A semi-automated measurement of muscle fiber size using the Imaris software

2021 ◽  
Author(s):  
Jennifer E. Gilda ◽  
Joon-Hyuk Ko ◽  
Aviv-Yvonne Elfassy ◽  
Nadav Tropp ◽  
Anna Parnis ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Statistical Tests ◽  
Muscle Fibers ◽  
Fluorescent Labeling ◽  
Cross Sectional ◽  
Short Period ◽  
Fiber Size ◽  
Specific Protease

The size and shape of skeletal muscle fibers are affected by various physiological and pathological conditions, such as muscle atrophy, hypertrophy, regeneration, and dystrophies. Hence, muscle fiber cross-sectional area (CSA) is an important determinant of muscle health and plasticity. We adapted the Imaris software to automatically segment muscle fibers based on fluorescent labeling of the plasma membrane, and measure muscle fiber CSA. Analysis of muscle cross sections by the Imaris semi-automated and manual approaches demonstrated a similar decrease in CSA of atrophying muscles from fasted mice compared with fed controls. In addition, we previously demonstrated that downregulation of the Ca2+-specific protease calpain-1 attenuates muscle atrophy. Accordingly, both the Imaris semi-automated and manual approaches showed a similar increase in CSA of fibers expressing calpain-1 shRNA compared with adjacent non-transfected fibers in the same muscle cross section. Although both approaches seem valid for measurements of muscle fiber size, the manual marking method is less preferable because it is highly time-consuming, subjective, and limits the number of cells that can be analyzed. The Imaris semi-automated approach is user-friendly, requires little training or optimization, and can be used to efficiently and accurately mark thousands of fibers in a short period of time. As a novel addition to the commonly used statistics, we also describe statistical tests that quantify the strength of an effect on fiber size, enabling detection of significant differences between skewed distributions that would otherwise not be detected using typical methods.

Exercise-induced focal skeletal muscle fiber degeneration and capillary morphology

1989 ◽  
Vol 66 (6) ◽  
pp. 2857-2865 ◽  
Author(s):  
F. M. Peeze Binkhorst ◽  
H. Kuipers ◽  
J. Heymans ◽  
P. M. Frederik ◽  
D. W. Slaaf ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Fiber ◽  
Cross Sections ◽  
Muscle Fibers ◽  
Basal Membrane ◽  
Cross Sectional ◽  
Male Wistar Rats ◽  
Muscle Water Content ◽  
Exercise Muscle ◽  
Exercise Induced

The relationship between exercise-induced focal muscle fiber degeneration and changes in capillary morphology was investigated in male Wistar rats. Untrained animals ran on a treadmill for 1 h at submaximal intensity and were killed 0, 6, or 24 h after running. Nonexercised rats served as controls. In situ perfused soleus muscles were prepared for electron microscopy. Micrographed cross sections were quantitatively analyzed for parameters indicative of capillary blood flow or transcapillary exchange. Capillary lumina were ovally rather than circularly shaped, and no indications for obstruction of blood flow at the capillary level were found. Endothelial cells and their organelles had a normal appearance in all groups. However, immediately after exercise, capillaries showed a decreased thickness of their endothelium and basal membrane, probably caused by dehydration. Six hours after exercise, muscle fibers were swollen (28% increase in cross-sectional area), resulting in a slightly increased diffusion distance. This fiber swelling was not associated with an increase in muscle water content, a finding for which no explanation could be found. Twenty-four hours after the animals ran, capillaries located near degenerated muscle fibers had an increased cross-sectional luminal area and an increased luminal circumference. This effect decreased gradually with increasing distance from the degenerated fiber area. The present morphometric results do not support the hypothesis that changes in capillary morphology primarily contribute to exercise-induced focal muscle fiber degeneration.

scholarly journals Genomic predictors of testosterone levels are associated with muscle fiber size and strength

2021 ◽  
Author(s):  
João Paulo L. F. Guilherme ◽  
Ekaterina A. Semenova ◽  
Oleg V. Borisov ◽  
Andrey K. Larin ◽  
Ethan Moreland ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Handgrip Strength ◽  
Muscle Fibers ◽  
Fat Free Mass ◽  
Nucleotide Polymorphisms ◽  
Cross Sectional ◽  
Testosterone Levels ◽  
Fiber Size ◽  
Fast Twitch Muscle ◽  
Fast Twitch

