INTRODUCTION: The nuclear factor kappa B (NF-κβ) signaling cascade is responsible for mediating stress-activated catabolic effects of Tumor Necrosis Factor Alpha (TNF-α) downstream of the TNF receptor (TNFR1). NF-κβ transcription factor remains inhibited in the cytosol of the muscle and can be stimulated for translocation and transcription by a variety of external stimuli, most notably by pro-inflammatory cytokines and oxidative stress. Nevertheless, currently there is a gap in the literature with regard to the time course effect of NF-κβ signaling following acute resistance exercise in humans. PURPOSE: To observe the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF- κβ signaling. METHODS: Twenty-eight untrained males were assigned to either a control (CON; n=11) or exercise group (EX; n=17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1HR), 5-hour (5HR), and 48-hours (48HR) post-resistance exercise. Multiplex signaling assay kits (EMD Millipore, Billerica, MA, USA) were used to quantify the total protein (TNFR1, c-Myc) or phosphorylation status of proteins (IKKa/b, NF- κβ, IkB) specific to apoptotic signaling pathways using MAGPIX® (Luminex, Austin, TX, USA). Repeated measures ANOVA analysis was used to determine the effects of the exercise bout on intramuscular signaling at each timepoint. Additionally, change scores were analyzed by magnitude based inferences to determine a mechanistic interpretation. RESULTS: Repeated measures ANOVA indicated a trend for a two way interaction between the EX and CON Group (p=0.064). Magnitude based inferences revealed a "Very Likely" increase in total c-Myc from PRE-5H and a "Likely" increase in IkB phosphorylation from PRE-5H. CONCLUSION: Results indicate that c-Myc transcription factor and phosphorylation of IkB are elevated following acute intense resistance exercise in untrained males. These data suggest that NF- κβ signaling plays a role in ribosome biogenesis and skeletal muscle regeneration following resistance exercise in young untrained males.
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Doctor of Philosophy (Ph.D.)
College of Education and Human Performance
Education; Exercise Physiology
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Townsend, Jeremy, "Intramuscular TNF-alpha signaling in response to resistance exercise and recovery in untrained males." (2016). Electronic Theses and Dissertations, 2004-2019. 4962.