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.

scholarly journals Skeletal muscle fiber size and fiber type distribution in human cancer: Effects of weight loss and relationship to physical function

2016 ◽  
Vol 35 (6) ◽  
pp. 1359-1365 ◽  
Author(s):  
Michael J. Toth ◽  
Damien M. Callahan ◽  
Mark S. Miller ◽  
Timothy W. Tourville ◽  
Sarah B. Hackett ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Weight Loss ◽  
Physical Function ◽  
Muscle Fiber ◽  
Human Cancer ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Type Distribution ◽  
Fiber Size ◽  
Fiber Type Distribution

Fatty acid profile of skeletal muscle phospholipids in trained and untrained young men

2000 ◽  
Vol 279 (4) ◽  
pp. E744-E751 ◽  
Author(s):  
Agneta Andersson ◽  
Anders Sjödin ◽  
Anu Hedman ◽  
Roger Olsson ◽  
Bengt Vessby
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Fatty Acid Profile ◽  
Acid Composition ◽  
Fiber Type ◽  
Young Men ◽  
Trained Group ◽  
Type Distribution ◽  
Fiber Type Distribution

Endurance trained ( n = 14) and untrained young men ( n = 15) were compared regarding the fatty acid profile of the vastus lateralis muscle after 8 wk on diets with a similar fatty acid composition. The skeletal muscle phospholipids in the trained group contained lower proportions of palmitic acid (16:0) (−12.4%, P < 0.001) and di-homo-γ-linolenic acid [20:3(n-6)] (−15.3%, P = 0.018), a lower n-6-to-n-3 ratio (−42.0%, P = 0.015), higher proportions of stearic acid (18:0) (+9.8%, P = 0.004) and sum of n-3 polyunsaturated fatty acids (+33.8%, P = 0.009), and a higher ratio between 20:4(n-6) to 20:3(n-6) (+18.4%, P = 0.006) compared with those in the untrained group. The group differences in 16:0, 20:3(n-6), 18:0/16:0, and 20:4(n-6)/20:3(n-6) were independent of fiber-type distribution. The trained group also showed a lower proportion of 16:0 (−7.9%, P < 0.001) in skeletal muscle triglycerides irrespective of fiber type. In conclusion, the fatty acid profile of the skeletal muscle differed between trained and untrained individuals, although the dietary fatty acid composition was similar. This difference was not explained by different fiber-type distribution alone but appears to be a direct consequence of changes in fatty acid metabolism due to the higher level of physical activity.

Changes in skeletal muscle in males and females following endurance training

2001 ◽  
Vol 79 (5) ◽  
pp. 386-392 ◽  
Author(s):  
S L Carter ◽  
C D Rennie ◽  
S J Hamilton ◽  
M A Tarnopolsky
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Endurance Exercise ◽  
Fiber Type ◽  
Oxidative Potential ◽  
Muscle Enzyme ◽  
Type Distribution ◽  
Endurance Exercise Training ◽  
Fiber Type Distribution ◽  
Males And Females

Gender differences in substrate selection have been reported during endurance exercise. To date, no studies have looked at muscle enzyme adaptations following endurance exercise training in both genders. We investigated the effect of a 7-week endurance exercise training program on the activity of β-oxidation, tricarboxylic acid cycle and electron transport chain enzymes, and fiber type distribution in males and females. Training resulted in an increase in [Formula: see text]O2peak for both males and females of 17% and 22%, respectively (P < 0.001). The following muscle enzyme activities increased similarly in both genders: 3-β-hydroxyacyl CoA dehydrogenase (38%), citrate synthase (41%), succinate-cytochrome c oxidoreductase (41%), and cytochrome c oxidase (COX; 26%). The increase in COX activity was correlated (R2 = 0.52, P < 0.05) with the increase in [Formula: see text]O2peak/ fat free mass. Fiber area, size, and % area were not affected by training for either gender, however, males had larger Type II fibers (P < 0.05) and females had a greater Type I fiber % area (P < 0.05). Endurance training resulted in similar increases in skeletal muscle oxidative potential for both males and females. Training did not affect fiber type distribution or size in either gender.Key words: endurance training, oxidative potential, gender.

