Fiber number, area, and composition of mouse soleus muscle following enlargement

1985 ◽  
Vol 58 (2) ◽  
pp. 619-624 ◽  
Author(s):  
B. F. Timson ◽  
B. K. Bowlin ◽  
G. A. Dudenhoeffer ◽  
J. B. George
Keyword(s):  
Muscle Fiber ◽  
Soleus Muscle ◽  
Histological Section ◽  
Type I ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Male And Female ◽  
Female Mice ◽  
Fiber Area ◽  
Fiber Number

Muscle fiber number, cross-sectional area, and composition were studied in response to enlargement produced by synergistic ablation in the mouse soleus muscle. The effect of the location of a histological section on the number of fibers that appear in the section was also studied using the mouse soleus muscle. Enlargement was produced in the soleus muscle of 15 male and 15 female mice by ablation of the ipsilateral gastrocnemius muscle. Fiber counts, using the nitric acid digestion method, revealed no difference between control and enlarged muscles in male and female mice. Mean fiber area, determined by planimetry, was 49.1 and 34.5% greater following enlargement in male and female mice, respectively. Increase in muscle weight could be totally accounted for by the increase in fiber area following enlargement. A transformation of type II to type I fibers occurred following enlargement for both sexes. Counts of fibers from histological sections revealed that there was a progressive decrease in the fiber number as the section was moved from the belly to the distal end of the muscle. The results of these studies indicate that muscle enlargement in the mouse soleus muscle is due to hypertrophy of the existing muscle fibers.

Voluntary strength and muscle characteristics in untrained men and women and male bodybuilders

1987 ◽  
Vol 62 (5) ◽  
pp. 1786-1793 ◽  
Author(s):  
D. G. Sale ◽  
J. D. MacDougall ◽  
S. E. Alway ◽  
J. R. Sutton
Keyword(s):  
Muscle Fiber ◽  
Biceps Brachii ◽  
Peak Torque ◽  
Volume Density ◽  
Isokinetic Dynamometer ◽  
Cross Sectional ◽  
Fiber Area ◽  
Fiber Composition ◽  
Fiber Number ◽  
Voluntary Strength

Eight untrained women (F), 13 untrained men (M), and 11 male bodybuilders (BB) did maximal elbow flexions on an isokinetic dynamometer at velocities of 30, 120, 180, 240, and 300 degrees/s, from which impact torque (IT), peak torque (PT), and work (W) were measured. Biceps and total flexor cross-sectional area (CSA) were measured by computerized tomographic scanning. Muscle fiber area, fiber composition, and collagen volume density were determined from single needle biopsies of biceps brachii. Biceps fiber number was estimated as the ratio of biceps CSA (corrected for connective tissue) to mean fiber area. PT and W decreased at higher velocities in M and BB but not in F; consequently, the correlation between CSA and PT and W was lower at 300 degrees/s (r = 0.58, 0.60) than 30 degrees/s (r = 0.80, 0.79). The ratio of PT to flexor CSA was similar in all groups at 30 degrees/s, whereas F had greater ratios than M and BB at the remaining velocities. F had greater W/CSA ratios than M and BB at all velocities. IT increased at higher velocities in all groups; the increase was greater in F and M than in BB. In contrast to PT and W, the correlation between IT and CSA was greater at 300 degrees/s (r = 0.67) than 30 degrees/s (r = 0.58), and there were no differences among groups in the IT/CSA ratios. Flexor CSA correlated negatively with the ratio of IT, PT, and W to CSA. Muscle fiber composition failed to correlate with any measure of strength. M and BB had greater biceps area, fiber number, and fiber area than F.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Genetic and genomic analyses of musculoskeletal differences between BEH and BEL strains

2013 ◽  
Vol 45 (20) ◽  
pp. 940-947 ◽  
Author(s):  
Arimantas Lionikas ◽  
Audrius Kilikevicius ◽  
Lutz Bünger ◽  
Caroline Meharg ◽  
Andrew M. Carroll ◽  
...  
Keyword(s):  
Body Weight ◽  
Soleus Muscle ◽  
Muscle Growth ◽  
Morphological Characteristics ◽  
Nucleotide Polymorphisms ◽  
Causative Gene ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Fiber Number ◽  
Muscle Fiber Number

