Compared effects of hindlimb unloading versus terrestrial deafferentation on muscular properties of the rat soleus

Picquet, Florence

doi:10.1016/s0014-4886(03)00111-0

Cited by 40 publications

(28 citation statements)

References 38 publications

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“…Short durations of hindlimb suspension (7-10 days) have been reported to induce atrophy ranging from 30 to 48% in soleus muscle fibers (10,61), and our ABM generated 30 -40% atrophy at this time point. Atrophy levels have been reported to vary between 33 and 60% by day 14 (10,29,40,47,51), and the prediction of our ABM of 51% resides within this range (Fig. 3).…”

Section: Discussionsupporting

confidence: 67%

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Martin

Blemker

Peirce

2015

Journal of Applied Physiology

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Martin KS, Blemker SS, Peirce SM. Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy. J Appl Physiol 118: 1299 -1309, 2015. First published February 26, 2015 doi:10.1152/japplphysiol.01150.2014.-Skeletal muscle is highly responsive to use. In particular, muscle atrophy attributable to decreased activity is a common problem among the elderly and injured/ immobile. However, each muscle does not respond the same way. We developed an agent-based model that generates a tissue-level skeletal muscle response to disuse/immobilization. The model incorporates tissue-specific muscle fiber architecture parameters and simulates changes in muscle fiber size as a result of disuse-induced atrophy that are consistent with published experiments. We created simulations of 49 forelimb and hindlimb muscles of the rat by incorporating eight fiber-type and size parameters to explore how these parameters, which vary widely across muscles, influence sensitivity to disuse-induced atrophy. Of the 49 muscles modeled, the soleus exhibited the greatest atrophy after 14 days of simulated immobilization (51% decrease in fiber size), whereas the extensor digitorum communis atrophied the least (32%). Analysis of these simulations revealed that both fibertype distribution and fiber-size distribution influence the sensitivity to disuse atrophy even though no single tissue architecture parameter correlated with atrophy rate. Additionally, software agents representing fibroblasts were incorporated into the model to investigate cellular interactions during atrophy. Sensitivity analyses revealed that fibroblast agents have the potential to affect disuse-induced atrophy, albeit with a lesser effect than fiber type and size. In particular, muscle atrophy elevated slightly with increased initial fibroblast population and increased production of TNF-␣. Overall, the agent-based model provides a novel framework for investigating both tissue adaptations and cellular interactions in skeletal muscle during atrophy. agent-based model; muscle atrophy; fiber type; tissue architecture; fibroblasts SKELETAL MUSCLE ADAPTS to activity levels, where elevated activity leads to increases in muscle size (muscle hypertrophy) and diminished activity levels lead to decreases in muscle size (muscle atrophy) (6, 36).1 Muscle atrophy is estimated to affect 45% of the U.S. elderly population and directly attributed to 1.5% of total direct healthcare costs in 2000 ($18.5 billion) (25). In young people, diminished activity as a consequence of surgery-related immobilization (2, 68), bed rest (33), or long-term mechanical ventilation (34) lead to disabling muscle weakness.Muscle atrophy, triggered by loss of mechanical stimulation, causes changes in the behavior of the various cell types that comprise muscle tissue (52, 53). Muscle fiber protein production decreases in the absence of mechanical stimulation (46), and protein breakdown transiently increases then diminishes during disuse (46); both of these responses are likely dependent ...

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Section: Discussionsupporting

confidence: 67%

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Martin

Blemker

Peirce

2015

Journal of Applied Physiology

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“…Studies performed using animal models of hindlimb unloading showed that there is a shift of MHC isoforms from slow to fast, accompanied by significant muscle atrophy (Leterme and Falempin, 1994; Picquet and Falempin, 2003). It is noteworthy that chronic electrostimulation prevented the shift in fiber types, but failed to counteract the loss of muscle mass and force output (Leterme and Falempin, 1994).…”

Section: Effects Of Physical Inactivity On Muscle Fatiguementioning

confidence: 99%

Effects of Physical Activity and Inactivity on Muscle Fatigue

Bogdanis¹

2012

Front. Physio.

