scholarly journals Observations on Normal Skeletal Muscle of Mature Dogs: A Cytochemical, Histochemical, and Morphometric Study

1982 ◽  
Vol 19 (6) ◽  
pp. 577-595 ◽  
Author(s):  
K. G. Braund ◽  
J. A. Mcguire ◽  
C. E. Lincoln
Keyword(s):  
Skeletal Muscle ◽  
Size Variation ◽  
Biceps Femoris ◽  
Morphometric Study ◽  
Type I ◽  
Triceps Brachii ◽  
Diameter Range ◽  
Age Related ◽  
Mean Diameter ◽  
Fiber Size

Cytochemical, histochemical, and morphometric features of skeletal muscle were evaluated in 140 specimens from five appendicular muscles of 28 dogs which were free of neuromuscular disease. Dogs ranged from six months to 15 years of age. Evidence of degeneration and regeneration, cell reactions and architectural change was found but with an incidence of less than 1% of the total myofiber population in any muscle. The number of fibers with internal nuclei never exceeded 1%. The only changes that appeared to be age-related were fiber size variation associated with the presence of small angular type IIA fibers in muscles of dogs seven years of age and older. Percentages of type I, type IIA, and type IIC fibers remained relatively constant in the various muscles in the age range examined. Type I fibers predominated in medial head of triceps brachii and superficial digital flexor muscles, whereas type IIA fibers were more numerous in biceps femoris and long head of triceps brachii muscles. An approximately equal ratio was found in gastrocranius muscles. In any given muscle, type IIC fibers represented less than 2% of the fibers. Statistically significant differences were found in values for fiber size between groups of dogs weighing more than (mean diameter range = 40 to 50 μm) and less than (mean diameter range = 30 to 40 μm) 15 kilograms.

The Effects of Aging and Training on Skeletal Muscle

1998 ◽  
Vol 26 (4) ◽  
pp. 598-602 ◽  
Author(s):  
Donald T. Kirkendall ◽  
William E. Garrett
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Muscle Function ◽  
Cellular Level ◽  
Type I ◽  
Loss Of Function ◽  
Skeletal Muscle Function ◽  
Cross Sectional ◽  
Age Related ◽  
General Slowing

Aging results in a gradual loss of muscle function, and there are predictable age-related alterations in skeletal muscle function. The typical adult will lose muscle mass with age; the loss varies according to sex and the level of muscle activity. At the cellular level, muscles loose both cross-sectional area and fiber numbers, with type II muscle fibers being the most affected by aging. Some denervation of fibers may occur. The combination of these factors leads to an increased percentage of type I fibers in older adults. Metabolically, the glycolytic enzymes seem to be little affected by aging, but the aerobic enzymes appear to decline with age. Aged skeletal muscle produces less force and there is a general “slowing” of the mechanical characteristics of muscle. However, neither reduced muscle demand nor the subsequent loss of function is inevitable with aging. These losses can be minimized or even reversed with training. Endurance training can improve the aerobic capacity of muscle, and resistance training can improve central nervous system recruitment of muscle and increase muscle mass. Therefore, physical activity throughout life is encouraged to prevent much of the age-related impact on skeletal muscle.

scholarly journals Properties of skeletal muscle in the teleost Sternopygus macrurus are unaffected by short-term electrical inactivity

2016 ◽  
Vol 48 (9) ◽  
pp. 699-710 ◽  
Author(s):  
Robert Güth ◽  
Alexander Chaidez ◽  
Manoj P. Samanta ◽  
Graciela A. Unguez
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Electrical Activity ◽  
Muscle Fiber ◽  
Model Systems ◽  
Control Fish ◽  
Type I ◽  
Fiber Types ◽  
Spinal Transection ◽  
Fiber Size

Skeletal muscle is distinguished from other tissues on the basis of its shape, biochemistry, and physiological function. Based on mammalian studies, fiber size, fiber types, and gene expression profiles are regulated, in part, by the electrical activity exerted by the nervous system. To address whether similar adaptations to changes in electrical activity in skeletal muscle occur in teleosts, we studied these phenotypic properties of ventral muscle in the electric fish Sternopygus macrurus following 2 and 5 days of electrical inactivation by spinal transection. Our data show that morphological and biochemical properties of skeletal muscle remained largely unchanged after these treatments. Specifically, the distribution of type I and type II muscle fibers and the cross-sectional areas of these fiber types observed in control fish remained unaltered after each spinal transection survival period. This response to electrical inactivation was generally reflected at the transcript level in real-time PCR and RNA-seq data by showing little effect on the transcript levels of genes associated with muscle fiber type differentiation and plasticity, the sarcomere complex, and pathways implicated in the regulation of muscle fiber size. Data from this first study characterizing the acute influence of neural activity on muscle mass and sarcomere gene expression in a teleost are discussed in the context of comparative studies in mammalian model systems and vertebrate species from different lineages.