Berlin high (BEH) and Berlin low (BEL) strains selected for divergent growth differ threefold in body weight. We aimed at examining muscle mass, which is a major contributor to body weight, by exploring morphological characteristics of the soleus muscle (fiber number and cross sectional area; CSA), by analyzing the transcriptome of the gastrocnemius and by initiating quantitative trait locus (QTL) mapping. BEH muscles were four to eight times larger than those of BEL. In substrain BEH+/+, mutant myostatin was replaced with a wild-type allele; however, BEH+/+muscles still were two to four times larger compared with BEL. BEH soleus muscle fibers were two times more numerous ( P < 0.0001) and CSA was two times larger ( P < 0.0001) compared with BEL. In addition, soleus femoral attachment anomaly (SFAA) was observed in all BEL mice. One significant (Chr 1) and four suggestive (Chr 3, 4, 6, and 9) muscle weight QTLs were mapped in a 21-day-old F2 intercross ( n = 296) between BEH and BEL strains. The frequency of SFAA incidence in the F2 and in the backcross to BEL strain (BCL) suggested the presence of more than one causative gene. Two suggestive SFAA QTLs were mapped in BCL; however, their peak markers were not associated with the phenotype in F2. RNA-Seq analysis revealed 2,148 differentially expressed ( P < 0.1) genes and 45,673 single nucleotide polymorphisms and >2,000 indels between BEH+/+ and BEL males. In conclusion, contrasting muscle traits and genomic and gene expression differences between BEH and BEL strains provide a promising model for the search for genes involved in muscle growth and musculoskeletal morphogenesis.

scholarly journals Gonad-related factors promote muscle performance gain during postnatal development in male and female mice

2017 ◽  
Vol 313 (1) ◽  
pp. E12-E25 ◽  
Author(s):  
Vanessa Ueberschlag-Pitiot ◽  
Amalia Stantzou ◽  
Julien Messéant ◽  
Megane Lemaitre ◽  
Daniel J. Owens ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Postnatal Development ◽  
Muscle Fiber ◽  
Muscle Performance ◽  
Performance Gain ◽  
Related Factors ◽  
Muscle Weight ◽  
Male And Female ◽  
Female Mice ◽  
Muscle Contractile

To better define the role of male and female gonad-related factors (MGRF, presumably testosterone, and FGRF, presumably estradiol, respectively) on mouse hindlimb skeletal muscle contractile performance/function gain during postnatal development, we analyzed the effect of castration initiated before puberty in male and female mice. We found that muscle absolute and specific (normalized to muscle weight) maximal forces were decreased in 6-mo-old male and female castrated mice compared with age- and sex-matched intact mice, without alteration in neuromuscular transmission. Moreover, castration decreased absolute and specific maximal powers, another important aspect of muscle performance, in 6-mo-old males, but not in females. Absolute maximal force was similarly reduced by castration in 3-mo-old muscle fiber androgen receptor (AR)-deficient and wild-type male mice, indicating that the effect of MGRF was muscle fiber AR independent. Castration reduced the muscle weight gain in 3-mo mice of both sexes and in 6-mo females but not in males. We also found that bone morphogenetic protein signaling through Smad1/5/9 was not altered by castration in atrophic muscle of 3-mo-old mice of both sexes. Moreover, castration decreased the sexual dimorphism regarding muscle performance. Together, these results demonstrated that in the long term, MGRF and FGRF promote muscle performance gain in mice during postnatal development, independently of muscle growth in males, largely via improving muscle contractile quality (force and power normalized), and that MGFR and FGRF also contribute to sexual dimorphism. However, the mechanisms underlying MGFR and FGRF actions remain to be determined.