Abstract Purpose Circulating testosterone levels are a heritable trait with anabolic properties in various tissues, including skeletal muscle. So far, hundreds of single nucleotide polymorphisms (SNPs) associated with testosterone levels have been identified in nonathletic populations. The aim of the present study was to test the association of 822 testosterone-increasing SNPs with muscle-related traits (muscle fiber size, fat-free mass and handgrip strength) and to validate the identified SNPs in independent cohorts of strength and power athletes. Methods One hundred and forty-eight physically active individuals (47 females, 101 males) were assessed for cross-sectional area (CSA) of fast-twitch muscle fibers. Significant SNPs were further assessed for fat-free mass and handgrip strength in > 354,000 participants from the UK Biobank cohort. The validation cohorts included Russian elite athletes. Results From an initial panel of 822 SNPs, we identified five testosterone-increasing alleles (DOCK3 rs77031559 G, ESR1 rs190930099 G, GLIS3 rs34706136 TG, GRAMD1B rs850294 T, TRAIP rs62260729 C) nominally associated (P < 0.05) with CSA of fast-twitch muscle fibers, fat-free mass and handgrip strength. Based on these five SNPs, the number of testosterone-increasing alleles was positively associated with testosterone levels in male athletes (P = 0.048) and greater strength performance in weightlifters (P = 0.017). Moreover, the proportion of participants with ≥ 2 testosterone-increasing alleles was higher in power athletes compared to controls (68.9 vs. 55.6%; P = 0.012). Conclusion Testosterone-related SNPs are associated with muscle fiber size, fat-free mass and strength, which combined can partially contribute to a greater predisposition to strength/power sports.

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.

Motoneuron and muscle fiber succinate dehydrogenase activity in control and overloaded plantaris

1991 ◽  
Vol 71 (4) ◽  
pp. 1589-1592 ◽  
Author(s):  
G. R. Chalmers ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Succinate Dehydrogenase ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Cell Types ◽  
Mitochondrial Proteins ◽  
Succinate Dehydrogenase Activity ◽  
Fiber Size ◽  
The Right ◽  
Gastrocnemius Muscles ◽  
Selective Increase

To determine the level of coordination in succinate dehydrogenase (SDH) activity between plantaris motoneurons and muscle fibers, the soleus and gastrocnemius muscles were bilaterally excised in four cats to subject the plantaris to functional overload (FO). Five normal cats served as controls. Twelve weeks after surgery the right plantaris in each cat was injected with horseradish peroxidase to identify plantaris motoneurons. SDH activity then was measured in a population of plantaris motoneurons and muscle fibers in each cat. Control motoneurons and muscle fibers had similar mean SDH activities and a similar relationship between cell size and SDH activity. After FO, muscle fiber size doubled and mean muscle fiber SDH activity halved. Motoneuron mean SDH activity and size were unaffected by FO. Total SDH activity was unchanged in both the motoneurons and muscle fibers after FO. These changes suggest a selective increase in contractile proteins with little or no modulation of mitochondrial proteins in the muscle fibers, because total SDH activity was unchanged in muscle fibers after FO. These data demonstrate that although mean SDH activities were similar in control motoneurons and muscle fibers, mean SDH activities in these two cell types can change independently.

scholarly journals Imobilização articular: efeitos sobre o tecido muscular de camundongos obesos e desnutridos

2016 ◽  
Vol 18 (1) ◽  
pp. 1 ◽  
Author(s):  
Renato Rissi ◽  
George Azevedo Lemos ◽  
Bernardo Neme Ide ◽  
Rafael Ludemann Camargo ◽  
Renato Chaves Souto Branco ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Tibialis Anterior ◽  
Muscle Fibers ◽  
Musculoskeletal Injuries ◽  
Control Group ◽  
Adhesive Tape ◽  
Male Mice ◽  
Histomorphometric Analysis ◽  
Short Period ◽  
Malnourished Group