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 Microbiopsy Sampling for Examining Age-Related Differences in Skeletal Muscle Fiber Morphology and Composition

2022 ◽  
Vol 12 ◽  
Author(s):  
Garrett M. Hester ◽  
Trisha A. VanDusseldorp ◽  
Phuong L. Ha ◽  
Kaveh Kiani ◽  
Alex A. Olmos ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Peak Torque ◽  
Type I ◽  
Type Ii ◽  
Fiber Morphology ◽  
Specific Strength ◽  
Age Related ◽  
Whole Muscle

Introduction: The increasingly popular microbiopsy is an appealing alternative to the more invasive Bergström biopsy given the challenges associated with harvesting skeletal muscle in older populations. Parameters of muscle fiber morphology and composition derived from the microbiopsy have not been compared between young and older adults.Purpose: The purpose of this study was to examine muscle fiber morphology and composition in young (YM) and older (OM) males using the microbiopsy sampling technique. A secondary aim was to determine if specific strength is associated with serum levels of C-terminal agrin fragment [CAF; an indicator of neuromuscular junction (NMJ) degradation].Methods: Thirty healthy, YM (n = 15, age = 20.7 ± 2.2 years) and OM (n = 15, age = 71.6 ± 3.9 years) underwent ultrasound imaging to determine whole-muscle cross-sectional area (CSA) of the vastus lateralis and rectus femoris as well as isometric and isokinetic (60°⋅s–1 and 180°⋅s–1) peak torque testing of the knee extensors. Microbiopsy samples of the vastus lateralis were collected from 13 YM and 11 OM, and immunofluorescence was used to calculate CSA and proportion of type I and type II fibers.Results: Peak torque was lower in OM at all velocities (p ≤ 0.001; d = 1.39–1.86) but only lower at 180°⋅s–1 (p = 0.003; d = 1.23) when normalized to whole-muscle CSA. Whole-muscle CSA was smaller in OM (p = 0.001; d = 1.34), but atrophy was not present at the single fiber level (p > 0.05). Per individual, ∼900 fibers were analyzed, and type I fiber CSA was larger (p = 0.05; d = 0.94) in OM which resulted in a smaller type II/I fiber CSA ratio (p = 0.015; d = 0.95). CAF levels were not sensitive to age (p = 0.159; d = 0.53) nor associated with specific strength or whole-muscle CSA in OM.Conclusion: The microbiopsy appears to be a viable alternative to the Bergström biopsy for histological analyses of skeletal muscle in older adults. NMJ integrity was not influential for age-related differences in specific strength in our healthy, non-sarcopenic older sample.

Variablity in vastus lateralis fiber type distribution, fiber size and myonuclear content along and the between legs

2021 ◽  
Author(s):  
Oscar Horwath ◽  
Helena Envall ◽  
Julia Röja ◽  
Eric Bengt Emanuelsson ◽  
Gema Sanz ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Domain Size ◽  
Type I ◽  
Longitudinal Orientation ◽  
Type Composition ◽  
Fiber Size ◽  
Myonuclear Domain

Human skeletal muscle characteristics such as fiber type composition, fiber size and myonuclear content are widely studied in clinical and sports related contexts. Being aware of the methodological and biological variability of the characteristics is a critical aspect in study design and outcome interpretation, but comprehensive data on the variability of morphological features in human skeletal muscle is currently limited. Accordingly, in the present study, m. vastus lateralis biopsies (10 per subject) from young and healthy individuals, collected in a systematic manner, were analyzed for various characteristics using immunohistochemistry (n=7) and SDS-PAGE (n=25). None of the analyzed parameters; fiber type % (FT%), type I and II CSA (fCSA), percentage fiber type area (fCSA%), myosin heavy chain composition (MyHC%), type IIX content, myonuclear content or myonuclear domain varied in a systematic manner longitudinally along the muscle or between the two legs. The average within subject coefficient of variation for FT%, fCSA, fCSA%, and MyHC% ranged between 13-18%, but was only 5% for fiber specific myonuclear content, which reduced the variability for myonuclear domain size to 11-12%. Pure type IIX fibers and type IIX MyHC were randomly distributed and present in <24% of the analyzed samples, with the average content being 0.1 and 1.1%, respectively. In conclusion, leg or longitudinal orientation does not seem to be an important aspect to consider when investigating human vastus lateralis characteristics. However, single muscle biopsies should preferably not be used when studying fiber type and fiber size related aspects given the notable sample to sample variability.

