scholarly journals Differential Response of Oxidative and Glycolytic Skeletal Muscle Fibers to Mesterolone

2021 ◽  
Author(s):  
Hasan A. Asfour ◽  
Emad I. Shaqoura ◽  
Raed S. Said ◽  
Ayman G. Mustafa ◽  
Bright Starling Emerald ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Domain Size ◽  
Muscle Weight ◽  
Skeletal Muscle Fibers ◽  
Age Related ◽  
Anterior Latissimus Dorsi ◽  
Immunocytochemical Techniques ◽  
Independent Effects ◽  
Androgenic Steroids

Abstract Background: Oxidative and glycolytic muscle fibers differ in their ultrastructure, metabolism, and responses to physiological stimuli and pathological insults. We examined whether these fibers respond differentially to exogenous anabolic androgenic steroids (AASs) by comparing morphological and histological changes between the oxidative anterior latissimus dorsi (ALD) and glycolytic pectoralis major (PM) fibers in adult avian muscles. Methods: Adult female White Leghorn chickens (Gallus gallus) were randomly divided into five groups: a vehicle control and four mesterolone treatment groups (4, 8, 12, and 16 mg/kg). Mesterolone was administered orally every three days for 4 weeks. Immunocytochemical techniques and morphometric analyses were employed to measure the changes in muscle weight, fiber size, satellite cell (SC) composition, and number of myonuclei. Results: Mesterolone increased both body and muscle weights and induced hypertrophy in glycolytic PM fibers but not in oxidative ALD fibers. Mesterolone induced SC proliferation in both muscles; however, the myonuclear accretion was noticeable only in the PM muscle. In both muscles, the collective changes maintained a constant myonuclear domain size and the changes were dose independent.Conclusion: Mesterolone induced distinct dose-independent effects in avian oxidative and glycolytic skeletal muscle fibers; these findings might be clinically valuable in the treatment of age-related sarcopenia.

scholarly journals Differential response of oxidative and glycolytic skeletal muscle fibers to mesterolone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hasan A. Asfour ◽  
Emad I. Shaqoura ◽  
Raed S. Said ◽  
Ayman G. Mustafa ◽  
Bright Starling Emerald ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Domain Size ◽  
Muscle Weight ◽  
Skeletal Muscle Fibers ◽  
Age Related ◽  
Anterior Latissimus Dorsi ◽  
Immunocytochemical Techniques ◽  
Independent Effects ◽  
Androgenic Steroids

AbstractOxidative and glycolytic muscle fibers differ in their ultrastructure, metabolism, and responses to physiological stimuli and pathological insults. We examined whether these fibers respond differentially to exogenous anabolic androgenic steroids (AASs) by comparing morphological and histological changes between the oxidative anterior latissimus dorsi (ALD) and glycolytic pectoralis major (PM) fibers in adult avian muscles. Adult female White Leghorn chickens (Gallus gallus) were randomly divided into five groups: a vehicle control and four mesterolone treatment groups (4, 8, 12, and 16 mg/kg). Mesterolone was administered orally every three days for four weeks. Immunocytochemical techniques and morphometric analyses were employed to measure the changes in muscle weight, fiber size, satellite cell (SC) composition, and number of myonuclei. Mesterolone increased both body and muscle weights and induced hypertrophy in glycolytic PM fibers but not in oxidative ALD fibers. Mesterolone induced SC proliferation in both muscles; however, the myonuclear accretion was noticeable only in the PM muscle. In both muscles, the collective changes maintained a constant myonuclear domain size and the changes were dose independent. In conclusion, mesterolone induced distinct dose-independent effects in avian oxidative and glycolytic skeletal muscle fibers; these findings might be clinically valuable in the treatment of age-related sarcopenia.

scholarly journals SIRT1 regulates nuclear number and domain size in skeletal muscle fibers

2018 ◽  
Vol 233 (9) ◽  
pp. 7157-7163 ◽  
Author(s):  
Jacob A. Ross ◽  
Yotam Levy ◽  
Kristoffer Svensson ◽  
Andrew Philp ◽  
Simon Schenk ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Domain Size ◽  
Skeletal Muscle Fibers ◽  
Nuclear Number

scholarly journals An investigation of p53 in skeletal muscle aging

2019 ◽  
Vol 127 (4) ◽  
pp. 1075-1084 ◽  
Author(s):  
Scott M. Ebert ◽  
Jason M. Dierdorff ◽  
David K. Meyerholz ◽  
Steven A. Bullard ◽  
Asma Al-Zougbi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Fibers ◽  
Skeletal Muscle Atrophy ◽  
P53 Expression ◽  
Skeletal Muscle Fibers ◽  
Age Related ◽  
Skeletal Muscle Aging ◽  
And Function

