title: Short-duration intermittent hypoxia enhances endurance capacity by improving muscle fatty acid metabolism in mice.
abstract: This study was designed to (1) investigate the effects of acute short-duration intermittent hypoxia on musclemRNAand microRNAexpression levels; and (2) clarify the mechanisms by which short-duration intermittent hypoxia improves endurance capacity. Experiment-1: Male mice were subjected to either acute 1-h hypoxia (12% O2), acute short-duration intermittent hypoxia (12% O2for 15 min, room air for 10 min, 4 times, Int-Hypo), or acute endurance exercise (Ex). The expression of vascular endothelial growth factor-AmRNAwas significantly greater than the control at 0 h post Ex and 6 h post Int-Hypo in the deep red region of the gastrocnemius muscle. miR-16 expression levels were significantly lower at 6 and 10 h post Int-Hypo. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)mRNAlevels were significantly greater than the control at 3 h post Ex and 6 h post Int-Hypo. miR-23a expression levels were lower than the control at 6-24 h post Int-Hypo. Experiment-2: Mice were subjected to normoxic exercise training with or without intermittent hypoxia for 3 weeks. Increases in maximal exercise capacity were significantly greater by training with short-duration intermittent hypoxia (IntTr) than without hypoxia. Both 3-Hydroxyacyl-CoA-dehydrogenase and total carnitine palmitoyl transferase activities were significantly enhanced in IntTr. Peroxisome proliferator-activated receptor delta andPGC-1α mRNAlevels were both significantly greater in IntTr than in the sedentary controls. These results suggest that exercise training under normoxic conditions with exposure to short-duration intermittent hypoxia represents a beneficial strategy for increasing endurance performance by enhancing fatty acid metabolism in skeletal muscle.
authors.affiliation: Laboratory of Exercise Physiology, Health and Sports Sciences, Course of Sports Education, Department of Education, Hokkaido University of Education, Midorigaoka, Iwamizawa, Hokkaido, 068-8642, Japan suzuki.junichi@i.hokkyodai.ac.jp.
authors.forename: Junichi
authors.initials: J
authors.lastname: Suzuki
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000222:Adaptation, Physiological; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D004195:Disease Models, Animal; D005227:Fatty Acids / Q000378:metabolism*; D000860:Hypoxia / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008813:Mice, Inbred ICR; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000503:physiopathology; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010807:Physical Endurance; D005082:Physical Exertion; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D035683:MicroRNAs; C522604:Mirn16 microRNA, mouse; C534062:Mirn23b microRNA, mouse; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002334:Carnitine O-Palmitoyltransferase
keywords: Capillarization; exercise training; fatty acid metabolism; intermittent hypoxia; microRNA