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n1p1 Although it is a widely used resource for the treatment of musculoskeletal injuries, immobilization causes deleterious effects in muscle tissue after a short period of time. This study aimed to evaluate the gastrocnemius and tibialis anterior muscles of obese and protein malnourished animals under joint immobilization condition. Overall, 28 adult male mice were used (C57 / BL6), being divided into four groups (N = 7): Control Group (CG), Immobilized Control Group (ICG), Immobilized Obese Group (IOG) and Immobilized Malnourished Group (IMG). The immobilization protocol was performed by the use of adhesive tape and plaster. The conditions and obesity and protein malnutrition have been developed through the ingestion of diets specific for each group of animals. The histomorphometric analysis of muscles evaluated area and the diameter of muscle fibers. All immobilized groups showed reduction in the area and diameter of muscle fibers when compared to GC. Comparisons among immobilized groups showed that the area and diameter of muscle fibers of IOG and IMG were lower than ICG. The immobilization protocol caused reduction in muscle trophism in animals, and obese and malnourished animals suffered high losses under condition of muscle atrophy. 

scholarly journals β-Cryptoxanthin Improves p62 Accumulation and Muscle Atrophy in the Soleus Muscle of Senescence-Accelerated Mouse-Prone 1 Mice

Nutrients ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2180
Author(s):  
Mari Noguchi ◽  
Tomoya Kitakaze ◽  
Yasuyuki Kobayashi ◽  
Katsuyuki Mukai ◽  
Naoki Harada ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Soleus Muscle ◽  
Muscle Fibers ◽  
Skeletal Muscle Atrophy ◽  
Related Factor ◽  
Related Factors ◽  
Cross Sectional ◽  
Senescence Accelerated Mouse

We investigated the effects of β-cryptoxanthin on skeletal muscle atrophy in senescence-accelerated mouse-prone 1 (SAMP1) mice. For 15 weeks, SAMP1 mice were intragastrically administered vehicle or β-cryptoxanthin. At 35 weeks of age, the skeletal muscle mass in SAMP1 mice was reduced compared with that in control senescence-accelerated mouse-resistant 1 (SAMR1) mice. β-cryptoxanthin increased muscle mass with an increase in the size of muscle fibers in the soleus muscle of SAMP1 mice. The expressions of autophagy-related factors such as beclin-1, p62, LC3-I, and LC3-II were increased in the soleus muscle of SAMP1 mice; however, β-cryptoxanthin administration inhibited this increase. Unlike in SAMR1 mice, p62 was punctately distributed throughout the cytosol in the soleus muscle fibers of SAMP1 mice; however, β-cryptoxanthin inhibited this punctate distribution. The cross-sectional area of p62-positive fiber was smaller than that of p62-negative fiber, and the ratio of p62-positive fibers to p62-negative fibers was increased in SAMP1 mice. β-cryptoxanthin decreased this ratio in SAMP1 mice. Furthermore, β-cryptoxanthin decreased the autophagy-related factor expression in murine C2C12 myotube. The autophagy inhibitor bafilomycin A1, but not the proteasome inhibitor MG132, inhibited the β-cryptoxanthin-induced decrease in p62 and LC3-II expressions. These results indicate that β-cryptoxanthin inhibits the p62 accumulation in fibers and improves muscle atrophy in the soleus muscle of SAMP1 mice.

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.

Degenerative changes in the muscle fibers of Manduca sexta during metamorphosis

1992 ◽  
Vol 167 (1) ◽  
pp. 91-117 ◽  
Author(s):  
M. B. Rheuben
Keyword(s):  
Manduca Sexta ◽  
Basal Lamina ◽  
Muscle Fiber ◽  
Structural Changes ◽  
Muscle Fibers ◽  
Resting Potential ◽  
Ultrastructural Changes ◽  
Intimate Contact ◽  
Cross Sectional ◽  
Dense Granules

