scholarly journals Matrix Metalloproteinase-9 Deficiency Results in Decreased Fiber Cross-Sectional Area and Alters Fiber Type Distribution in Mouse Hindlimb Skeletal Muscle

2011 ◽  
Vol 194 (6) ◽  
pp. 510-520 ◽  
Author(s):  
Ryan S. Mehan ◽  
Bradley J. Greybeck ◽  
Kayla Emmons ◽  
William C. Byrnes ◽  
David L. Allen
Keyword(s):  
Skeletal Muscle ◽  
Matrix Metalloproteinase ◽  
Fiber Type ◽  
Matrix Metalloproteinase 9 ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Distribution ◽  
Fiber Type Distribution ◽  
Metalloproteinase 9

scholarly journals MyoSight—semi-automated image analysis of skeletal muscle cross sections

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lyle W. Babcock ◽  
Amy D. Hanna ◽  
Nadia H. Agha ◽  
Susan L. Hamilton
Keyword(s):  
Skeletal Muscle ◽  
Image Analysis ◽  
Cross Sections ◽  
Fiber Type ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Distribution ◽  
Central Nuclei ◽  
Fiber Size ◽  
Fiber Type Distribution

Abstract Background Manual analysis of cross-sectional area, fiber-type distribution, and total and centralized nuclei in skeletal muscle cross sections is tedious and time consuming, necessitating an accurate, automated method of analysis. While several excellent programs are available, our analyses of skeletal muscle disease models suggest the need for additional features and flexibility to adequately describe disease pathology. We introduce a new semi-automated analysis program, MyoSight, which is designed to facilitate image analysis of skeletal muscle cross sections and provide additional flexibility in the analyses. Results We describe staining and imaging methods that generate high-quality images of immunofluorescent-labelled cross sections from mouse skeletal muscle. Using these methods, we can analyze up to 5 different fluorophores in a single image, allowing simultaneous analyses of perinuclei, central nuclei, fiber size, and fiber-type distribution. MyoSight displays high reproducibility among users, and the data generated are in close agreement with data obtained from manual analyses of cross-sectional area (CSA), fiber number, fiber-type distribution, and number and localization of myonuclei. Furthermore, MyoSight clearly delineates changes in these parameters in muscle sections from a mouse model of Duchenne muscular dystrophy (mdx). Conclusions MyoSight is a new program based on an algorithm that can be optimized by the user to obtain highly accurate fiber size, fiber-type identification, and perinuclei and central nuclei per fiber measurements. MyoSight combines features available separately in other programs, is user friendly, and provides visual outputs that allow the user to confirm the accuracy of the analyses and correct any inaccuracies. We present MyoSight as a new program to facilitate the analyses of fiber type and CSA changes arising from injury, disease, exercise, and therapeutic interventions.

Variability in skeletal muscle fibre characteristics during repeated muscle biopsy sampling in human vastus lateralis

2020 ◽  
Vol 45 (4) ◽  
pp. 368-375 ◽  
Author(s):  
Joshua P. Nederveen ◽  
George Ibrahim ◽  
Stephen A. Fortino ◽  
Tim Snijders ◽  
Dinesh Kumbhare ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Biopsy ◽  
Fibre Type ◽  
Vastus Lateralis ◽  
Cross Sectional Area ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Distribution ◽  
Fibre Type Distribution

The percutaneous muscle biopsy procedure is an invaluable tool for characterizing skeletal muscle and capillarization. Little is known about methodological or biological variation stemming from the technique in heterogeneous muscle. Five muscle biopsies were taken from the vastus lateralis of a group of young men (n = 29, 22 ± 1 years) over a 96-h period. We investigated the repeatability of fibre distribution, indices of muscle capillarization and perfusion, and myofibre characteristics. No differences between the biopsies were reported in myofibre type distribution, cross-sectional area (CSA), and perimeter. Capillary-to-fibre perimeter exchange index and individual capillary-fibre contacts were unchanged with respect to the location of the muscle biopsy and index of capillarization. The variability in the sampling distribution of fibre type specific muscle CSA increased when fewer than 150 muscle fibres were quantified. Variability in fibre type distribution increased when fewer than 150 muscle fibres were quantified. Myofibre characteristics and indices of capillarization are largely consistent throughout the vastus lateralis when assessed via the skeletal muscle biopsy technique. Novelty Markers of muscle capillarization and perfusion were unchanged across multiple sites of the human vastus lateralis. Myofibre characteristics such as muscle cross-sectional area, perimeter, and fibre type distribution were also unchanged. Variation of muscle CSA was higher when fewer than 150 muscle fibres were quantified.