AGE- AND SEX-ASSOCIATED CHANGES IN CHEMICAL COMPOSITION OF BOVINE TRICEPS BRACHII INTRAMUSCULAR AND EPIMYSIAL CONNECTIVE TISSUE WITH EMPHASIS ON GLYCOSAMINOGLYCANS

1980 ◽  
Vol 60 (3) ◽  
pp. 643-662 ◽  
Author(s):  
T. NAKANO ◽  
J. R. THOMPSON
Keyword(s):  
Skeletal Muscle ◽  
Hyaluronic Acid ◽  
Connective Tissue ◽  
Dermatan Sulfate ◽  
Postnatal Growth ◽  
Triceps Brachii ◽  
Mature Adults ◽  
Age Related ◽  
Bovine Skeletal Muscle ◽  
Age And Sex

Age-related changes were studied in the bovine intramuscular and epimysial connective tissue components from animals ranging in age from fetuses to 8.9 yr and from 1.2 to 8.9 yr, respectively. Intramuscular concentration of nitrogen increased (P < 0.05), while intramuscular concentrations of collagen and glycosaminoglycans (GAG) decreased (P < 0.05) with age until the animals were yearlings. Epimysial concentration of collagen increased and that of GAG decreased (P < 0.05) with age in the postnatal animals. Maturation was associated with decreasing (P < 0.05) amounts of labile collagen, hexosamine, and sialic acid in both tissues and occurred earlier in intramuscular than in epimysial tissue. Epimysial tissue from males contained more (P < 0.05) collagen and less (P < 0.05) labile hexosamine than epimysial tissue from females of a similar age. Hyaluronic acid and dermatan sulfate were the major GAG in bovine skeletal muscle with small amounts of heparan sulfate, chondroitin 4-sulfate, chondroitin 6-sulfate and heparin. Hyaluronic acid:dermatan sulfate weight ratios were greater (P < 0.05) in the intramuscular than in the epimysial tissues. The ratio values were 2.0–2.7 in intramuscular tissues, while in the epimysial tissues, the values were 0.5–0.6 in the yearlings and young adults and 0.9 in the mature adults. In postnatal animals, intramuscular tissues were associated with a smaller (P < 0.05) proportion of chondroitin 6-sulfate in the total GAG than were epimysial tissues. Both hyaluronic acid and dermatan sulfate concentrations decreased (P < 0.05) during fetal and early postnatal growth in the intramuscular tissue, while in the epimysial tissue, dermatan sulfate concentrations gradually decreased (P < 0.05) with age in the postnatal animals. Skeletal muscle maturation was associated with an increased (P < 0.05) stability of connective tissue and a decreased (P < 0.05) amount of total GAG and glycoproteins.

Effect of denervation on primate laryngeal muscles: a morphologic and morphometric study

1986 ◽  
Vol 100 (5) ◽  
pp. 553-560 ◽  
Author(s):  
V. Sahgal ◽  
M. H. Hast
Keyword(s):  
Size Variation ◽  
Morphometric Study ◽  
Type I ◽  
Type Ii ◽  
Laryngeal Muscles ◽  
Fibre Size ◽  
Show Evidence ◽  
Posterior Cricoarytenoid ◽  
Intrinsic Laryngeal Muscles ◽  
Thyroarytenoid Muscle

AbstractPrimate intrinsic laryngeal muscles studied consisted of Type I and Type II fibres. Type II fibres were larger than Type I fibres. The coefficient of variance of these muscles suggested that the fibre-size variation was similar in all of these muscles. Denervation resulted in shrinking of Type II fibres at two weeks in all the muscles, while at four weeks the thyroarytenoid showed an inflammatory reaction and far greater reduction in size than the other muscles. At eight weeks, however, all the muscles were fibrosed. We conclude that laryngeal muscles begin to show evidence of denervation at two weeks and are fibrosed in eight weeks. The thyroarytenoid muscle showed inflammatory degeneration, while the posterior cricoarytenoid and cricothyroid muscles showed classical changes of denervation. These findings should have clinical significance in the timing of reinnervation procedures.

