Intermittent hypobaric hypoxia combined with aerobic exercise improves muscle morphofunctional recovery after eccentric exercise to exhaustion in trained rats

2017 ◽  
Vol 122 (3) ◽  
pp. 580-592 ◽  
Author(s):  
D. Rizo-Roca ◽  
J. G. Ríos-Kristjánsson ◽  
C. Núñez-Espinosa ◽  
E. Santos-Alves ◽  
I. O. Gonçalves ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Muscle Damage ◽  
Eccentric Exercise ◽  
Hypobaric Hypoxia ◽  
Citrate Synthase ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Cross Sectional ◽  
Hypoxia Exposure ◽  
Intermittent Hypobaric Hypoxia

Unaccustomed eccentric exercise leads to muscle morphological and functional alterations, including microvasculature damage, the repair of which is modulated by hypoxia. We present the effects of intermittent hypobaric hypoxia and exercise on recovery from eccentric exercise-induced muscle damage (EEIMD). Soleus muscles from trained rats were excised before (CTRL) and 1, 3, 7, and 14 days after a double session of EEIMD protocol. A recovery treatment consisting of one of the following protocols was applied 1 day after the EEIMD: passive normobaric recovery (PNR), a 4-h daily exposure to passive hypobaric hypoxia at 4,000 m (PHR), or hypobaric hypoxia exposure followed by aerobic exercise (AHR). EEIMD produced an increase in the percentage of abnormal fibers compared with CTRL, and it affected the microvasculature by decreasing capillary density (CD, capillaries per mm2) and the capillary-to-fiber ratio (CF). After 14 days, AHR exhibited CD and CF values similar to those of CTRL animals (789 and 3.30 vs. 746 and 3.06) and significantly higher than PNR (575 and 2.62) and PHR (630 and 2.92). Furthermore, VEGF expression showed a significant 43% increase in AHR when compared with PNR. Moreover, after 14 days, the muscle fibers in AHR had a more oxidative phenotype than the other groups, with significantly smaller cross-sectional areas (AHR, 3,745; PNR, 4,502; and PHR, 4,790 µm2), higher citrate synthase activity (AHR, 14.8; PNR, 13.1; and PHR, 12 µmol·min−1·mg−1) and a significant 27% increment in PGC-1α levels compared with PNR. Our data show that hypoxia combined with exercise attenuates or reverses the morphofunctional alterations induced by EEIMD. NEW & NOTEWORTHY Our study provides new insights into the use of intermittent hypobaric hypoxia combined with exercise as a strategy to recover muscle damage induced by eccentric exercise. We analyzed the effects of hypobaric exposure combined with aerobic exercise on histopathological features of muscle damage, fiber morphofunctionality, capillarization, angiogenesis, and the oxidative capacity of damaged soleus muscle. Most of these parameters were improved after a 2-wk protocol of intermittent hypobaric hypoxia combined with aerobic exercise.

scholarly journals Modulation of mitochondrial biomarkers by intermittent hypobaric hypoxia and aerobic exercise after eccentric exercise in trained rats

2017 ◽  
Vol 42 (7) ◽  
pp. 683-693 ◽  
Author(s):  
David Rizo-Roca ◽  
Juan Gabriel Ríos-Kristjánsson ◽  
Cristian Núñez-Espinosa ◽  
Estela Santos-Alves ◽  
José Magalhães ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Muscle Damage ◽  
Eccentric Exercise ◽  
Hypobaric Hypoxia ◽  
Citrate Synthase ◽  
Complex Iv ◽  
Intermittent Hypobaric Hypoxia ◽  
Mitochondrial Alterations ◽  
Recovery Protocols ◽  
Exercise Induced

