scholarly journals Histological aspects of skeletal muscle fibers splitting of C57BL/6NCrl mice

2020 ◽  
pp. 291-296 ◽  
Author(s):  
P. Makovický ◽  
P. Makovický
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Skeletal Muscles ◽  
Muscle Fibers ◽  
Rectus Femoris ◽  
Skeletal Muscle Fiber ◽  
Fiber Splitting ◽  
Muscular Fiber ◽  
Skeletal Muscle Fibers ◽  
Muscle Fiber Regeneration

The objective of the current study is to present data on the splitting of skeletal muscle fibers in C57BL/6NCrl mice. Skeletal muscles (m. rectus femoris (m. quadriceps femoris)) from 500 (250 ♀ and 250 ♂) C57BL/6NCrl mice in the 16th week of life were sampled during autopsy and afterwards standardly histologically processed. Results show spontaneous skeletal muscle fiber splitting which is followed by skeletal muscle fiber regeneration. One solitary skeletal muscle fiber is split, or is in contact with few localized splitting skeletal muscle fibers. Part of the split skeletal muscular fiber is phagocytosed, but the remaining skeletal muscular fiber splits are merged into one regenerating skeletal muscle fiber. Nuclei move from the periphery to the regenerating skeletal muscle fiber center during this process. No differences were observed between female and male mice and the morphometry results document <1 % skeletal muscle fiber splitting. If skeletal muscular fibers splitting occurs 5 %> of all skeletal muscular fibers, it is suggested to describe and calculate this in the final histopathological report.

scholarly journals Resveratrol regulates skeletal muscle fibers switching through the AdipoR1-AMPK-PGC-1α pathway

2019 ◽  
Vol 10 (6) ◽  
pp. 3334-3343 ◽  
Author(s):  
Qinyang Jiang ◽  
Xiaofang Cheng ◽  
Yueyue Cui ◽  
Qin Xia ◽  
Xueyu Yan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Underlying Mechanism ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Type ◽  
Skeletal Muscle Fibers

This study was conducted to investigate the effect and underlying mechanism of Resveratrol (RES) in regulating skeletal muscle fiber-type switching.

scholarly journals Hsp60 in Skeletal Muscle Fiber Biogenesis and Homeostasis: From Physical Exercise to Skeletal Muscle Pathology

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 224 ◽  
Author(s):  
Antonella Marino Gammazza ◽  
Filippo Macaluso ◽  
Valentina Di Felice ◽  
Francesco Cappello ◽  
Rosario Barone
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Pathological Condition ◽  
Treatment Options ◽  
Muscle Fibers ◽  
Mitochondrial Protein ◽  
Oxidative Capacity ◽  
Skeletal Muscle Fiber ◽  
Muscle Pathology ◽  
Skeletal Muscle Fibers

Hsp60 is a molecular chaperone classically described as a mitochondrial protein with multiple roles in health and disease, participating to the maintenance of protein homeostasis. It is well known that skeletal muscle is a complex tissue, rich in proteins, that is, subjected to continuous rearrangements, and this homeostasis is affected by many different types of stimuli and stresses. The regular exercise induces specific histological and biochemical adaptations in skeletal muscle fibers, such as hypertrophy and an increase of mitochondria activity and oxidative capacity. The current literature is lacking in information regarding Hsp60 involvement in skeletal muscle fiber biogenesis and regeneration during exercise, and in disease conditions. Here, we briefly discuss the functions of Hsp60 in skeletal muscle fibers during exercise, inflammation, and ageing. Moreover, the potential usage of Hsp60 as a marker for disease and the evaluation of novel treatment options is also discussed. However, some questions remain open, and further studies are needed to better understand Hsp60 involvement in skeletal muscle homeostasis during exercise and in pathological condition.

Skeletal muscle fiber splitting with weight-lifting exercise in rats

1980 ◽  
Vol 157 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Kwok-Wai Ho ◽  
R. R. Roy ◽  
C. D. Tweedle ◽  
W. W. Heusner ◽  
W. D. van Huss ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Skeletal Muscle Fiber ◽  
Weight Lifting ◽  
Fiber Splitting

Reduced Mg2+ inhibition of Ca2+ release in muscle fibers of pigs susceptible to malignant hyperthermia

1997 ◽  
Vol 272 (1) ◽  
pp. C203-C211 ◽  
Author(s):  
V. J. Owen ◽  
N. L. Taske ◽  
G. D. Lamb
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Malignant Hyperthermia ◽  
Ryanodine Receptor ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Inhibitory Effect ◽  
Fiber Bundles ◽  
Force Response ◽  
Skeletal Muscle Fibers

