title: Endurance training increases the efficiency of rat skeletal muscle mitochondria.
abstract: Endurance training enhances mitochondrial oxidative capacity, but its effect on mitochondria functioning is poorly understood. In the present study, the influence of an 8-week endurance training on the bioenergetic functioning of rat skeletal muscle mitochondria under different assay temperatures (25, 35, and 42 °C) was investigated. The study was performed on 24 adult 4-month-old male Wistar rats, which were randomly assigned to either a treadmill training group (n = 12) or a sedentary control group (n = 12). In skeletal muscles, endurance training stimulated mitochondrial biogenesis and oxidative capacity. In isolated mitochondria, endurance training increased the phosphorylation rate and elevated levels of coenzyme Q. Moreover, a decrease in mitochondrial uncoupling, including uncoupling protein-mediated proton leak, was observed after training, which could explain the increased reactive oxygen species production (in nonphosphorylating mitochondria) and enhanced oxidative phosphorylation efficiency. At all studied temperatures, endurance training significantly augmented H2O2 production (and coenzyme Q reduction level) in nonphosphorylating mitochondria and decreased H2O2 production (and coenzyme Q reduction level) in phosphorylating mitochondria. Endurance training magnified the hyperthermia-induced increase in oxidative capacity and attenuated the hyperthermia-induced decline in oxidative phosphorylation efficiency and reactive oxygen species formation of nonphosphorylating mitochondria via proton leak enhancement. Thus, endurance training induces both quantitative and qualitative changes in muscle mitochondria that are important for cell signaling as well as for maintaining muscle energy homeostasis, especially at high temperatures.
authors: Department of Muscle Physiology, Chair of Physiology and Biochemistry, Faculty of Rehabilitation, University School of Physical Education, 31-571, Krakow, Poland. jerzy.zoladz@awf.krakow.pl.
authors: Jerzy A
authors: JA
authors: Zoladz
authors: Department of Bioenergetics, Adam Mickiewicz University, 61-614, Poznan, Poland.
authors: Agnieszka
authors: A
authors: Koziel
authors: Department of Bioenergetics, Adam Mickiewicz University, 61-614, Poznan, Poland.
authors: Andrzej
authors: A
authors: Woyda-Ploszczyca
authors: Department of Neurobiology, University School of Physical Education, 61-871, Poznan, Poland.
authors: Jan
authors: J
authors: Celichowski
authors: Department of Bioenergetics, Adam Mickiewicz University, 61-614, Poznan, Poland.
authors: Wieslawa
authors: W
authors: Jarmuszkiewicz
mesh_terms: D000818:Animals; D006861:Hydrogen Peroxide / Q000378:metabolism; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D010085:Oxidative Phosphorylation; D010805:Physical Conditioning, Animal; D010807:Physical Endurance; D005082:Physical Exertion; D051381:Rats; D017208:Rats, Wistar; D014451:Ubiquinone / Q000378:metabolism
chemical_list: D014451:Ubiquinone; D006861:Hydrogen Peroxide
keywords: Endurance training; Mitochondria functioning; Oxidative phosphorylation; Reactive oxygen species; Skeletal muscle mitochondria; Temperature; Uncoupling protein