scholarly journals Skeletal muscle adaptations to microgravity exposure in the mouse

2003 ◽  
Vol 95 (6) ◽  
pp. 2462-2470 ◽  
Author(s):  
B. C. Harrison ◽  
D. L. Allen ◽  
B. Girten ◽  
L. S. Stodieck ◽  
P. J. Kostenuik ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Citrate Synthase ◽  
Space Shuttle ◽  
Immunohistochemical Analysis ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Isoform Expression

To investigate the effects of microgravity on murine skeletal muscle fiber size, muscle contractile protein, and enzymatic activity, female C57BL/6J mice, aged 64 days, were divided into animal enclosure module (AEM) ground control and spaceflight (SF) treatment groups. SF animals were flown on the space shuttle Endeavour (STS-108/UF-1) and subjected to ∼11 days and 19 h of microgravity. Immunohistochemical analysis of muscle fiber cross-sectional area revealed that, in each of the muscles analyzed, mean muscle fiber cross-sectional area was significantly reduced ( P < 0.0001) for all fiber types for SF vs. AEM control. In the soleus, immunohistochemical analysis of myosin heavy chain (MHC) isoform expression revealed a significant increase in the percentage of muscle fibers expressing MHC IIx and MHC IIb ( P < 0.05). For the gastrocnemius and plantaris, no significant changes in MHC isoform expression were observed. For the muscles analyzed, no alterations in MHC I or MHC IIa protein expression were observed. Enzymatic analysis of the gastrocnemius revealed a significant decrease in citrate synthase activity in SF vs. AEM control.

scholarly journals Exposure to cigarette smoke induces overexpression of von Hippel-Lindau tumor suppressor in mouse skeletal muscle

2012 ◽  
Vol 303 (6) ◽  
pp. L519-L527 ◽  
Author(s):  
Vladimir T. Basic ◽  
Elsa Tadele ◽  
Ali Ateia Elmabsout ◽  
Hongwei Yao ◽  
Irfan Rahman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tumor Suppressor ◽  
Cigarette Smoke ◽  
Muscle Fiber ◽  
Exercise Tolerance ◽  
Skeletal Muscles ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Von Hippel Lindau

Cigarette smoke (CS) is a well-established risk factor in the development of chronic obstructive pulmonary disease (COPD). In contrast, the extent to which CS exposure contributes to the development of the systemic manifestations of COPD, such as skeletal muscle dysfunction and wasting, remains largely unknown. Decreased skeletal muscle capillarization has been previously reported in early stages of COPD and might play an important role in the development of COPD-associated skeletal muscle abnormalities. To investigate the effects of chronic CS exposure on skeletal muscle capillarization and exercise tolerance, a mouse model of CS exposure was used. The 129/SvJ mice were exposed to CS for 6 mo, and the expression of putative elements of the hypoxia-angiogenic signaling cascade as well as muscle capillarization were studied. Additionally, functional tests assessing exercise tolerance/endurance were performed in mice. Compared with controls, skeletal muscles from CS-exposed mice exhibited significantly enhanced expression of von Hippel-Lindau tumor suppressor (VHL), ubiquitin-conjugating enzyme E2D1 (UBE2D1), and prolyl hydroxylase-2 (PHD2). In contrast, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression was reduced. Furthermore, reduced muscle fiber cross-sectional area, decreased skeletal muscle capillarization, and reduced exercise tolerance were also observed in CS-exposed animals. Taken together, the current results provide evidence linking chronic CS exposure and induction of VHL expression in skeletal muscles leading toward impaired hypoxia-angiogenesis signal transduction, reduced muscle fiber cross-sectional area, and decreased exercise tolerance.

