Mechanisms of Atrophy and Myosin Heavy Chain Co-expression in Aging Muscle.

摘要

Sarcopenia is the age related loss of skeletal muscle mass and skeletal muscle function. It causes impairment of mobility activities and can lead to reduced quality of life of elderly persons. Currently, the cause of sarcopenia is unknown and there are no effective methods for its treatment. Recent findings from our lab implicate denervation as the primary instigator of myofiber atrophy leading to the loss of skeletal muscle mass observed in sarcopenia. Using immunolabelling for MuRF1, MHCs and MHCf protein expression, we examined the involvement of the proteasomal protein degradation system in sarcopenia in the context of denervation, as well as the morphology of sarcopenic muscles of different myofiber type compositions. We found that MuRF1 expression was elevated in a denervation specific manner in sarcopenia, that sarcopenic muscle is characterised by marked MHC co-expression and muscle specific shifts in MHC expression, and that MHCs myofibers are not protected from atrophy.