Age-related responses to a bout of mechanotherapy in skeletal muscle of rats.

TitleAge-related responses to a bout of mechanotherapy in skeletal muscle of rats.
Publication TypeJournal Article
Year of Publication2019
AuthorsVan Pelt DW, Confides AL, Abshire SM, Hunt ER, Dupont-Versteegden EE, Butterfield TA
JournalJ Appl Physiol (1985)
Volume127
Issue6
Pagination1782-1791
Date Published2019 12 01
ISSN1522-1601
Abstract

Cyclic compressive loading (CCL) is a massage mimetic that improves muscle regrowth from atrophy in adult rats. Therefore, we tested if a single bout of CCL increases anabolic signaling and protein synthesis in muscle during normal, weight-bearing conditions in gastrocnemius muscle from adult and aged rats. Male Brown Norway/F344 rats at 10 (adult) and 30 (aged) months of age were assigned control or CCL (receiving a single bout of CCL). Twenty-four hours following a single bout of CCL there was no change in protein synthesis, Akt, or GSK3β signaling at either age, despite adult rats having higher abundance and activation of mechanosensitive pathways (integrins and integrin-linked kinase). Murf1 was elevated in response to CCL in both age groups, potentially indicating muscle remodeling. Muscle from aged rats exhibited an increase in heat shock protein (HSP) 25 and HSP70 and in the cold shock protein RNA-binding motif 3 (RBM3), demonstrating a unique stress response to CCL in aged muscle only. Finally, muscle from aged rats exhibited higher basal protein synthesis that was corroborated by elevated eIF2Bε and rpS6 signaling, without an additional effect of CCL. In summary, a single bout of CCL does not have anabolic effects on skeletal muscle during normal, weight-bearing conditions, even though it has previously been shown to improve regrowth from atrophy. These data demonstrate that interventions that may help recover from atrophy do not necessarily induce muscle hypertrophy in unperturbed conditions. Massage has been demonstrated to be an effective mechanotherapy to improve recovery from atrophy in adult skeletal muscle; however, this study shows that a single bout of massage fails to increase protein synthesis or anabolic signaling in adult or aged skeletal muscle during normal, weight-bearing conditions. Altogether, our data suggest massage is a useful mechanotherapy for preserving skeletal muscle when combined with other interventions but is not an anabolic stimulus on its own.

DOI10.1152/japplphysiol.00641.2019
Alternate JournalJ. Appl. Physiol.
PubMed ID31670600
PubMed Central IDPMC6962605
Grant ListR01 AT009268 / AT / NCCIH NIH HHS / United States
R21 AG042699 / AG / NIA NIH HHS / United States