The inhibitory effect of myoplasmic Mg2+ on Ca2+ release from the sarcoplasmic reticulum (SR) was examined in mechanically skinned skeletal muscle fibers from pigs of different ryanodine-receptor (RyR) genotypes. In fibers from pigs homozygous for the normal RyR allele, the free Mg2+ concentration ([Mg2+]) had to be lowered from the normal resting level of 1 to approximately 0.1 mM to induce Ca2+ release and a force response. Fibers from pigs heterozygous or homozygous for the RyR allele associated with malignant hyperthermia (MH) needed only a smaller reduction in free [Mg2+] to induce Ca2+ release (reduction to 0.1-0.2 and > or = 0.2 mM, respectively). Dantrolene (20 microM) counteracted the effect of this reduced Mg2+ inhibition in MH muscle. The response of muscle fiber bundles to the caffeine-halothane contracture test in the three genotypes correlated well with the responsiveness of single fibers to reduced [Mg2+]. Thus the abnormal responsiveness of MH muscle to various stimuli may largely result from the reduced ability of myoplasmic Mg2+ to inhibit Ca2+ release from the SR.

Abstract 478: Connexin-43 Reduction Rescues Cardiac and Skeletal Muscle Pathology in a Novel Mouse Model of Duchenne Muscular Dystrophy Symptomatic Carriers

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Julie Nouet ◽  
Eric Himelman ◽  
Diego Fraidenraich
Keyword(s):  
Skeletal Muscle ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mouse Model ◽  
Muscle Fiber ◽  
Connexin 43 ◽  
Muscle Fibers ◽  
Skeletal Muscle Fiber ◽  
Muscle Pathology ◽  
Female Carriers

Duchenne muscular dystrophy (DMD) and its associated cardiomyopathy manifest in 8-10% of all female carriers however research remains male-centric. Although underrepresented, symptomatic females face the risk of cardiac, respiratory, and skeletal muscle problems. Basic research and clinical trials exclude female carriers therefore developments in treatment expose females to unknown safety and efficacy issues. The bottleneck is largely due to the absence of a faithful mouse model. To generate a mouse model, we injected mdx embryonic stem cells (ESCs) into wild-type (WT) blastocysts ( mdx /WT chimera). The cardiac and skeletal muscle phenotype recapitulates the same generated as a consequence of x-inactivation in human manifesting female patients. In the heart, mdx /WT chimeras develop fibrotic cardiomyopathy. In the skeletal muscle, we found evidence of fibrosis, inflammation and muscle weakness. We found that Connexin-43 (Cx43), the primary gap junctional protein in the heart, was pathologically enhanced and remodeled in mdx /WT chimeras. Cx43 was also enhanced in the dystrophic skeletal muscle. Genetic reduction of Cx43-copy number protected mdx /WT chimeras from cardiac and skeletal muscle fiber damage. The latter result was unexpected because Cx43 is not expressed in mature muscle fibers. Upon further investigation, Cx43 was localized to the mononuclear cells invading the interstitial space between dystrophic skeletal muscle fibers. Pathologically enhanced activity of Cx43 in mdx FACS-macrophages was observed via ethidium bromide uptake and the Cx43 hemichannel peptide mimetic, Gap19, inhibited Cx43 function in a dose-dependent manner. Because an excess of Cx43 has been associated with cell death, we believe that Cx43 reduction in invading mdx macrophages benefits the skeletal muscle of understudied DMD carriers, perhaps by a paracrine mechanism involving macrophage-skeletal muscle fiber communication.

Skeletal muscle fiber composition is related to adiposity and in vitro glucose transport rate in humans

1995 ◽  
Vol 268 (3) ◽  
pp. E453-E457 ◽  
Author(s):  
M. S. Hickey ◽  
J. O. Carey ◽  
J. L. Azevedo ◽  
J. A. Houmard ◽  
W. J. Pories ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Skeletal Muscle Fiber ◽  
Transport Rate ◽  
Control Group ◽  
Type I ◽  
Fiber Composition

