Trewin 2018 Am J Physiol Regul Integr Comp Physiol
|Trewin AJ, Parker L, Shaw CS, Hiam D, Garnham AP, Levinger I, McConell GK, Stepto NK (2018) Acute HIIE elicits similar changes in human skeletal muscle mitochondrial H2O2 release, respiration and cell signaling as endurance exercise even with less work. Am J Physiol Regul Integr Comp Physiol [Epub ahead of print].|
Abstract: It remains unclear whether high-intensity interval exercise (HIIE) elicits distinct molecular responses to traditional endurance exercise relative to the total work performed. We aimed to investigate the influence of exercise intensity on acute perturbations to skeletal muscle mitochondrial function (respiration and reactive oxygen species), metabolic and redox signaling responses. In a randomized, repeated measures crossover design, eight recreationally active individuals (24 ± 5 years; VO2peak 48 ± 11 mL.kg-1.min-1) undertook continuous moderate-intensity (CMIE: 30 min, 50% peak power output [PPO]), high-intensity interval (HIIE: 5x4 min, 75% PPO, work-matched to CMIE), and low-volume sprint interval (SIE: 4x30 s) exercise, ≥7 days apart. Each session included muscle biopsies at baseline, immediately and 3 h post-exercise for high-resolution mitochondrial respirometry (JO2) and H2O2 emission (JH2O2), gene and protein expression analysis. Immediately post-exercise and irrespective of protocol, JO2 increased during complex I+II leak/state-4 respiration but JH2O2 decreased (p<0.05). AMP-activated protein kinase (AMPK) and acetyl co-A carboxylase (ACC) phosphorylation increased ~1.5 and 2.5-fold respectively, while thioredoxin-reductase-1 protein abundance was ~35% lower after CMIE vs. SIE (p<0.05). At 3 hours post-exercise, regardless of protocol, JO2 was lower during both ADP-stimulated state-3 OXPHOS and uncoupled respiration (p<0.05) but JH2O2 trended higher (p<0.08); PPARGC1A mRNA increased ~13-fold, and peroxiredoxin-1 protein decreased ~35%. In conclusion, intermittent exercise performed at high intensities has similar dynamic effects on muscle mitochondrial function compared with endurance exercise, irrespective of whether total workload is matched. This suggests exercise prescription can accommodate individual preferences while generating comparable molecular signals known to promote beneficial metabolic adaptations.
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Organism: Human Tissue;cell: Skeletal muscle Preparation: Permeabilized tissue Enzyme: Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase
Coupling state: LEAK, OXPHOS, ET Pathway: N, S, NS, ROX HRR: Oxygraph-2k, O2k-Fluorometer
Labels, 2018-10, Amplex UltraRed