Unaccustomed eccentric contractions induce muscle damage, calcium homeostasis disruption, and mitochondrial alterations. Since exercise and hypoxia are known to modulate mitochondrial function, we aimed to analyze the effects on eccentric exercise-induced muscle damage (EEIMD) in trained rats using 2 recovery protocols based on: (i) intermittent hypobaric hypoxia (IHH) and (ii) IHH followed by exercise. The expression of biomarkers related to mitochondrial biogenesis, dynamics, oxidative stress, and bioenergetics was evaluated. Soleus muscles were excised before (CTRL) and 1, 3, 7, and 14 days after an EEIMD protocol. The following treatments were applied 1 day after the EEIMD: passive normobaric recovery (PNR), 4 h daily exposure to passive IHH at 4000 m (PHR) or IHH exposure followed by aerobic exercise (AHR). Citrate synthase activity was reduced at 7 and 14 days after application of the EEIMD protocol. However, this reduction was attenuated in AHR rats at day 14. PGC-1α and Sirt3 and TOM20 levels had decreased after 1 and 3 days, but the AHR group exhibited increased expression of these proteins, as well as of Tfam, by the end of the protocol. Mfn2 greatly reduced during the first 72 h, but returned to basal levels passively. At day 14, AHR rats had higher levels of Mfn2, OPA1, and Drp1 than PNR animals. Both groups exposed to IHH showed a lower p66shc(ser36)/p66shc ratio than PNR animals, as well as higher complex IV subunit I and ANT levels. These results suggest that IHH positively modulates key mitochondrial aspects after EEIMD, especially when combined with aerobic exercise.

Long-term isoprenaline administration produces an increase in capillarity in the soleus muscle of the rat

1987 ◽  
Vol 65 (3) ◽  
pp. 303-306 ◽  
Author(s):  
A. H. Sillau ◽  
Maria De Lourdes Philippi
Keyword(s):  
Soleus Muscle ◽  
Cross Sections ◽  
Citrate Synthase ◽  
Lactic Dehydrogenase ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Adrenergic Stimulation ◽  
Cross Sectional

The effects of isoprenaline administration (300 μg/kg for 5 weeks) on rat soleus muscle capillarity and glycolytic and oxidative capacities were evaluated. The treatment resulted in ventricular hypertrophy. The activities of lactic dehydrogenase, pyruvate kinase, citrate synthase, and cytochrome c oxidase in soleus muscle homogenates were not different between control and isoprenaline-injected animals. Capillaries were visualized in muscle cross sections treated to demonstrate ATPase activity after acid preincubation. Capillary density was higher in the experimental (873 ± 38 capillaries/mm2) than in the control (713 ± 33 capillaries/mm2) animals. Capillary to fiber ratio was also higher in the experimental (2.47 ± 0.10) than in control (2.09 ± 0.08) animals, but fiber cross-sectional area was not changed by the treatment (2836 ± 87 μm2 in controls and 2951 ± 136 μm2 in experimental). A plot of capillary to fiber ratio vs. fiber cross-sectional area showed that at a given fiber cross-sectional area the value of capillary to fiber ratio of the treated animals was higher than that of the controls. This indicates that treatment resulted in the proliferation of microvessels. The results suggest that prolonged β-adrenergic stimulation results in the development of new capillaries but that this is not accompanied by increases in the oxidative capacity of the soleus muscle of the rat.

Exercise-induced cellular alterations in the diaphragm

1992 ◽  
Vol 263 (5) ◽  
pp. R1093-R1098 ◽  
Author(s):  
S. K. Powers ◽  
D. Criswell ◽  
F. K. Lieu ◽  
S. Dodd ◽  
H. Silverman
Keyword(s):  
Exercise Training ◽  
Endurance Training ◽  
Fiber Type ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Control Group ◽  
Type I ◽  
Fiber Types ◽  
Image Analysis System ◽  
Cross Sectional

