Time course of proteolytic, apoptotic, and cytokine gene expression after resistance exercise in humans
2007; Wiley; Volume: 21; Issue: 6 Linguagem: Inglês
10.1096/fasebj.21.6.a937-d
ISSN1530-6860
AutoresEmily Louis, Ulrika Raue, Bożena Jemioło, Yifan Yang, Scott Trappe,
Tópico(s)Sports injuries and prevention
ResumoThe aim of this study was to examine the time course activation of select proteolytic [muscle RING finger-1 (MuRF-1), atrogin-1, Forkhead box 3A (FOXO3A), calpain-1, and calpain-2], apoptotic [B-cell leukemia/lymphoma (Bcl-2), Bcl-2 associated X protein (BAX), cysteine-dependent aspartate protease (caspase) -3], myostatin, and cytokine [interleukin (IL) -6, -8, and -15, and tumor necrosis factor (TNF) -α] genes after an acute bout of resistance exercise (RE). Six subjects (25 ± 4 yr, 72 ± 14 kg) had eight muscle biopsies taken from the vastus lateralus before, immediately after, 1, 2, 4, 8, 12, and 24 h after 3 X 10 knee extensions at 70% of max. Using real-time RT PCR, mRNA was amplified and normalized to GAPDH. RE increased (p<0.05) proteolytic mRNA of MuRF-1 (2.0 to 3.5-fold, 1–4 h), and decreased FOXO3A (1.7-fold, 8–12 h). Apoptotic mRNA levels were increased for the BAX/Bcl-2 ratio (1.9-fold, 24 h). Myostatin gene expression decreased (2.5 to 6.3-fold, 1–24 h). RE also increased cytokine mRNA levels of IL-6 (4 to 791-fold, 4–24 h), IL-8 (9 to 759-fold, 2–12 h), and TNFα (2.1 to 6.3, 0–24 h). With RE, there was no change for atrogin-1, calpain-1, calpain-2, BAX, Bcl-2, caspase-3, and IL-15. In general, the selected genes showed variability in the timing of expression. Cytokine mRNA levels appeared to peak 4–8 hours post RE, while MuRF-1 peaked 1–2 h post RE. Myostatin and TNFα showed a difference from basal levels throughout the 24 h post RE. These data suggest a potential contribution to muscle remodeling after RE via an increase of cytokine and MuRF-1 mRNA in concert with decreased myostatin mRNA. Supported by NIH grant AG18409
Referência(s)