scholarly journals Aging of skeletal muscle: a 12-yr longitudinal study

2000 ◽  
Vol 88 (4) ◽  
pp. 1321-1326 ◽  
Author(s):  
Walter R. Frontera ◽  
Virginia A. Hughes ◽  
Roger A. Fielding ◽  
Maria A. Fiatarone ◽  
William J. Evans ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Strength ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Analysis Of Covariance ◽  
Muscle Size ◽  
Type I ◽  
Cross Sectional ◽  
Age Related ◽  
Change In Mean

The present study examines age-related changes in skeletal muscle size and function after 12 yr. Twelve healthy sedentary men were studied in 1985–86 (T1) and nine (initial mean age 65.4 ± 4.2 yr) were reevaluated in 1997–98 (T2). Isokinetic muscle strength of the knee and elbow extensors and flexors showed losses ( P < 0.05) ranging from 20 to 30% at slow and fast angular velocities. Computerized tomography ( n = 7) showed reductions ( P < 0.05) in the cross-sectional area (CSA) of the thigh (12.5%), all thigh muscles (14.7%), quadriceps femoris muscle (16.1%), and flexor muscles (14.9%). Analysis of covariance showed that strength at T1 and changes in CSA were independent predictors of strength at T2. Muscle biopsies taken from vastus lateralis muscles ( n = 6) showed a reduction in percentage of type I fibers (T1 = 60% vs. T2 = 42%) with no change in mean area in either fiber type. The capillary-to-fiber ratio was significantly lower at T2 (1.39 vs. 1.08; P = 0.043). Our observations suggest that a quantitative loss in muscle CSA is a major contributor to the decrease in muscle strength seen with advancing age and, together with muscle strength at T1, accounts for 90% of the variability in strength at T2.

scholarly journals Sex-Dependent Effects of Quadriceps Fat Content on Single Muscle Fiber Size in Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 127-128
Author(s):  
Chad Straight ◽  
Joseph Gordon ◽  
Aurora Foster ◽  
Nicholas Remillard ◽  
Bruce Damon ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Older Women ◽  
Muscle Fiber ◽  
Vigorous Physical Activity ◽  
Knee Extensor ◽  
Single Fiber ◽  
Type I ◽  
Cross Bridge ◽  
Fiber Size ◽  
And Function

Abstract Evidence suggests that ectopic fat deposition interferes with skeletal muscle structure and function, but few studies have examined underlying morphological and contractile properties at the single fiber level. Healthy older (65-75 y) men (n=9) and women (n=9) underwent dynamometry for assessment of knee extensor maximal torque, water-fat magnetic resonance imaging to quantify quadriceps muscle cross-sectional area (CSA) and fat fraction (FF), and vastus lateralis biopsies to determine morphology and function of type I and II muscle fibers. Despite similar body mass indices (24.4±1.3 vs. 24.6±0.5 kg∙m2, p=0.93) and daily moderate-to-vigorous physical activity (46±7 vs. 41±9 min∙d-1, p=0.67), women had greater FF (9.0±0.3 [range: 7.6-10.6] vs. 7.9±0.4 [6.0-9.7] %, p=0.04) than men, indicating increased adipose tissue deposition in skeletal muscle. Women also had smaller quadriceps CSA (39.8±1.8 vs. 57.9±1.3 cm2, p=0.01), specific torque (1.5±0.1 vs. 1.9±0.1 Nm∙cm-2, p=0.01) and type II fiber CSA (3,943±312 [2,350-5,140] vs. 5,352±384 [3,560-6,590] µm2, p=0.01) than men. Type I CSA did not differ by sex (4,918±228 [3,740-5,600] vs. 5,630±440 [3,640-7,670] µm2, p=0.19). In older women, FF was inversely associated with single fiber CSA in type I (r= -0.81, p=0.02) and II (r= -0.76, p=0.03) fibers, and tended to be associated with slower myosin-actin cross-bridge kinetics (longer myosin attachment time) in type I fibers (r=0.65, p=0.08). These relationships were not observed in men. Overall, healthy older women have greater intramuscular fat than men, which may contribute to sex-specific effects on knee extensor specific torque through differences in muscle fiber size and cross-bridge kinetics.

Sign in / Sign up

Export Citation Format

Share Document