Limited data exist concerning the effects of exercise training on cellular oxidative capacity in the diaphragm of senescent animals. In this study we examined the changes in cellular oxidative capacity, muscle cell cross-sectional area (CSA), and capillarity within the costal diaphragm of senescent animals after a 10-wk endurance-training program. Twelve 24-mo-old female Fischer 344 rats were divided into either a sedentary control group (n = 6) or exercise training group (n = 6). The trained animals exercised on a motor-driven treadmill (60 min/day, 5 days/wk) at a work rate equal to approximately 55-65% VO2max. Capillaries were identified histologically and fiber types determined using adenosinetriphosphatase (ATPase) histochemistry. Succinate dehydrogenase (SDH) activity and CSA in individual fibers were measured using a computerized image analysis system. Exercise training did not increase (P > 0.05) the capillary-to-fiber ratio for any fiber type. However, training significantly decreased CSA (P < 0.05) and increased capillary density (capillary number/CSA) (P < 0.05) in type I, type IIa, and type IIb fibers. Furthermore, exercise training resulted in small but significant increase in SDH activity (P < 0.05) in type I and IIa fibers, whereas training did not alter SDH activity (P > 0.05) in type IIb fibers. These data demonstrate that endurance training in senescent animals results in small relative improvements in both oxidative capacity and capillary density in costal diaphragmatic type I and IIa muscle fibers. The increase in both capillary density and fiber SDH activity was largely due to a reduction in fiber CSA.

Metabolic responses of muscle to exercise

2004 ◽  
Vol 32 ◽  
pp. 1-9
Author(s):  
B Essén–Gustavsson
Keyword(s):  
Treadmill Exercise ◽  
Metabolic Response ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Metabolic Responses ◽  
Type I ◽  
Cross Sectional ◽  
Fibre Type Composition ◽  
Metabolic Properties ◽  
Biochemical Analyses

AbstractMuscle is a tissue with a great plasticity due to the fact that it is composed of fibres having different contractile and metabolic properties. In horses, muscle metabolic responses to exercise are studied by taking biopsies from the gluteus medius muscle. Histochemical stains are used to identify slow contracting type I fibres and fast contracting type IIA and type IIB fibres and to evaluate fibre areas, capillary supply, oxidative capacity, glycogen and lipid content in a muscle. Biochemical analyses of substrates, metabolites and enzyme activities are performed either on a whole piece of muscle, on pools of fibres or on single fibres of identified type.All fibres contain glycogen whereas lipid is mainly found in type I and type IIA fibres that have smaller cross–sectional areas and a higher oxidative capacity than type IIB fibres. Large variations can be seen in metabolic profile between and within fibre types. The most common muscular adaptation to training is an increase in oxidative capacity, capillary density and an increase in the type IIA/IIB ratio. The order of recruitment of fibres during most types of exercise is from type I to type IIA and type IIB.The higher the intensity of exercise, the faster is the breakdown of glycogen. After racing (1640-2640m), and after high intense treadmill exercise, concentrations of lactate and inosine monophosphate (IMP) are increased in the muscle and concentrations of glycogen, adenosine triphosphate (ATP) and creatine phosphate (CP) decreased. Extremely low ATP and high IMP concentrations especially in some type II fibres are observed after racing.After exercise of low intensity and long duration glycogen and triglyceride stores in muscle are utilised, amino acid metabolism is enhanced and protein degradation may occur. After submaximal treadmill exercise to fatigue and after endurance rides glycogen is degraded and depletion occurs mainly in type I and type IIA fibres.Fibre type composition, substrate sources and differences in metabolic properties among fibres and the extent to which fibres are recruited are all factors that influence the metabolic responses of muscle to exercise. Biochemical analyses on whole muscle must be interpreted with caution since large variations in metabolic response to exercise occur among different fibres.