Contrasts in muscle and myofibers of elite male and female bodybuilders

1989 ◽  
Vol 67 (1) ◽  
pp. 24-31 ◽  
Author(s):  
S. E. Alway ◽  
W. H. Grumbt ◽  
W. J. Gonyea ◽  
J. Stray-Gundersen
Keyword(s):  
Lean Body Mass ◽  
Body Mass ◽  
Biceps Brachii ◽  
Body Height ◽  
Type I ◽  
Type Ii ◽  
Cross Sectional ◽  
Fiber Area ◽  
Fiber Number ◽  
Muscle Cross Sectional Area

Muscle cross-sectional area (CSA), fiber area, and fiber number were determined from the biceps brachii of eight elite male bodybuilders (MB) and five elite female bodybuilders (FB) who had similar training characteristics. Biceps CSA was obtained from computer tomographic scanning and corrected for noncontractile tissue. Biceps CSA was twofold greater in MB relative to FB and strongly correlated to lean body mass (R = 0.93). Biceps CSA expressed per kilogram lean body mass (LBM) or per centimeter body height (BH) was 35% greater in MB compared with FB. Most of the gender difference in muscle CSA was because of greater absolute mean fiber areas in MB (9,607 microns2) relative to FB (5,386 microns2); however, MB also had a significantly greater population of small type II fibers (less than 2,000 microns2) compared with FB. Type II fiber area/LBM averaged 1.6-fold greater in MB compared with FB; however, type I fiber area/LBM was similar between groups. Biceps CSA was positively correlated to fiber CSA (R = 0.75) and fiber number (R = 0.55). This suggests that adaptations to resistance training may be complex and involve fiber hypertrophy and fiber number (e.g., proliferation). Alternatively, since the muscle characteristics before training are not known, these apparent adaptations might be genetically determined attributes.

Fiber number and size in overloaded chicken anterior latissimus dorsi muscle

1983 ◽  
Vol 54 (5) ◽  
pp. 1292-1297 ◽  
Author(s):  
P. D. Gollnick ◽  
D. Parsons ◽  
M. Riedy ◽  
R. L. Moore
Keyword(s):  
Latissimus Dorsi ◽  
Histochemical Staining ◽  
Type I ◽  
Fiber Volume ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Relative Contribution ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Muscle Fiber Number

The relative contribution of increases in fiber area and number was evaluated in the chicken anterior latissimus dorsi (ALD) muscle in which enlargement was induced by hanging a weight on one wing. ALD muscles from wings to which weights had been attached for periods ranging from 6 to 65 days weighed an average of 105% (range 22–225%) more than control muscles. Total muscle fiber number, determined by direct counts after nitric acid digestion and fiber dissection, and the frequency of branched fibers were unchanged by muscular enlargement. Fiber cross-sectional area was greater (P less than 0.01) in the enlarged muscles. A close relationship existed (r = 0.78) between actual muscle weight and weight calculated as the product of fiber volume, total fiber number, and muscle density for the control and enlarged muscles. Histochemical staining revealed a conversion of type IIa to type I fibers in the stretched muscles. These results support the concept that skeletal muscle enlargement in response to chronic overload is produced by hypertrophy of preexisting fibers and not be a formation of new fibers.

Muscle fiber hypertrophy, hyperplasia, and capillary density in college men after resistance training

1996 ◽  
Vol 81 (5) ◽  
pp. 2004-2012 ◽  
Author(s):  
G. E. McCall ◽  
W. C. Byrnes ◽  
A. Dickinson ◽  
P. M. Pattany ◽  
S. J. Fleck
Keyword(s):  
Resistance Training ◽  
Muscle Fiber ◽  
Biceps Brachii ◽  
College Men ◽  
Capillary Density ◽  
Type I ◽  
Muscle Area ◽  
Cross Sectional ◽  
Fiber Number ◽  
Muscle Groups

