Molecular adaptation of skeletal muscle to high‐intensity resistance exercise in aged males

Abstract

Impaired contractile‐induced muscle growth may contribute to sarcopenia: the age‐associated loss of muscle mass and function that is manifested by loss of strength, contractile capacity and endurance. MicroRNAs (miRNAs) are novel posttranscriptional regulators that may play an important role in contractile‐induced adaptations in human skeletal muscle. We performed a study comparing global changes in gene expression using DNA microarrays and PCR arrays targeting 60 specific microRNAs (miRNA) that regulate skeletal muscle metabolism (myo‐miRs), in young (YNG, 22±0.06 yrs) and older (OLD, 74±1.5 yrs) males 6 hours (6H) after a single bout of high‐intensity resistance exercise (RE). We observed in OLD only 48 genes were altered 6H after RE while in YNG there were 201 genes altered by RE. There was no change in the expression of myo‐miRs in OLD after RE and in contrast the expression of myo‐miRs were generally decreased in YNG. These results reveal a significant decrease in the contractile capacity of aging skeletal muscle and may highlight a significant role of myo‐miRs in this decreased response.