Age-related skeletal muscle atrophy is a very common and serious condition that remains poorly understood at the molecular level. Several lines of evidence have suggested that the tumor suppressor p53 may play a central, causative role in skeletal muscle aging, whereas other, apparently contradictory lines of evidence have suggested that p53 may be critical for normal skeletal muscle function. To help address these issues, we performed an aging study in male muscle-specific p53-knockout mice (p53 mKO mice), which have a lifelong absence of p53 expression in skeletal muscle fibers. We found that the absence of p53 expression in skeletal muscle fibers had no apparent deleterious or beneficial effects on skeletal muscle mass or function under basal conditions up to 6 mo of age, when mice are fully grown and exhibit peak muscle mass and function. Furthermore, at 22 and 25 mo of age, when age-related muscle weakness and atrophy are clearly evident in mice, p53 mKO mice demonstrated no improvement or worsening of skeletal muscle mass or function relative to littermate control mice. At advanced ages, p53 mKO mice began to die prematurely and had an increased incidence of osteosarcoma, precluding analyses of muscle mass and function in very old p53 mKO mice. In light of these results, we conclude that p53 expression in skeletal muscle fibers has minimal if any direct, cell autonomous effect on basal or age-related changes in skeletal muscle mass and function up to at least 22 mo of age. NEW & NOTEWORTHY Previous studies implicated the transcriptional regulator p53 as a potential mediator of age-related skeletal muscle weakness and atrophy. We tested this hypothesis by investigating the effect of aging in muscle-specific p53-knockout mice. Our results strongly suggest that p53 activity within skeletal muscle fibers is not required for age-related skeletal muscle atrophy or weakness.

Low proteasomal activity in fast skeletal muscle fibers is not associated with increased age-related oxidative damage

2019 ◽  
Vol 117 ◽  
pp. 45-52 ◽  
Author(s):  
Raquel Fernando ◽  
Cathleen Drescher ◽  
Stefanie Deubel ◽  
Tobias Jung ◽  
Mario Ost ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Oxidative Damage ◽  
Muscle Fibers ◽  
Fast Skeletal Muscle ◽  
Proteasomal Activity ◽  
Skeletal Muscle Fibers ◽  
Age Related

The “KIMWIPE” Effect in Ultra-Thin Cryosections

1985 ◽  
Vol 43 ◽  
pp. 458-459
Author(s):  
I. Taylor ◽  
P. Ingram ◽  
J.R. Sommer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Ice Crystals ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Thin Sections ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried ◽  
Ice Crystal Formation

In studying quick-frozen single intact skeletal muscle fibers for structural and microchemical alterations that occur milliseconds, and fractions thereof, after electrical stimulation, we have developed a method to compare, directly, ice crystal formation in freeze-substituted thin sections adjacent to all, and beneath the last, freeze-dried cryosections. We have observed images in the cryosections that to our knowledge have not been published heretofore (Figs.1-4). The main features are that isolated, sometimes large regions of the sections appear hazy and have much less contrast than adjacent regions. Sometimes within the hazy regions there are smaller areas that appear crinkled and have much more contrast. We have also observed that while the hazy areas remain still, the regions of higher contrast visibly contract in the beam, often causing tears in the sections that are clearly not caused by ice crystals (Fig.3, arrows).

Effect of External Calcium and other Divalent Cations on K+ Contractures in Denervated Slow Skeletal Muscle Fibers of the Frog

2019 ◽  
Author(s):  
Leonardo Hernández
Keyword(s):  
Skeletal Muscle ◽  
Binding Capacity ◽  
Divalent Cations ◽  
Muscle Fibers ◽  
Free Calcium ◽  
Slow Skeletal Muscle ◽  
Skeletal Muscle Fibers ◽  
Free Calcium Concentration ◽  
Chronic Denervation ◽  
Denervated Muscles

The influence of Ca2+ and other divalent cations on contractile responses of slow skeletal muscle fibers of the frog (Rana pipiens) under conditions of chronic denervation was investigated.Isometric tension was recorded from slow bundles of normal and denervated cruralis muscle in normal solution and in solutions with free calcium concentration solution or in solutions where other divalent cations (Sr2+, Ni2+, Co2+ or Mn2+) substituted for calcium. In the second week after nerve section, in Ca2+-free solutions, we observed that contractures (evoked from 40 to 80 mM-K+) of non-denervated muscles showed significantly higher tensions (p<0.05), than those from denervated bundles. Likewise, in solutions where calcium was substituted by all divalent cations tested, with exception of Mn2+, the denervated bundles displayed lower tension than non-denervated, also in the second week of denervation. In this case, the Ca2+ substitution by Sr2+ caused the higher decrease in tension, followed by Co2+ and Ni2+, which were different to non-denervated bundles, as the lowest tension was developed by Mn2+, followed by Co2+, and then Ni2+ and Sr2+. After the third week, we observed a recovery in tension. These results suggest that denervation altering the binding capacity to divalent cations of the voltage sensor.

scholarly journals Development of a human neuromuscular tissue-on-a-chip model on a 24-well-plate-format compartmentalized microfluidic device

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Kazuki Yamamoto ◽  
Nao Yamaoka ◽  
Yu Imaizumi ◽  
Takunori Nagashima ◽  
Taiki Furutani ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Microfluidic Device ◽  
Motor Neurons ◽  
Muscle Fibers ◽  
Three Dimensional ◽  
Tissue Model ◽  
Skeletal Muscle Fibers

A three-dimensional human neuromuscular tissue model that mimics the physically separated structures of motor neurons and skeletal muscle fibers is presented.

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