Balanced Free Essential Amino Acids and Resistance Exercise Training Synergistically Improve Dexamethasone-Induced Impairments in Muscle Strength, Endurance, and Insulin Sensitivity in Mice.
Jiwoong JangJin-Ho KohYeongmin KimHee-Joo KimSanghee ParkYewon ChangJiyeon JungRobert R WolfeIl-Young KimPublished in: International journal of molecular sciences (2022)
Our previous study shows that an essential amino acid (EAA)-enriched diet attenuates dexamethasone (DEX)-induced declines in muscle mass and strength, as well as insulin sensitivity, but does not affect endurance. In the present study, we hypothesized that the beneficial effects will be synergized by adding resistance exercise training (RET) to EAA, and diet-free EAA would improve endurance. To test hypotheses, mice were randomized into the following four groups: control, EAA, RET, and EAA+RET. All mice except the control were subjected to DEX treatment. We evaluated the cumulative rate of myofibrillar protein synthesis (MPS) using 2 H 2 O labeling and mass spectrometry. Neuromuscular junction (NMJ) stability, mitochondrial contents, and molecular signaling were demonstrated in skeletal muscle. Insulin sensitivity and glucose metabolism using 13 C 6 -glucose tracing during oral glucose tolerance tests were analyzed. We found that EAA and RET synergistically improve muscle mass and/or strength, and endurance capacity, as well as insulin sensitivity, and glucose metabolism in DEX-treated muscle. These improvements are accomplished, in part, through improvements in myofibrillar protein synthesis, NMJ, fiber type preservation, and/or mitochondrial biogenesis. In conclusion, free EAA supplementation, particularly when combined with RET, can serve as an effective means that counteracts the adverse effects on muscle of DEX that are found frequently in clinical settings.
Keyphrases
- skeletal muscle
- insulin resistance
- amino acid
- high fat diet induced
- mass spectrometry
- oxidative stress
- high intensity
- low dose
- diabetic rats
- physical activity
- resistance training
- randomized controlled trial
- high resolution
- metabolic syndrome
- double blind
- open label
- blood glucose
- smoking cessation
- blood pressure
- endothelial cells
- simultaneous determination
- adverse drug