression of irisin in different growth stages of skeletal muscle, this study used SPF mice as experimental subjects to select skeletal muscle cells and muscle tissues of different developmental stages of mice. The expression of irisin precursor FNDC5 in different stages of cells and tissues was detected by western blotting and real-time fluorescent quantitative PCR, and the expression of FNDC5 in cells was detected by immunofluorescence. The results showed that FNDC5 was expressed in all stages of tissues and cells, but the expression was different at different stages. FNDC5 protein has the highest expression in muscle of sexually mature mice, followed by elderly mice and adolescent mice, and low expression in pups. Secondly, FNDC5 protein is mainly expressed in the cytoplasm and highest in muscle fibers. The myotubes were the second, and the lowest in C2C12 cells. Conclusions: : This experiment can provide a theoretical basis for the subsequent study of irisin in skeletal muscle, and lay the foundation for targeted therapy of related diseases.