Microcirculatory structure-function relationships in skeletal muscle of diabetic rats

1994 ◽  
Vol 266 (4) ◽  
pp. H1502-H1511 ◽  
Author(s):  
W. L. Sexton ◽  
D. C. Poole ◽  
O. Mathieu-Costello
Keyword(s):  
Skeletal Muscle ◽  
Structure Function ◽  
Surface Area ◽  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Diffusing Capacity ◽  
Capillary Surface ◽  
Cross Sectional

The effects of streptozotocin-induced diabetes on microcirculatory structure-function relationships in skeletal muscle were studied in control (C) and diabetic (D; 65 mg/kg streptozotocin ip) rats 6-8 wk after injection. Capillary exchange capacity was determined from measurements of capillary filtration coefficient (CFC) and permeability-surface area product (PS) for 51Cr-labeled EDTA in maximally vasodilated (papaverine), isolated hindquarters of C (n = 9) and D (n = 12) rats. Capillary numerical density, length, surface area, capillary geometry, and muscle fiber cross-sectional area were determined using morphometric methods in perfusion-fixed plantaris muscles from a second series of C (n = 5) and D (n = 6) rats. Hindquarters of D rats (61 +/- 3 g) weighed less than C rats (90 +/- 3 g) because of marked muscle atrophy. Minimal total vascular resistance was lower in D rats (P < or = 0.05), indicating an increased flow capacity. CFC was not different in C and D rats (0.0282 +/- 0.0020 vs. 0.0330 +/- 0.0025 ml.min-1.mmHg-1 x 100 g-1, respectively). The relationship between PS and flow was depressed in D rats (P < or = 0.05) compared with C rats, which indicated a reduced capillary diffusing capacity. Plantaris muscle weight was 41% less in D rats (174 +/- 9 vs. 293 +/- 11 mg; P < or = 0.001). Morphometric analysis revealed that muscle fiber cross-sectional area was reduced 39% in D rats, which, despite a lower capillary-to-fiber ratio (1.59 +/- 0.04 vs. 2.12 +/- 0.13; P < or = 0.001), resulted in a 27% increase in capillary density in D rats. Capillary diameter was less in D rats (3.58 +/- 0.12 vs. 4.51 +/- 0.23 microns; P < or = 0.005). Total capillary surface area was reduced 42% in D rats; however, capillary surface area per muscle fiber volume was unchanged in D rats (231 +/- 34 vs. 237 +/- 16 cm-1). These data indicate that there is remodeling of the capillary bed in skeletal muscle of D rats, resulting in a reduction in total microvascular surface area. The reduction in capillary surface area is proportional to the degree of muscle atrophy in D rats such that functional microvascular surface area per tissue mass (e.g., CFC) is unchanged. The lower diffusing capacity (PS) in D rats suggests that either small solute permeability is reduced and/or there is greater perfusion heterogeneity in D rat skeletal muscle.

scholarly journals Automated fiber-type-specific cross-sectional area assessment and myonuclei counting in skeletal muscle

2013 ◽  
Vol 115 (11) ◽  
pp. 1714-1724 ◽  
Author(s):  
Fujun Liu ◽  
Christopher S. Fry ◽  
Jyothi Mula ◽  
Janna R. Jackson ◽  
Jonah D. Lee ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Automated Image Analysis ◽  
Muscle Fiber Type ◽  
Sectional Area ◽  
Cross Sectional ◽  
Exercise Interventions ◽  
Structural And Functional Properties

Skeletal muscle is an exceptionally adaptive tissue that compromises 40% of mammalian body mass. Skeletal muscle functions in locomotion, but also plays important roles in thermogenesis and metabolic homeostasis. Thus characterizing the structural and functional properties of skeletal muscle is important in many facets of biomedical research, ranging from myopathies to rehabilitation sciences to exercise interventions aimed at improving quality of life in the face of chronic disease and aging. In this paper, we focus on automated quantification of three important morphological features of muscle: 1) muscle fiber-type composition; 2) muscle fiber-type-specific cross-sectional area, and 3) myonuclear content and location. We experimentally prove that the proposed automated image analysis approaches for fiber-type-specific assessments and automated myonuclei counting are fast, accurate, and reliable.

