Petrick 2019 J Physiol
|Petrick HL, Pignanelli C, Barbeau PA, Churchward-Venne TA, Dennis KMJH, van Loon LJC, Burr JF, Goossens GH, Holloway GP (2019) Blood flow restricted resistance exercise and reductions in oxygen tension attenuate mitochondrial H2O2 emission rates in human skeletal muscle. J Physiol [Epub ahead of print].|
Abstract: Low-load blood flow restricted resistance exercise (BFR-RE) training has been proposed to induce comparable adaptations to traditional resistance exercise (RE) training, however the acute signaling events remain unknown. While a suggested mechanism of BFR-RE is an increase in reactive oxygen species (ROS) production, oxygen partial pressure (pO2) is reduced during BFR-RE, and the influence of O2 tension on mitochondrial redox balance remains ambiguous. We therefore aimed to determine if skeletal muscle mitochondrial bioenergetics were altered following an acute bout of BFR-RE or RE, and to further examine the role of pO2 in this response. To study this, muscle biopsies were obtained from 10 males at rest and 2 h after performing 3 sets of single-leg squats (RE or BFR-RE) to failure at 30% 1-RM. We determined that mitochondrial respiratory capacity and ADP sensitivity were not altered in response to RE or BFR-RE. While maximal (succinate) and submaximal (non-saturating ADP) mitochondrial ROS emission rates were unchanged following RE, BFR-RE attenuated these responses ∼30% compared to pre-exercise, occurring along with a reduction in skeletal muscle tissue oxygenation during BFR-RE (p < 0.01 vs. RE). In a separate cohort of participants, evaluation of mitochondrial bioenergetics in vitro revealed that mild O2 restriction (50 μm) dramatically attenuated maximal (∼4-fold) and submaximal (∼50-fold) mitochondrial ROS emission rates and the fraction of electron leak to ROS compared to room air (200 μm). Combined, these data demonstrate that mitochondrial ROS emissions are attenuated following BFR-RE, a response which may be mediated by a reduction in skeletal muscle pO2.
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Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Stress:Oxidative stress;RONS 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 Regulation: ADP, Oxygen kinetics Coupling state: LEAK, OXPHOS Pathway: N, NS HRR: Oxygraph-2k