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.

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.

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 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.

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 Automated image analysis of skeletal muscle fiber cross-sectional area

2013 ◽  
Vol 114 (1) ◽  
pp. 148-155 ◽  
Author(s):  
Jyothi Mula ◽  
Jonah D. Lee ◽  
Fujun Liu ◽  
Lin Yang ◽  
Charlotte A. Peterson
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Morphological Characteristics ◽  
Cross Sectional Area ◽  
Segmentation Algorithm ◽  
Automated Image Analysis ◽  
Sectional Area ◽  
Cross Sectional ◽  
Ridge Detection ◽  
Fiber Size

Morphological characteristics of muscle fibers, such as fiber size, are critical factors that determine the health and function of the muscle. However, at this time, quantification of muscle fiber cross-sectional area is still a manual or, at best, a semiautomated process. This process is labor intensive, time consuming, and prone to errors, leading to high interobserver variability. We have developed and validated an automatic image segmentation algorithm and compared it directly with commercially available semiautomatic software currently considered state of the art. The proposed automatic segmentation algorithm was evaluated against a semiautomatic method with manual annotation using 35 randomly selected cross-sectional muscle histochemical images. The proposed algorithm begins with ridge detection to enhance the muscle fiber boundaries, followed by robust seed detection based on concave area identification to find initial seeds for muscle fibers. The final muscle fiber boundaries are automatically delineated using a gradient vector flow deformable model. Our automatic approach is accurate and represents a significant advancement in efficiency; quantification of fiber area in muscle cross sections was reduced from 25–40 min/image to 15 s/image, while accommodating common quantification obstacles including morphological variation (e.g., heterogeneity in fiber size and fibrosis) and technical artifacts (e.g., processing defects and poor staining quality). Automatic quantification of muscle fiber cross-sectional area using the proposed method is a powerful tool that will increase sensitivity, objectivity, and efficiency in measuring muscle adaptation.

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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