Contribution of central and peripheral adaptations to changes in maximal oxygen uptake following 4 weeks of sprint interval training

2018 ◽  
Vol 43 (10) ◽  
pp. 1059-1068 ◽  
Author(s):  
James P. Raleigh ◽  
Matthew D. Giles ◽  
Hashim Islam ◽  
Matthew Nelms ◽  
Robert F. Bentley ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Citrate Synthase ◽  
Interval Training ◽  
Maximal Activity ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Sprint Interval Training ◽  
Peripheral Arterial

The current study examined the contribution of central and peripheral adaptations to changes in maximal oxygen uptake (V̇O2max) following sprint interval training (SIT). Twenty-three males completed 4 weekly SIT sessions (8 × 20-s cycling bouts at ∼170% of work rate at V̇O2max, 10-s recovery) for 4 weeks. Following completion of training, the relationship between changes in V̇O2max and changes in central (cardiac output) and peripheral (arterial–mixed venous oxygen difference (a-vO2diff), muscle capillary density, oxidative capacity, fibre-type distribution) adaptations was determined in all participants using correlation analysis. Participants were then divided into tertiles on the basis of the magnitude of their individual V̇O2max responses, and differences in central and peripheral adaptations were examined in the top (HI; ∼10 mL·kg−1·min−1 increase in V̇O2max, p < 0.05) and bottom (LO; no change in V̇O2max, p > 0.05) tertiles (n = 8 each). Training had no impact on maximal cardiac output, and no differences were observed between the LO group and the HI group (p > 0.05). The a-vO2diff increased in the HI group only (p < 0.05) and correlated significantly (r = 0.71, p < 0.01) with changes in V̇O2max across all participants. Muscle capillary density (p < 0.02) and β-hydroxyacyl-CoA dehydrogenase maximal activity (p < 0.05) increased in both groups, with no between-group differences (p > 0.05). Citrate synthase maximal activity (p < 0.01) and type IIA fibre composition (p < 0.05) increased in the LO group only. Collectively, although the heterogeneity in the observed V̇O2max response following 4 weeks of SIT appears to be attributable to individual differences in systemic vascular and/or muscular adaptations, the markers examined in the current study were unable to explain the divergent V̇O2max responses in the LO and HI groups.

Increased oxidative capacity does not protect skeletal muscle fibers from eccentric contraction-induced injury

1998 ◽  
Vol 274 (5) ◽  
pp. R1300-R1308 ◽  
Author(s):  
T. J. Patel ◽  
D. Cuizon ◽  
O. Mathieu-Costello ◽  
J. Fridén ◽  
R. L. Lieber
Keyword(s):  
Electrical Stimulation ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Exercise Bout ◽  
Eccentric Contraction ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Training Effect ◽  
Muscle Oxidative Capacity ◽  
Tetanic Tension

Isometric electrical stimulation was delivered to rabbit dorsiflexor muscles at 10 Hz for 1 s on and 1 s off over 30 min, 5 days/wk for 3 wk to induce an increase in muscle oxidative capacity. Stimulation-trained muscles as well as untrained muscles were then subjected to a 30-min eccentric exercise bout to test whether increased oxidative capacity provided a protective effect against muscle injury. Electrical stimulation resulted in significant training of both the extensor digitorum longus (EDL) and tibialis anterior (TA) muscles, with EDL citrate synthase (CS) activity increasing an average of 67% ( P < 0.0001) and TA CS activity increasing by 27% ( P < 0.05). For all parameters measured, the magnitude of change was much greater for EDL than for TA muscle. Dorsiflexor fatigability decreased significantly during the 3-wk training period ( P < 0.0001), whereas the EDL and TA individually showed strong decreasing trends in fatigability after training. TA and EDL capillary density measured histomorphometrically increased from 839 ± 56 to 1,026 ± 71 mm−2( P = 0.07) and from 589 ± 37 to 792 ± 66 mm−2( P < 0.05), respectively. TA and EDL capillary-to-fiber ratio increased from 1.32 ± 0.10 to 1.55 ± 0.16 ( P > 0.2) and 1.08 ± 0.07 to 1.36 ± 0.14 ( P > 0.1), respectively. Type 2A fiber type percentage increased after stimulation training by 68% ( P < 0.0001) for the EDL and by 32% ( P > 0.1) for the TA at the expense of type 2D fibers. Despite the large training effect for the EDL and the modest training effect for the TA, no differences were observed between stimulation-trained and untrained groups for maximum dorsiflexion torque ( P > 0.3) or maximum tetanic tension ( P > 0.3) after eccentric contraction-induced injury. Additionally, no significant correlation was observed between CS activity and maximum tetanic tension after eccentric contraction-induced injury for either muscle ( P > 0.2). Thus we conclude that increasing muscle oxidative capacity by isometric electrical stimulation training did not protect muscle against eccentric contraction-induced injury.