256

197

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The aim of this review was to examine the mechanisms by which physical activity and inactivity modify muscle fatigue. It is well known that acute or chronic increases in physical activity result in structural, metabolic, hormonal, neural, and molecular adaptations that increase the level of force or power that can be sustained by a muscle. These adaptations depend on the type, intensity, and volume of the exercise stimulus, but recent studies have highlighted the role of high intensity, short-duration exercise as a time-efficient method to achieve both anaerobic and aerobic/endurance type adaptations. The factors that determine the fatigue profile of a muscle during intense exercise include muscle fiber composition, neuromuscular characteristics, high energy metabolite stores, buffering capacity, ionic regulation, capillarization, and mitochondrial density. Muscle fiber-type transformation during exercise training is usually toward the intermediate type IIA at the expense of both type I and IIx myosin heavy-chain isoforms. High-intensity training results in increases of both glycolytic and oxidative enzymes, muscle capillarization, improved phosphocreatine resynthesis and regulation of K+, H+, and lactate ions. Decreases of the habitual activity level due to injury or sedentary lifestyle result in partial or even compete reversal of the adaptations due to previous training, manifested by reductions in fiber cross-sectional area, decreased oxidative capacity, and capillarization. Complete immobilization due to injury results in markedly decreased force output and fatigue resistance. Muscle unloading reduces electromyographic activity and causes muscle atrophy and significant decreases in capillarization and oxidative enzymes activity. The last part of the review discusses the beneficial effects of intermittent high-intensity exercise training in patients with different health conditions to demonstrate the powerful effect of exercise on health and well being.

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“…3: lane 5). We were able to determine four MHC isoforms already described in our previous studies (26,27). According to their increasing order of electrophoretic mobility, in lane 5, fast MHC isoforms were identified as being MHC IIA, MHC IIX, MHC IIB, and slow MHC isoform as MHC I.…”

Section: Resultsmentioning

confidence: 83%

Changes in rat soleus muscle phenotype consecutive to a growth in hypergravity followed by normogravity

Picquet

Bouët²,

Cochon³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Picquet, F., V. Bouet, L. Cochon, M. Lacour, and M. Falempin. Changes in rat soleus muscle phenotype consecutive to a growth in hypergravity followed by normogravity. Am J Physiol Regul Integr Comp Physiol 289: R217-R224, 2005. First published March 17, 2005; doi:10.1152/ajpregu.00596.2004.-It has been demonstrated that a long-term stay in hypergravity (HG: 2G) modified the phenotype and the contractile properties of rat soleus muscle. The ability of this muscle to contract was drastically reduced, which is a sign of anticipated aging. Consequently, our aim was to determine whether rats conceived, born, and reared in hypergravity showed adaptative capacities in normogravity (NG: 1G). This study was performed on rats divided into two series: the first was reared in HG until 100 days and was submitted to normogravity until 115 to 220 postnatal days (HG-NG rats); the second was made up of age paired groups reared in normogravity (NG rats). The contractile, morphological, and phenotypical properties of soleus muscle were studied. Our results showed that the NG rats were characterized by coexpressions of slow and fast myosin, respectively, 76.5 and 23.5% at 115 days. During their postnatal maturation, the fast isoform was gradually replaced by slow myosin. At 220 days, the relative proportions were respectively 91.05% and 8.95%. From 115 to 220 days, the HG-NG rats expressed 100% of slow myosin isoform and they presented a slower contractile behavior compared with their age-matched groups; at 115 days, the whole muscle contraction time was increased by 35%, and by 15%, at 220 days. Our study underlined the importance of gravity in the muscular development and suggested the existence of critical periods in muscle phenotype installation. muscular properties; myosin transition; gravity change; hindlimb muscle ALL LIVING ORGANISMS ARE DIRECTLY under the influence of a common and constant factor, gravity. It is well known that the development and the maturation of numerous life systems such as cell division, axonal growth, posture, and body movements are directly regulated by this factor (6,14,15,16).The effects of real (spaceflight) and simulated (hypodynamia-hypokinesia model, HH) microgravity on the neuromuscular system are well documented. In hindlimb muscles, an exposure to a HH period induces more marked effects in slow extensor muscles such as the soleus than in fast muscles (for a review, see Refs. 23 and 24). Most studies have been carried out in adult rats. Indeed, in soleus muscle from rats submitted to real and simulated microgravity, a muscular atrophy correlated to a decrease both in fiber and muscle cross-sectional area and to a decrease in muscle strength, which has been commonly described (for review, see Ref. 13). A slow-to-fast phenotype transition, characterized by changes in contractile protein isoforms such as myosin heavy and light chains (3, 32) and regulatory proteins (2), has also been reported. Moreover, the proprioceptive information could be disturbed (9), and a cortical reorganization has b...

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Compared effects of hindlimb unloading versus terrestrial deafferentation on muscular properties of the rat soleus

Cited by 40 publications

References 38 publications

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Agent-based computational model investigates muscle-specific responses to disuse-induced atrophy

Effects of Physical Activity and Inactivity on Muscle Fatigue

Changes in rat soleus muscle phenotype consecutive to a growth in hypergravity followed by normogravity

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