Aerobic Exercise-Mediated Prevention Against Glucocorticoid Myopathy in Aged Skeletal Muscle

Older adults are vulnerable to glucocorticoid-induced muscle atrophy and weakness, with sex potentially influencing susceptibility to those effects. Aerobic exercise can reduce glucocorticoid-induced muscle atrophy in young rodents. However, it is unknown whether aerobic exercise can antagonize glucocorticoid myopathic features in aged muscle. The objectives of this study were to define the extent to which sex influences the development of glucocorticoid myopathy in aged muscle, and to determine the extent to which moderate intensity aerobic exercise training protects against development of myopathy. 24-month-old female (n=30) and male (n=33) mice were randomized to either sedentary or aerobic exercise groups. Within their respective groups, mice were randomized to either daily treatment with injections of dexamethasone (DEX) or saline. Following treatments, the contractile properties of the triceps surae complex were assessed in situ. DEX marginally lowered muscle mass and soluble protein content in both sexes, which was attenuated by aerobic exercise only in females. DEX-treated females expressed greater sub-tetanic contractile properties in a sex-specific manner, which were not influenced by aerobic exercise. DEX increased muscle fatigue in both sexes, but aerobic exercise prevented the fatigue induction only in females. The sex-specific differences to muscle function in response to DEX treatment coincided with sex-specific changes to the contents of protein related to calcium handling, mitochondrial quality control, and glucocorticoid receptor in muscle. These findings define several important sexually dimorphic changes to aged skeletal muscle physiology in response to glucocorticoid treatment and define the capacity of short-term aerobic exercise to protect against those changes.

Grantor dc:publisher

Florida State University

Year dc:date

2024

Contributors dc:contributor

• Laskin, Grant R. (author)
• Gordon, Bradley S. (professor directing dissertation)
• Chase, P. Bryant (university representative)
• Hwang, Hyun Seok (committee member)
• Solis, Christopher (committee member)
• Florida State University (degree granting institution)
• College of Education, Health, and Human Sciences (degree granting college)
• Department of Health, Nutrition, and Food Sciences (degree granting department)

• Physiology

Language dc:language

English

Identifier

fsu:927960
iid: Laskin_fsu_0071E_18506

OAI identifier oai:identifier

oai:diginole.lib.fsu.edu:fsu_927960