scholarly journals Mechanisms of Cardiovascular Protection Associated with Intermittent Hypobaric Hypoxia Exposure in a Rat Model: Role of Oxidative Stress

2018 ◽  
Vol 19 (2) ◽  
pp. 366 ◽  
Author(s):  
Miguel Aguilar ◽  
Alejandro González-Candia ◽  
Jorge Rodríguez ◽  
Catalina Carrasco-Pozo ◽  
Daniel Cañas ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Rat Model ◽  
Hypobaric Hypoxia ◽  
Cardiovascular Protection ◽  
Hypoxia Exposure ◽  
Intermittent Hypobaric Hypoxia

scholarly journals Fiber Composition and Oxidative Capacity of Hamster Skeletal Muscle

2002 ◽  
Vol 50 (12) ◽  
pp. 1685-1692 ◽  
Author(s):  
John P. Mattson ◽  
Todd A. Miller ◽  
David C. Poole ◽  
Michael D. Delp
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Rank Order ◽  
Oxidative Capacity ◽  
Type I ◽  
Cross Sectional ◽  
Physiological Investigation ◽  
Combining Data ◽  
Type I Fibers

The hamster is a valuable biological model for physiological investigation. Despite the obvious importance of the integration of cardiorespiratory and muscular system function, little information is available regarding hamster muscle fiber type and oxidative capacity, both of which are key determinants of muscle function. The purpose of this investigation was to measure immunohistochemically the relative composition and size of muscle fibers composed of types I, IIA, IIX, and IIB fibers in hamster skeletal muscle. The oxidative capacity of each muscle was also assessed by measuring citrate synthase activity. Twenty-eight hindlimb, respiratory, and facial muscles or muscle parts from adult (144–147 g bw) male Syrian golden hamsters ( n=3) were dissected bilaterally, weighed, and frozen for immunohistochemical and biochemical analysis. Combining data from all 28 muscles analyzed, type I fibers made up 5% of the muscle mass, type IIA fibers 16%, type IIX fibers 39%, and type IIB fibers 40%. Mean fiber cross-sectional area across muscles was 1665 ± 328 μm2 for type I fibers, 1900 ± 417 μm2 for type IIA fibers, 3230 ± 784 μm2 for type IIX fibers, and 4171 ± 864 μm2 for type IIB fibers. Citrate synthase activity was most closely related to the population of type IIA fibers ( r=0.68, p<0.0001) and was in the rank order of type IIA > I > IIX > IIB. These data demonstrate that hamster skeletal muscle is predominantly composed of type IIB and IIX fibers.

Fiber hypertrophy and increased oxidative capacity can occur simultaneously in pig glycolytic skeletal muscle

2014 ◽  
Vol 306 (4) ◽  
pp. C354-C363 ◽  
Author(s):  
T. L. Scheffler ◽  
J. M. Scheffler ◽  
S. Park ◽  
S. C. Kasten ◽  
Y. Wu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Citrate Synthase ◽  
Oxidative Capacity ◽  
Mitochondrial Proteins ◽  
Cross Sectional ◽  
Pig Muscle ◽  
Ryanodine Receptor 1 ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Amp Activated Protein Kinase