The purpose of this study was to determine if a relationship exists among skeletal muscle fiber composition, adiposity, and in vitro muscle glucose transport rate in humans. Rectus abdominus muscle was obtained during elective abdominal surgery from nonobese control (n = 12), obese (n = 12), and obese non-insulin-dependent diabetes mellitus (NIDDM) patients (n = 10). The obese NIDDM group had a significantly lower percentage of type I muscle fibers (32.2 +/- 1.9%) than the obese group (40.4 +/- 2.7%), and both obese groups were significantly lower than the control group (50.0 +/- 2.6%). Insulin-stimulated glucose transport, determined on 28 subjects, was significantly lower in both the obese (3.83 +/- 0.48 nmol.min-1.mg-1) and NIDDM (3.93 +/- 1.0 nmol.min-1.mg-1) groups vs. the control group (7.35 +/- 1.50 nmol.min-1.mg-1). Body mass index (BMI) was inversely correlated to percent type I fibers (r = -0.50, P < 0.01) and to the insulin-stimulated glucose transport rate (r = -0.53, P < 0.01). The percentage of type I muscle fibers was related to the insulin-stimulated glucose transport rate (r = 0.57, P < 0.01), although this relationship was not significant after adjusting for BMI. Although these data do not support an independent relationship between fiber type and insulin action in obesity, a reduced skeletal muscle type I fiber population may be one component of a multifactorial process involved in the development of insulin resistance.

scholarly journals Measurement of force and calcium release using mechanically skinned fibers from mammalian skeletal muscle

2018 ◽  
Vol 125 (4) ◽  
pp. 1105-1127 ◽  
Author(s):  
Graham D. Lamb ◽  
D. George Stephenson
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Calcium Release ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Ec Coupling ◽  
Skeletal Muscle Fibers ◽  
Intact Muscle ◽  
Key Variables ◽  
Coupling Sequence

The mechanically skinned (or “peeled”) skeletal muscle fiber technique is a highly versatile procedure that allows controlled examination of each of the steps in the excitation-contraction (EC)-coupling sequence in skeletal muscle fibers, starting with excitation/depolarization of the transverse tubular (T)-system through to Ca2+ release from sarcoplasmic reticulum (SR) and finally force development by the contractile apparatus. It can also show the overall response of the whole EC-coupling sequence together, such as in twitch and tetanic force responses. A major advantage over intact muscle fiber preparations is that it is possible to set and rapidly manipulate the “intracellular” conditions, allowing examination of the effects of key variables (e.g., intracellular pH, ATP levels, redox state, etc.) on each individual step in EC coupling. This Cores of Reproducibility in Physiology (CORP) article describes the rationale, procedures, and experimental details of the various ways in which the mechanically skinned fiber technique is used in our laboratory to examine the physiological mechanisms controlling Ca2+ release and contraction in skeletal muscle fibers and the aberrations and dysfunction occurring with exercise and disease.

scholarly journals Hypoxia Preconditioned Mesenchymal Stem Cells Improve Vascular and Skeletal Muscle Fiber Regeneration After Ischemia Through a Wnt4-dependent Pathway

2010 ◽  
Vol 18 (8) ◽  
pp. 1545-1552 ◽  
Author(s):  
Lionel Leroux ◽  
Betty Descamps ◽  
Nancy F Tojais ◽  
Benjamin Séguy ◽  
Pierre Oses ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Muscle Fiber ◽  
Skeletal Muscle Fiber ◽  
Dependent Pathway ◽  
Muscle Fiber Regeneration

Contractile properties of bundles of fiber segments from skeletal muscles

1982 ◽  
Vol 243 (1) ◽  
pp. C66-C73 ◽  
Author(s):  
J. A. Faulkner ◽  
D. R. Claflin ◽  
K. K. McCully ◽  
D. A. Jones
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Skeletal Muscles ◽  
Maximum Velocity ◽  
Skeletal Muscle Fiber ◽  
Contractile Properties ◽  
Tension Development ◽  
Velocity Of Shortening ◽  
Lower Maximum ◽  
Fixed End

Our purpose was to determine whether contractile properties of bundles of skeletal muscle fiber segments were significantly different from those of bundles of intact fibers. In frog muscles, the only difference between the contractile properties of fiber segments and intact fibers was a lower maximum velocity of shortening (Vo) for the fiber segments. In mammalian muscles, the contraction time (TPT), relaxation time (RT1/2), and maximum tetanus tension (Po) of bundles of fiber segments were not different from those of intact fibers, but the rate of tension development (dP/dt), twitch-to-tetanus ratio (Pt/Po) and Vo were lower. The lower dP/dt and Pt/Po resulted from increased compliance due to damaged sarcomeres near cut ends. Within 4-9 mm of a cut end, membrane potentials were less than control values, and sarcomeres lengthened during a fixed-end contraction. after the length of fiber segments was corrected for the exact portion that was not shortening, the Vo of fiber segments was not different from that of intact fibers. We conclude that valid estimates of contractile properties can be obtained from bundles of skeletal muscle fiber segments.

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