McCall, G. E., W. C. Byrnes, A. Dickinson, P. M. Pattany, and S. J. Fleck. Muscle fiber hypertrophy, hyperplasia, and capillary density in college men after resistance training. J. Appl. Physiol. 81(5): 2004–2012, 1996.—Twelve male subjects with recreational resistance training backgrounds completed 12 wk of intensified resistance training (3 sessions/wk; 8 exercises/session; 3 sets/exercise; 10 repetitions maximum/set). All major muscle groups were trained, with four exercises emphasizing the forearm flexors. After training, strength (1-repetition maximum preacher curl) increased by 25% ( P < 0.05). Magnetic resonance imaging scans revealed an increase in the biceps brachii muscle cross-sectional area (CSA) (from 11.8 ± 2.7 to 13.3 ± 2.6 cm2; n = 8; P < 0.05). Muscle biopsies of the biceps brachii revealed increases ( P < 0.05) in fiber areas for type I (from 4,196 ± 859 to 4,617 ± 1,116 μm2; n = 11) and II fibers (from 6,378 ± 1,552 to 7,474 ± 2,017 μm2; n = 11). Fiber number estimated from the above measurements did not change after training (293.2 ± 61.5 × 103 pretraining; 297.5 ± 69.5 × 103 posttraining; n = 8). However, the magnitude of muscle fiber hypertrophy may influence this response because those subjects with less relative muscle fiber hypertrophy, but similar increases in muscle CSA, showed evidence of an increase in fiber number. Capillaries per fiber increased significantly ( P < 0.05) for both type I (from 4.9 ± 0.6 to 5.5 ± 0.7; n = 10) and II fibers (from 5.1 ± 0.8 to 6.2 ± 0.7; n = 10). No changes occurred in capillaries per fiber area or muscle area. In conclusion, resistance training resulted in hypertrophy of the total muscle CSA and fiber areas with no change in estimated fiber number, whereas capillary changes were proportional to muscle fiber growth.

Effects of cutaneous receptor stimulation on muscular atrophy developed in hindlimb unloading condition

2000 ◽  
Vol 89 (6) ◽  
pp. 2344-2351 ◽  
Author(s):  
Laurent De-Doncker ◽  
Florence Picquet ◽  
Maurice Falempin
Keyword(s):  
Soleus Muscle ◽  
Muscular Atrophy ◽  
Hindlimb Unloading ◽  
Type I ◽  
Fiber Types ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Wet Weight ◽  
Contraction Kinetics ◽  
Stimulation Of

The aim of this study was to investigate whether stimulation of the cutaneous mechanoreceptors of the rat foot sole could partially or totally prevent the soleus muscle atrophy developed after 14 days in hindlimb unloading conditions. Final experiments were achieved under deep anesthesia using pentobarbital sodium (60 mg/kg, ip injection). Atrophy was characterized by a significant decrease in muscle wet weight, fiber size, maximal twitch and tetanic tensions, contraction kinetics, and histochemical and electrophoretical changes. Our data demonstrate that the stimulation of these mechanoreceptors partially prevents the decrease in muscle weight (53%) and cross-sectional area of the soleus muscle (36%) and in all fiber types (type I: 31%; type Ic: 40%; type IIc: 49%; and type IIa: 44%) and also prevented the reductions in strength (peak twitch tension: 31%; peak tetanic tension: 25%). However, the decrease in contraction kinetics was not counteracted. Moreover, histochemical and electrophoretical changes were partially slowed. Thus our results suggest that stimulation of the sole mechanoreceptors can be used, in part, as a countermeasure to the muscular atrophy observed after a period of hindlimb unloading.

Acute fasting and fiber number in rat soleus muscle

1982 ◽  
Vol 53 (5) ◽  
pp. 1234-1238 ◽  
Author(s):  
D. Parsons ◽  
M. Riedy ◽  
R. L. Moore ◽  
P. D. Gollnick
Keyword(s):  
Body Weight ◽  
Soleus Muscle ◽  
Female Rats ◽  
Male Rats ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Weight Losses ◽  
Male And Female Rats ◽  
Fiber Number ◽  
Experimental Treatments

The influence of fasting on fiber number in the soleus muscle (SM) of weanling male and female rats was investigated. For female rats, comparisons were made among groups of animals fed normally, rats fasted and then fed until prefast body weight was regained, and animals that grew to maturity. For male rats, comparisons were made only between control and fasted groups. Prior to the experimental treatments the SM was surgically removed from one leg. There was a 40% loss in body weight after fasting. Although major weight losses occurred in most muscles and organs, there was no change in the SM. Over the same period SM weight increased 31% in normal animals. Total fiber number (direct counts after nitric acid digestion) was unaltered by the treatments. Although wide variation existed between animals, total fiber number between legs for the same animal was closely correlated (r = 0.98). SM weight for male rats calculated from fiber length, cross-sectional area, and total fiber number could account for from 91 to 99% of the total muscle weight. There was no change in fiber number from weaning to maturity. It is concluded that fiber number is unchanged by fasting or during normal maturation.