Effect of nutritional deprivation on diaphragm contractility and muscle fiber size

1986 ◽  
Vol 60 (2) ◽  
pp. 596-603 ◽  
Author(s):  
M. I. Lewis ◽  
G. C. Sieck ◽  
M. Fournier ◽  
M. J. Belman
Keyword(s):  
Muscle Fiber ◽  
Daily Intake ◽  
Cross Sectional Area ◽  
The Body ◽  
Fatigue Properties ◽  
Fiber Types ◽  
Force Frequency ◽  
Sectional Area ◽  
Cross Sectional ◽  
Nutritional Deprivation

The influence of nutritional deprivation on the contractile and fatigue properties of the diaphragm was studied in adult rats. Food access was restricted to one-third of normal daily intake until the body weight of nutritionally deprived (ND) animals was approximately 50% of controls (CTL). Isometric contractile properties were studied in an in vitro nerve muscle strip preparation. Both twitch (Pt) and tetanic (Po) tensions of diaphragms from the ND animals were markedly reduced compared with CTL; however, Pt/Po was higher for the ND group. The shape of the force-frequency curve (normalized to Po) was generally similar between the two groups, except at 5 and 10 pulses/s stimulation, where greater relative tensions were produced in diaphragms from the ND animals. Diaphragm fatigue was induced by repetitive stimulation at either 20 or 100 pulses/s. Endurance time (defined as the time required for tension to fall to 50% of initial) of diaphragms from ND animals was prolonged at both 20 and 100 pulses/s. Immediately after induction of fatigue, force-frequency curves for both ND and CTL diaphragms were shifted to the right. However, this rightward shift was attenuated in the ND group compared with CTL. Nutritional deprivation had no effect on the proportions of different fiber types within the diaphragm but did result in a significant decrease in the cross-sectional area of both fast-and slow-twitch fibers. This decrease in cross-sectional area was significantly greater for fast-twitch fibers. We conclude that these changes in diaphragm contractile and fatigue properties occur as a result of the influence of malnutrition on muscle fiber cross-sectional area.

Changes in satellite cell mitotic activity during acute period of unilateral diaphragm denervation

1994 ◽  
Vol 77 (3) ◽  
pp. 1128-1134 ◽  
Author(s):  
L. E. Gosselin ◽  
G. Brice ◽  
B. Carlson ◽  
Y. S. Prakash ◽  
G. C. Sieck
Keyword(s):  
Mitotic Activity ◽  
Satellite Cell ◽  
Muscle Fiber ◽  
Muscle Injury ◽  
Cross Sectional Area ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Acute Period

The acute period of unilateral diaphragm denervation (DNV) is associated with increases in cell mitotic activity, protein synthesis, and muscle fiber hypertrophy. Our purpose was to determine whether acute unilateral diaphragm DNV is associated with changes in muscle isometric contractile properties, cross-sectional area of different muscle fiber types, mitotic activity of muscle fiber satellite cells, and muscle fiber ultrastructural properties indicative of injury. Adult male Fischer 344 rats underwent a right phrenicotomy, and DNV and intact (INT) hemidiaphragms were studied 72 h later. DNV hemidiaphragm displayed a significant decline in maximal isometric force (8.7 vs. 24.3 N/cm2) and a prolonged time to peak twitch force (47.8 vs. 37.5 ms) and time to half relaxation (72.3 vs. 44.3 ms) compared with INT contralateral hemidiaphragm (P < 0.05). DNV resulted in a significant increase in cross-sectional area of types I (33%), IIa (35%), and IIb (28%) fibers relative to INT hemidiaphragm (P < 0.05). Satellite cell mitotic activity (assessed by incorporation of bromodeoxyuridine) was approximately 5.5 times greater in DNV than in INT muscle (DNV 25.0 +/- 3.8, INT 4.5 +/- 1.4 labeled satellite cell nuclei/1,000 nuclei; P < 0.05). Ultrastructural examination of electron micrographs revealed alterations in Z-line and sarcomeric structure indicative of muscle injury. Cellular infiltration and segmental necrosis were also noted in some fibers. We conclude that acute unilateral diaphragm DNV results in muscle fiber injury that induces satellite cell activation. We also speculate that the specific force decrement associated with DNV is at least partially the result of muscle injury.

scholarly journals An evaluation of the reliability of muscle fiber cross-sectional area and fiber number measurements in rat skeletal muscle

2013 ◽  
Vol 15 (1) ◽  
Author(s):  
Lisa Ceglia ◽  
Sathit Niramitmahapanya ◽  
Lori L Price ◽  
Susan S Harris ◽  
Roger A Fielding ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Rat Skeletal Muscle ◽  
Cross Sectional ◽  
Fiber Number

scholarly journals Skeletal muscle atrophy and dysfunction in breast cancer patients: role for chemotherapy-derived oxidant stress