An inverse relationship between skeletal muscle fiber cross-sectional area (CSA) and oxidative capacity suggests that muscle fibers hypertrophy at the expense of oxidative capacity. Therefore, our objective was to utilize pigs possessing mutations associated with increased oxidative capacity [AMP-activated protein kinase (AMPKγ3R200Q)] or fiber hypertrophy [ryanodine receptor 1 (RyR1R615C)] to determine if these events occur in parallel. Longissimus muscle was collected from wild-type (control), AMPKγ3R200Q, RyR1R615C, and AMPKγ3R200Q-RyR1R615Cpigs. Regardless of AMPK genotype, RyRR615Cincreased fiber CSA by 35%. In contrast, AMPKγ3R200Qpig muscle exhibited greater citrate synthase and β-hydroxyacyl CoA dehydrogenase activity. Isolated mitochondria from AMPKγ3R200Qmuscle had greater maximal, ADP-stimulated oxygen consumption rate. Additionally, AMPKγ3R200Qmuscle contained more (∼50%) of the mitochondrial proteins succinate dehydrogenase and cytochrome c oxidase and more mitochondrial DNA. Surprisingly, RyR1R615Cincreased mitochondrial proteins and DNA, but this was not associated with improved oxidative capacity, suggesting that altered energy metabolism in RyR1R615Cmuscle influences mitochondrial proliferation and protein turnover. Thus pigs that possess both AMPKγ3R200Qand RyRR615Cexhibit increased muscle fiber CSA as well as greater oxidative capacity. Together, our findings support the notion that hypertrophy and enhanced oxidative capacity can occur simultaneously in skeletal muscle and suggest that the signaling mechanisms controlling these events are independently regulated.

Effects of chronic intermittent hypobaric hypoxia on prostate-specific antigen (PSA) in Chilean miners

2021 ◽  
pp. oemed-2020-107232
Author(s):  
Diana Elizabeth Alcantara-Zapata ◽  
Shrikant I Bangdiwala ◽  
Daniel Jiménez ◽  
Manolis Kogevinas ◽  
Nella Marchetti ◽  
...  
Keyword(s):  
Prostate Specific Antigen ◽  
Hypobaric Hypoxia ◽  
Multilevel Models ◽  
Specific Antigen ◽  
Mining Operation ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Mixed Effect ◽  
Intermittent Hypobaric Hypoxia ◽  
Different Altitudes

ObjectiveThe aim was to determine the effects of chronic intermittent hypobaric hypoxia (CIHH) on prostate-specific antigen (PSA) levels in Chilean miners who work at different altitudes.MethodsA cross-sectional study was conducted between April and July 2019. Miners from five mines (N=338) at different altitudes were evaluated. We recorded sociodemographic, working and altitude information. Haemoglobin oxygen saturation (SaO2) and haemoglobin (Hb) were measured in situ, while PSA and testosterone were analysed at a low level. Linear mixed-effect models were used to evaluate the association between PSA level and two CIHH exposures: composite CIHH (with four descriptors) and ChileStd-CIHH (CIHH Chilean standard; based on the Chilean technical guide for occupational exposure to CIHH). All models were adjusted by age, body mass index and day of the work the samples were taken.ResultsHighest and lowest PSA levels were found in mines ≥3000 m above sea level (mine 3: median=0.75, IQR=−0.45; mine 4: median=0.46, IQR=−0.35). In the multilevel models, the wider altitude difference between mining operation and camp showed lower PSA levels (model D: βPSA=−0.93 ng/mL, βlogPSA=−0.07, p<0001), adjusted for other CIHH descriptors, SaO2, Hb and testosterone. The descriptors of composite CIHH explained better PSA variations than ChileStd-CIHH (model D: marginal R2=0.090 vs model A: marginal R2=0.016).ConclusionsOccupational health regulations and high altitude medicine should consider these results as initial evidence on the inclusion of new descriptors for CIHH and the possible effect of this exposure on PSA levels in this male-dominated occupational sector.

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