Regionalized adaptations and muscle fiber proliferation in stretch-induced enlargement

1989 ◽  
Vol 66 (2) ◽  
pp. 771-781 ◽  
Author(s):  
S. E. Alway ◽  
P. K. Winchester ◽  
M. E. Davis ◽  
W. J. Gonyea
Keyword(s):  
Muscle Fiber ◽  
Latissimus Dorsi ◽  
Volume Density ◽  
Cross Sectional ◽  
Adult Skeletal Muscle ◽  
Relative Contribution ◽  
Anterior Latissimus Dorsi ◽  
Fiber Number ◽  
Nitric Acid Digestion ◽  
Alpha Type

The relative contribution of increases in fiber area to stretch-induced muscle enlargement was evaluated in the slow tonic fibers of the anterior latissimus dorsi of adult Japanese quails. A weight corresponding to 10% of the bird's body mass was attached to one wing. Thirty days of stretch in 34 birds averaged 171.8 +/- 13.5% increase in muscle mass and 23.5 +/- 0.8% increase in muscle fiber length. The volume density of noncontractile tissue increased in middle and distal regions of stretch-enlarged muscles. Mean fiber cross-sectional area increased 56.7 +/- 12.3% in the midregion of stretched muscles. Further analysis indicated slow beta-fiber hypertrophy occurred in proximal, middle, and distal regions; however, fast alpha-type fiber hypertrophy was limited to middle regions of stretched muscles. Stretched muscles had a significant increase in the frequency of slow beta-fibers that were less than 500 microns 2 in all regions and fast alpha-type fibers in middle and distal regions. Total fiber number was determined after nitric acid digestion of connective tissue in 10 birds. Fiber number increased 51.8 +/- 19.4% in stretched muscle. These results are the first to clearly show that muscle fiber proliferation contributes substantially to adult skeletal muscle stretch-induced enlargement, although we do not know whether the responses of the slow tonic anterior latissimus dorsi might be similar or different from mammalian twitch muscle.

Mechanical stimulation of the plantar foot surface attenuates soleus muscle atrophy induced by hindlimb unloading in rats

2005 ◽  
Vol 99 (2) ◽  
pp. 739-746 ◽  
Author(s):  
Antonios Kyparos ◽  
Daniel L. Feeback ◽  
Charles S. Layne ◽  
Daniel A. Martinez ◽  
Mark S. F. Clarke
Keyword(s):  
Muscle Atrophy ◽  
Soleus Muscle ◽  
Gastrocnemius Muscle ◽  
Hindlimb Unloading ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Cross Sectional ◽  
Plantar Surface ◽  
Male Wistar Rats ◽  
Medial Gastrocnemius Muscle

Unloading-induced muscle atrophy occurs in the aging population, bed-ridden patients, and astronauts. This study was designed to determine whether dynamic foot stimulation (DFS) applied to the plantar surface of the rat foot can serve as a countermeasure to soleus muscle atrophy normally observed in hindlimb unloaded (HU) rats. Forty-four mature (6 mo old), male Wistar rats were randomly assigned to ambulatory control, HU alone, HU with active DFS (i.e., plantar contact with active inflation), HU with passive DFS (i.e., plantar contact without active inflation), and HU while wearing a DFS boot with no plantar contact groups. Application of active DFS during HU significantly counteracted the atrophic response by preventing ∼85% of the reduction in type I myofiber cross-sectional area (CSA) in the soleus while preventing ∼57% of the reduction in type I myofiber CSA and 43% of the reduction in type IIA myofiber CSA of the medial gastrocnemius muscle. Wearing of a DFS boot without active inflation prevented myofiber atrophy in the soleus of HU animals in a fashion similar to that observed in HU animals that wore an actively inflated DFS boot. However, when a DFS boot without plantar surface contact was worn during HU, no significant protection from HU-induced myofiber atrophy was observed. These results illustrate that the application of mechanical foot stimulation to the plantar surface of the rat foot is an effective countermeasure to muscle atrophy induced by HU.

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