2018 ◽  
Vol 315 (5) ◽  
pp. C744-C756 ◽  
Author(s):  
Blas A. Guigni ◽  
Damien M. Callahan ◽  
Timothy W. Tourville ◽  
Mark S. Miller ◽  
Brad Fiske ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Skeletal Muscle ◽  
Cancer Patients ◽  
Muscle Fiber ◽  
Cross Sectional Area ◽  
Ros Production ◽  
Sectional Area ◽  
Breast Cancer Patients ◽  
Mitochondrial Content ◽  
Cross Sectional

How breast cancer and its treatments affect skeletal muscle is not well defined. To address this question, we assessed skeletal muscle structure and protein expression in 13 women who were diagnosed with breast cancer and receiving adjuvant chemotherapy following tumor resection and 12 nondiseased controls. Breast cancer patients showed reduced single-muscle fiber cross-sectional area and fractional content of subsarcolemmal and intermyofibrillar mitochondria. Drugs commonly used in breast cancer patients (doxorubicin and paclitaxel) caused reductions in myosin expression, mitochondrial loss, and increased reactive oxygen species (ROS) production in C2C12 murine myotube cell cultures, supporting a role for chemotherapeutics in the atrophic and mitochondrial phenotypes. Additionally, concurrent treatment of myotubes with the mitochondrial-targeted antioxidant MitoQ prevented chemotherapy-induced myosin depletion, mitochondrial loss, and ROS production. In patients, reduced mitochondrial content and size and increased expression and oxidation of peroxiredoxin 3, a mitochondrial peroxidase, were associated with reduced muscle fiber cross-sectional area. Our results suggest that chemotherapeutics may adversely affect skeletal muscle in patients and that these effects may be driven through effects of these drugs on mitochondrial content and/or ROS production.

scholarly journals Automated analysis of skeletal muscle fiber cross‐sectional area using CyteSeer image analysis program

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Tatiana Y Kostrominova ◽  
Randall Ingermanson ◽  
Casey A Laris ◽  
Patricia Loy ◽  
Patrick M McDonough
Keyword(s):  
Skeletal Muscle ◽  
Image Analysis ◽  
Muscle Fiber ◽  
Automated Analysis ◽  
Skeletal Muscle Fiber ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Analysis Program ◽  
Cross Sectional

Effects of periodic weight support on medial gastrocnemius fibers of suspended rat

1989 ◽  
Vol 67 (3) ◽  
pp. 945-953 ◽  
Author(s):  
S. C. Graham ◽  
R. R. Roy ◽  
E. O. Hauschka ◽  
V. R. Edgerton
Keyword(s):  
Muscle Fiber ◽  
Enzyme Activities ◽  
Motor Units ◽  
Cross Sectional Area ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Weight Support ◽  
The Mean

Based on the current view that muscle fiber types reflect, at least to some degree, the probability of excitation of motor units in most normal movements, it was hypothesized that brief moderate periods of weight support would have little effect on a muscle that consists predominantly of high-threshold motor units. To test this hypothesis, the effects of 7 days of hindlimb suspension (HS) and HS plus intermittent weight support activity on the size and metabolic properties of individual fibers in the medial gastrocnemius (MG) were studied. HS resulted in a 40% decrease in the mean cross-sectional area of fibers that stain either dark or light for myosin adenosinetriphosphatase (ATPase) at an alkaline preincubation and are located in the deep region (i.e., close to the bone) of the MG. Dark ATPase fibers located in the superficial region were 17% smaller than controls (P greater than 0.05). Although the mean succinate and alpha-glycerophosphate dehydrogenase activities (optical density/min) per muscle fiber were not significantly (P greater than 0.05) affected by HS, it appeared that selected fibers of the deep MG region of HS rats had elevated enzyme activities. HS plus walking on a treadmill for 10 min every 6 h at 5 m/min and at a 19 degrees incline (total of 40 min/day) resulted in mean fiber cross-sectional area and enzyme activities nearer to control than the HS values. All adaptations were much less obvious in the fibers in a superficial (i.e., away from the bone) MG region.(ABSTRACT TRUNCATED AT 250 WORDS)

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