Title | Elevated myonuclear density during skeletal muscle hypertrophy in response to training is reversed during detraining. |
Publication Type | Journal Article |
Year of Publication | 2019 |
Authors | Dungan CM, Murach KA, Frick KK, Jones SR, Crow SE, Englund DA, Vechetti IJ, Figueiredo VC, Levitan BM, Satin J, McCarthy JJ, Peterson CA |
Journal | Am J Physiol Cell Physiol |
Volume | 316 |
Issue | 5 |
Pagination | C649-C654 |
Date Published | 2019 05 01 |
ISSN | 1522-1563 |
Keywords | Animals, Female, Hypertrophy, Mice, Mice, Inbred C57BL, Muscle Fibers, Skeletal, Physical Conditioning, Animal, Weight-Bearing |
Abstract | Myonuclei gained during exercise-induced skeletal muscle hypertrophy may be long-lasting and could facilitate future muscle adaptability after deconditioning, a concept colloquially termed "muscle memory." The evidence for this is limited, mostly due to the lack of a murine exercise-training paradigm that is nonsurgical and reversible. To address this limitation, we developed a novel progressive weighted-wheel-running (PoWeR) model of murine exercise training to test whether myonuclei gained during exercise persist after detraining. We hypothesized that myonuclei acquired during training-induced hypertrophy would remain following loss of muscle mass with detraining. Singly housed female C57BL/6J mice performed 8 wk of PoWeR, while another group performed 8 wk of PoWeR followed by 12 wk of detraining. Age-matched sedentary cage-dwelling mice served as untrained controls. Eight weeks of PoWeR yielded significant plantaris muscle fiber hypertrophy, a shift to a more oxidative phenotype, and greater myonuclear density than untrained mice. After 12 wk of detraining, the plantaris muscle returned to an untrained phenotype with fewer myonuclei. A finding of fewer myonuclei simultaneously with plantaris deconditioning argues against a muscle memory mechanism mediated by elevated myonuclear density in primarily fast-twitch muscle. PoWeR is a novel, practical, and easy-to-deploy approach for eliciting robust hypertrophy in mice, and our findings can inform future research on the mechanisms underlying skeletal muscle adaptive potential and muscle memory. |
DOI | 10.1152/ajpcell.00050.2019 |
Alternate Journal | Am. J. Physiol., Cell Physiol. |
PubMed ID | 30840493 |
PubMed Central ID | PMC6580158 |
Grant List | F32 AR071753 / AR / NIAMS NIH HHS / United States R01 AG046920 / AG / NIA NIH HHS / United States R01 AG049806 / AG / NIA NIH HHS / United States R01 AR060701 / AR / NIAMS NIH HHS / United States |