The Effects of Non-Weight Bearing on Skeletal Muscle in Older Rats: an Interrupted Bout versus an Uninterrupted Bout

2004 ◽  
Vol 5 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Alissa Guildner Gehrke ◽  
Margaret Sheie Krull ◽  
Robin Shotwell McDonald ◽  
Tracy Sparby ◽  
Jessica Thoele ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Weight Bearing ◽  
Cross Sectional Area ◽  
Type I ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional ◽  
Age Related ◽  
Type Ii Fibers

Age-related changes in skeletal muscle, in combination with bed rest, may result in a poorer rehabilitation potential for an elderly patient. The purpose of this study was to determine the effects of non-weight bearing (hind limb unweighting [HU]) on the soleus and extensor digitorum longus (EDL) in older rats. Two non-weight bearing conditions were used: an uninterrupted bout of HU and an interrupted bout of HU. Twenty-one rats were randomly placed into 1 of 3 groups: control, interrupted HU (2 phases of 7 days of HU, separated by a 4-day weight-bearing phase) and an uninterrupted HU (18 uninterrupted days of HU). Following non-weight bearing, the soleus and EDL muscles were removed. Fiber type identification was performed by myofibrillar ATPase and cross-sectional area was determined. The findings suggest that any period of non-weight bearing leads to a decrease in muscle wet weight (19%-45%). Both type I and type II fibers of the soleus showed atrophy (decrease in cross-sectional area, 35%-44%) with an uninterrupted bout of non-weight bearing. Only the type II fibers of the soleus showed recovery with an interrupted bout of weight bearing. In the EDL, type II fibers were more affected by an uninterrupted bout of non-weight bearing (15% decrease in fiber size) compared to the type I fibers. EDL type II fibers showed more atrophy with interrupted bouts of non-weight bearing than with a single bout (a 40% compared to a 15% decrease). This study shows that initial weight bearing after an episode of non-weight bearing may be damaging to type II fibers of the EDL.

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.

Atrophy, but not necrosis, in rabbit skeletal muscle denervated for periods up to one year

2007 ◽  
Vol 292 (1) ◽  
pp. C440-C451 ◽  
Author(s):  
Z. Ashley ◽  
H. Sutherland ◽  
H. Lanmüller ◽  
M. F. Russold ◽  
E. Unger ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Morphological Changes ◽  
Fiber Type ◽  
Common Peroneal Nerve ◽  
Cross Sectional Area ◽  
Extensive Literature ◽  
Sectional Area ◽  
Cross Sectional ◽  
Muscle Groups

Our understanding of the effects of long-term denervation on skeletal muscle is heavily influenced by an extensive literature based on the rat. We have studied physiological and morphological changes in an alternative model, the rabbit. In adult rabbits, tibialis anterior muscles were denervated unilaterally by selective section of motor branches of the common peroneal nerve and examined after 10, 36, or 51 wk. Denervation reduced muscle mass and cross-sectional area by 50–60% and tetanic force by 75%, with no apparent reduction in specific force (force per cross-sectional area of muscle fibers). The loss of mass was associated with atrophy of fast fibers and an increase in fibrous and adipose connective tissue; the diameter of slow fibers was preserved. Within fibers, electron microscopy revealed signs of ultrastructural disorganization of sarcomeres and tubular systems. This, rather than the observed transformation of fiber type from IIx to IIa, was probably responsible for the slow contractile speed of the muscles. The muscle groups denervated for 10, 36, or 51 wk showed no significant differences. At no stage was there any evidence of necrosis or regeneration, and the total number of fibers remained constant. These changes are in marked contrast to the necrotic degeneration and progressive decline in mass and force that have previously been found in long-term denervated rat muscles. The rabbit may be a better choice for a model of the effects of denervation in humans, at least up to 1 yr after lesion.

scholarly journals Administration of a soluble activin type IIB receptor promotes skeletal muscle growth independent of fiber type

2010 ◽  
Vol 109 (3) ◽  
pp. 635-642 ◽  
Author(s):  
Samuel M. Cadena ◽  
Kathleen N. Tomkinson ◽  
Travis E. Monnell ◽  
Matthew S. Spaits ◽  
Ravindra Kumar ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Musculoskeletal Diseases ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Soluble Form ◽  
Control Group ◽  
Type I ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional

This is the first report that inhibition of negative regulators of skeletal muscle by a soluble form of activin type IIB receptor (ACE-031) increases muscle mass independent of fiber-type expression. This finding is distinct from the effects of selective pharmacological inhibition of myostatin (GDF-8), which predominantly targets type II fibers. In our study 8-wk-old C57BL/6 mice were treated with ACE-031 or vehicle control for 28 days. By the end of treatment, mean body weight of the ACE-031 group was 16% greater than that of the control group, and wet weights of soleus, plantaris, gastrocnemius, and extensor digitorum longus muscles increased by 33, 44, 46 and 26%, respectively ( P < 0.05). Soleus fiber-type distribution was unchanged with ACE-031 administration, and mean fiber cross-sectional area increased by 22 and 28% ( P < 0.05) in type I and II fibers, respectively. In the plantaris, a predominantly type II fiber muscle, mean fiber cross-sectional area increased by 57% with ACE-031 treatment. Analysis of myosin heavy chain (MHC) isoform transcripts by real-time PCR indicated no change in transcript levels in the soleus, but a decline in MHC I and IIa in the plantaris. In contrast, electrophoretic separation of total soleus and plantaris protein indicated that there was no change in the proportion of MHC isoforms in either muscle. Thus these data provide optimism that ACE-031 may be a viable therapeutic in the treatment of musculoskeletal diseases. Future studies should be undertaken to confirm that the observed effects are not age dependent or due to the relatively short study duration.

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