Absence of a growth hormone effect on rat soleus atrophy during a 4-day spaceflight

1993 ◽  
Vol 74 (2) ◽  
pp. 527-531 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
C. Navarro ◽  
V. R. Edgerton
Keyword(s):  
Growth Hormone ◽  
Succinate Dehydrogenase ◽  
Cross Sections ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Hormone Effect ◽  
Fast Myosin Heavy Chain

The objectives of the present study were to determine the size and enzyme properties of soleus fibers of rats subjected to a 4-day spaceflight (National Aeronautics and Space Administration, STS-41) and the effects of exogenous growth hormone (GH) on the atrophic response of the muscle. Four groups of rats were studied: 1) control (Con), 2) Con plus GH treated (Con + GH), 3) flight (Fl), and 4) F1 plus GH treated (Fl + GH). Cross-sectional area and the activities of succinate dehydrogenase and myofibrillar adenosinetriphosphatase (ATPase) were determined in fibers identified in frozen serial cross sections. Fibers were categorized immunohistochemically as slow, fast, or slow-fast on the basis of their reaction with slow and fast myosin heavy-chain (MHC) monoclonal antibodies. Fibers also were categorized as light or dark on the basis of their staining for ATPase at pH 8.6. After the 4-day flight, mean body weight was significantly decreased compared with control. The absolute and relative (muscle wt/body wt) soleus weights were significantly smaller in the Fl and Fl + GH rats compared with their respective ground-based controls. In both flight groups, the cross-sectional area of the light ATPase fibers was significantly smaller (approximately 30%) than control. Three of 11 flight rats had a higher proportion of fibers expressing both slow and fast MHCs than expected on the basis of the fiber type distribution in the 11 control rats. Mean fiber succinate dehydrogenase and ATPase activities were similar among the four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Prolonged C2 spinal hemisection-induced inactivity reduces diaphragm muscle specific force with modest, selective atrophy of type IIx and/or IIb fibers

2013 ◽  
Vol 114 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Carlos B. Mantilla ◽  
Sarah M. Greising ◽  
Wen-Zhi Zhan ◽  
Yasin B. Seven ◽  
Gary C. Sieck
Keyword(s):  
Spinal Cord ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Diaphragm Muscle ◽  
Emg Activity ◽  
Type I ◽  
Specific Force ◽  
Type Distribution ◽  
Fiber Size ◽  
Fiber Type Distribution

The diaphragm muscle (DIAm) is critically responsible for sustaining ventilation. Previously we showed in a commonly used model of spinal cord injury, unilateral spinal cord hemisection at C2 (SH), that there are minimal changes to muscle fiber cross-sectional area (CSA) and fiber type distribution following 14 days of SH-induced ipsilateral DIAm inactivity. In the present study, effects of long-term SH-induced inactivity on DIAm fiber size and force were examined. We hypothesized that prolonged inactivity would not result in substantial DIAm atrophy or force loss. Adult rats were randomized to control or SH groups ( n = 34 total). Chronic bilateral DIAm electromyographic (EMG) activity was monitored during resting breathing. Minimal levels of spontaneous recovery of ipsilateral DIAm EMG activity were evident in 42% of SH rats (<25% of preinjury root mean square amplitude). Following 42 days of SH, DIAm specific force was reduced 39%. There was no difference in CSA for type I or IIa DIAm fibers in SH rats compared with age, weight-matched controls (classification based on myosin heavy chain isoform expression). Type IIx and/or IIb DIAm fibers displayed a modest 20% reduction in CSA ( P < 0.05). Overall, there were no differences in the distribution of fiber types or the contribution of each fiber type to the total DIAm CSA. These data indicate that reduced specific force following prolonged inactivity of the DIAm is associated with modest, fiber type selective adaptations in muscle fiber size and fiber type distribution.

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