Ultrastructural evidence for disuse atrophy in insect skeletal muscle

1979 ◽  
Vol 203 (3) ◽  
Author(s):  
M. Anderson
Keyword(s):  
Skeletal Muscle ◽  
Disuse Atrophy ◽  
Ultrastructural Evidence ◽  
Insect Skeletal Muscle

scholarly journals Skeletal muscle PGC-1β signaling is sufficient to drive an endurance exercise phenotype and to counteract components of detraining in mice

2017 ◽  
Vol 312 (5) ◽  
pp. E394-E406 ◽  
Author(s):  
Samuel Lee ◽  
Teresa C. Leone ◽  
Lisa Rogosa ◽  
John Rumsey ◽  
Julio Ayala ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Early Stage ◽  
Peroxisome Proliferator ◽  
Disuse Atrophy ◽  
Proof Of Concept ◽  
Peroxisome Proliferator Activated Receptor ◽  
Muscle Disuse ◽  
Training Response

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and -1β serve as master transcriptional regulators of muscle mitochondrial functional capacity and are capable of enhancing muscle endurance when overexpressed in mice. We sought to determine whether muscle-specific transgenic overexpression of PGC-1β affects the detraining response following endurance training. First, we established and validated a mouse exercise-training-detraining protocol. Second, using multiple physiological and gene expression end points, we found that PGC-1β overexpression in skeletal muscle of sedentary mice fully recapitulated the training response. Lastly, PGC-1β overexpression during the detraining period resulted in partial prevention of the detraining response. Specifically, an increase in the plateau at which O2 uptake (V̇o2) did not change from baseline with increasing treadmill speed [peak V̇o2 (ΔV̇o2max)] was maintained in trained mice with PGC-1β overexpression in muscle 6 wk after cessation of training. However, other detraining responses, including changes in running performance and in situ half relaxation time (a measure of contractility), were not affected by PGC-1β overexpression. We conclude that while activation of muscle PGC-1β is sufficient to drive the complete endurance phenotype in sedentary mice, it only partially prevents the detraining response following exercise training, suggesting that the process of endurance detraining involves mechanisms beyond the reversal of muscle autonomous mechanisms involved in endurance fitness. In addition, the protocol described here should be useful for assessing early-stage proof-of-concept interventions in preclinical models of muscle disuse atrophy.

Differing mechanisms of cold-induced changes in capillary supply in m. tibialis anterior of rats and hamsters

2002 ◽  
Vol 205 (6) ◽  
pp. 829-840 ◽  
Author(s):  
Durmus Deveci ◽  
Stuart Egginton
Keyword(s):  
Skeletal Muscle ◽  
Cold Acclimation ◽  
Oxygen Diffusion ◽  
Tibialis Anterior ◽  
Capillary Density ◽  
Disuse Atrophy ◽  
Diffusion Distance ◽  
Capillary Supply ◽  
Fibre Size ◽  
Anatomical Adaptations

SUMMARY The physiological, metabolic and anatomical adaptations of skeletal muscle to chronic cold exposure were investigated in Wistar rats (Rattus norvegicus), a species that defends core temperature, and Syrian hamsters (Mesocricetus auratus), which may adopt a lower set point under unfavourable conditions. Animals were exposed to a simulated onset of winter in an environmental chamber, progressively shortening photoperiod and reducing temperature from 12 h:12 h L:D and 22°C to 1 h:23 h L:D and 5°C over 4 weeks. The animals were left at 4°C for a further 4 weeks to complete the process of cold-acclimation. M. tibialis anterior from control (euthermic) and cold-acclimated animals of similar mass showed a significant hyperactivity-induced hypertrophy in the rat, but a small disuse atrophy in the hamster. Little evidence was found for interconversion among fibre types in skeletal muscle on cold-acclimation, and only modest differences were seen in activity of oxidative or glycolytic enzymes in either species. However, adjustments in Type II fibre size paralleled the muscle hypertrophy in rat and atrophy in hamster. Cold-induced angiogenesis was present in the rat, averaging a 28 % increase in capillary-to-fibre ratio (C:F) but, as this was balanced by fibre hypertrophy across the whole muscle, there was no change in capillary density (CD). In contrast, the C:F was similar in both groups of hamsters, whereas CD rose by 33 % in line with fibre atrophy. Within distinct regions of the m. tibialis anterior, there was a correlation between angiogenesis and fibre size in rats, in which oxygen diffusion distance increased, but not in hamsters, in which there was a reduced oxygen diffusion distance. Consequently, the change in C:F was greatest (39 %) in the glycolytic cortex region of the m. tibialis anterior in rats. We conclude that non-hibernator and hibernator rodents improve peripheral oxygen transport following cold-acclimation by different mechanisms. In rats, an increase in fibre girth was accompanied by a true angiogenesis, while the improved apparent capillary supply in hamsters was due to smaller fibre diameters. These responses are consistent with the strategies of resisting and accommodating, respectively, an annual fall in environmental temperature.

scholarly journals Omega‐3 fatty acid supplementation attenuates skeletal muscle disuse atrophy during two weeks of unilateral leg immobilization in healthy young women

2019 ◽  
Vol 33 (3) ◽  
pp. 4586-4597 ◽  
Author(s):  
Chris Mcglory ◽  
Stefan H. M. Gorissen ◽  
Michael Kamal ◽  
Ravninder Bahniwal ◽  
Amy J. Hector ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Young Women ◽  
Disuse Atrophy ◽  
Omega 3 ◽  
Fatty Acid Supplementation ◽  
Acid Supplementation ◽  
Omega 3 Fatty Acid ◽  
Muscle Disuse

Skeletal muscle atrophy: disease-induced mechanisms may mask disuse atrophy

2015 ◽  
Vol 36 (6) ◽  
pp. 405-421 ◽  
Author(s):  
C. J. Malavaki ◽  
G. K. Sakkas ◽  
G. I. Mitrou ◽  
A. Kalyva ◽  
I. Stefanidis ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Skeletal Muscle Atrophy ◽  
Disuse Atrophy

Disuse Atrophy of Skeletal Muscle

1988 ◽  
Vol 16 ◽  
pp. 61???88 ◽  
Author(s):  
X. J. MUSACCHIA ◽  
JOSEPH M. STEFFEN ◽  
RONALD D. FELL
Keyword(s):  
Skeletal Muscle ◽  
Disuse Atrophy

Testosterone suppression does not exacerbate disuse atrophy and impairs muscle recovery that is not rescued by high protein

2020 ◽  
Vol 129 (1) ◽  
pp. 5-16 ◽  
Author(s):  
Erik D. Hanson ◽  
Andrew C. Betik ◽  
Cara A. Timpani ◽  
John Tarle ◽  
Xinmei Zhang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adverse Effects ◽  
Muscle Mass ◽  
Caloric Intake ◽  
Disuse Atrophy ◽  
Muscle Recovery ◽  
Testosterone Levels ◽  
Muscle Disuse ◽  
Low Testosterone ◽  
And Function

Low testosterone levels during skeletal muscle disuse did not worsen declines in muscle mass and function, although hypogonadism may attenuate recovery during subsequent reloading. Diets high in casein did not improve outcomes during immobilization or reloading. Practical strategies are needed that do not compromise caloric intake yet provide effective protein doses to augment these adverse effects.

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