The Research on Muscle-specific microRNA Mediated Sarcopenia and Exercise Intervention

Objective To observe the effect ofendurance training or resistance trainingon the expression of IGF-1,PGC-1α,MAFbx,Myostatin mRNA and muscle specific microRNA in quadriceps femoris of mice. Methods 36 male mice were randomly distributed into four groups: youth group,old age group,old aerobic group,old resistance group,9 mice in every group. After 17 months training,quadriceps femorismuscles were excised,Muscle-wet weight and body mass( BM) are weighed,muscle specific MicroRNA and sarcopenia-associated genes expressionanalyzed by real-time PCR and Western blot. Results Compared with young group,SI significantly decreased in old group,miR-1 and miR-133a expression and IGF-1 mRNA in the quadriceps femoris muscles were downregulated,but MAFbx mRNA have higher expression,it suggested that the progressive loss of muscle mass occurs with age were related to protein synthesis or catabolism which regulated by IGF-1、MAFbx,and miR-1 or miR-133a may play an important role. lifelong training make miR-1 and miR-133a upregu