The ultrastructural changes associated with the early stages of degeneration of the larval mesothoracic muscle fibers of Manduca sexta were examined during the prepupal period and on the first day after ecdysis. Over this 5 day period, the muscle fibers decrease in cross-sectional area but increase in apparent surface area compared to the dimensions of early fifth-instar fibers. Large numbers of electron-dense granules or droplets are formed and extruded from the muscle cytoplasm into the hemolymph; this process may account for some of the decrease in muscle fiber mass and may represent a developmental mechanism for recycling nutrients. As the fibers shrink, the thick basal lamina is thrown into folds. Phagocytic hemocytes (granulocytes) congregate in clusters over the surface of the degenerating fibers and appear to remove specifically the basal lamina. The timely removal of the thick larval basal lamina may be essential for subsequent fusion of myoblasts to the residual larval myofibers. The contractile elements within the degenerating muscle fibers become disorganized but are not dysfunctional at the end of the first 12 h after the pupal ecdysis. Tracheoles withdraw from intimate contact with each muscle fiber in its clefts and T-tubules and associate in groups adjacent to it. Mitochondria appear to be degenerating. These structural changes are concurrent with a previously observed decline in resting potential and suggest that a significant change in the electrical properties of the muscle fibers should be expected as well.

scholarly journals The effects of aging on biceps brachii muscle fibers: a morphometrical study from biopsies and autopsies

2003 ◽  
Vol 61 (3A) ◽  
pp. 555-560 ◽  
Author(s):  
Ana Cláudia Mattiello-Sverzut ◽  
Leila Chimelli ◽  
Maria Silvia de Assis Moura ◽  
Silvia Teixeira ◽  
José Alberto Mello de Oliveira
Keyword(s):  
Cross Sections ◽  
Biceps Brachii ◽  
Muscle Fibers ◽  
Atpase Reaction ◽  
Fiber Size ◽  
Effects Of Aging ◽  
Sixth Decade ◽  
Morphometrical Study

OBJECTIVES: In order to study the morphology and size of muscle fibers, cross sections of biceps brachii samples from autopsies, up to 9 hours after death, and biopsies of 72 subjects were compared. The subjects aged 13 to 84 years in both sexes. METHODS: The samples obtained from autopsies (n=47) were from subjects with sudden death, or who died after acute disease without evidence of neuromuscular involvement. The biopsies (n=25) were from patients with symptoms suggestive of inflammatory or metabolic myopathy, not confirmed morphologically. The lesser diameter of muscle fibers was measured using the ATPase reaction. RESULTS: Morphological analysis showed that aging changes were present from the sixth decade in autopsies, and consisted of atrophy and/or type-grouping. The statistical models adjusted for females in both autopsies and biopsies were linear straight with no variation in fiber size with increasing age. The models adjusted for males in both groups were quadratic, indicating that age influenced the size of different type fibers. In males type 2 were larger than type 1 fibers, and than fibers in females. CONCLUSIONS: These values might be useful as controls, helping interpretation of changes in fiber size in samples obtained from biopsies and autopsies.

Plasticity of myonuclear number in hypertrophied and atrophied mammalian skeletal muscle fibers

1995 ◽  
Vol 78 (5) ◽  
pp. 1969-1976 ◽  
Author(s):  
D. L. Allen ◽  
S. R. Monke ◽  
R. J. Talmadge ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Mammalian Skeletal Muscle ◽  
Cross Sectional ◽  
Neuromuscular Activation ◽  
Neuromuscular Activity ◽  
Hindlimb Muscles ◽  
Slow Fiber ◽  
Fiber Size ◽  
Adult Cat

Although a mammalian skeletal muscle fiber may contain thousands of myonuclei, the importance of this number or the potential to modulate it in adult muscle has not been clearly demonstrated. Using immunohistochemistry and confocal microscopy, we examined the plasticity of myonuclear number and fiber size in isolated fast and slow fiber segments from adult cat hindlimb muscles in response to chronic alterations in neuromuscular activity and loading. Compared with slow fibers in the soleus of control cats, myonuclear number in presumably transformed fast fibers was 32% lower and fiber size was decreased 73% after elimination of neuromuscular activation for 6 mo by spinal isolation. Slow fibers in the soleus of spinal-isolated cats had smaller cross-sectional areas, whereas myonuclear number was not significantly different than that in the control cats. Myonuclear number in fast plantaris fibers was more than threefold higher and fiber size was 2.8-fold higher after 3 mo of functional overload compared with the plantaris of control cats. Compared with control slow plantaris fibers, myonuclear number and fiber size also increased in overloaded slow plantaris fibers. These results demonstrate that changes in myonuclear number are associated with changes in myosin type and suggest that modulations in the amount of available DNA may be a factor in regulating cytoplasmic volume of muscle fibers in response to chronic changes in neuromuscular activity.

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