Relationship between capillary angiogenesis, fiber type, and fiber size in chronic systemic hypoxia

2001 ◽  
Vol 281 (1) ◽  
pp. H241-H252 ◽  
Author(s):  
D. Deveci ◽  
Janice M. Marshall ◽  
S. Egginton
Keyword(s):  
Skeletal Muscles ◽  
Fiber Type ◽  
Capillary Density ◽  
Mechanical Stimulus ◽  
Type I ◽  
Systemic Hypoxia ◽  
Fiber Size ◽  
Male Wistar Rats ◽  
Capillary Angiogenesis ◽  
Type I Fibers

Whether chronic hypoxia causes angiogenesis in skeletal muscle is controversial. Male Wistar rats, 5–6 wk of age, were kept at constant 12% O2 for 3 wk, and frozen sections of their postural soleus (SOL), phasic extensor digitorum longus (EDL), and tibialis anterior (TA) muscles were compared with those of normoxic controls. Capillary supply increased in SOL muscles [capillary-to-fiber ratio (C/F) = 2.55 ± 0.09 hypoxia vs. 2.17 ± 0.06 normoxia; capillary density (CD) = 942 ± 14 hypoxia vs. 832 ± 20 mm−2 normoxia, P < 0.01] but not in EDL muscles (C/F = 1.44 ± 0.04 hypoxia vs. 1.42 ± 0.04 normoxia; CD = 876 ± 52 hypoxia vs. 896 ± 24 mm−2 normoxia). The predominantly glycolytic cortex of TA muscles showed higher C/F after hypoxia (1.79 ± 0.09 vs. 1.53 ± 0.05 normoxia, P < 0.05), whereas the mainly oxidative TA core with smaller fibers showed no change in capillarity. The region of the SOL muscle with large-sized (mean fiber area 2,843 ± 128 μm2) oxidative fibers (90% type I) had a higher C/F (by 30%) and CD (by 25%), whereas there was no angiogenesis in the region with sparse (76%) and smaller-sized (2,200 ± 85 μm2) type I fibers. Thus systemic hypoxia differentially induces angiogenesis between and within hindlimb skeletal muscles, with fiber size contributing either directly (via a metabolic stimulus) or indirectly (via a mechanical stimulus) to the process.

Capillary and size interrelationships in developing rat diaphragm, EDL, and soleus muscle fiber types

1989 ◽  
Vol 256 (1) ◽  
pp. C50-C58 ◽  
Author(s):  
D. Smith ◽  
H. Green ◽  
J. Thomson ◽  
M. Sharratt
Keyword(s):  
Muscle Fiber ◽  
Time Course ◽  
Fiber Type ◽  
Capillary Density ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Fiber Area ◽  
Male Wistar Rats ◽  
Type I Fibers

The effects of maturation on the interrelationship between skeletal muscle fiber area and capillarization was investigated in specific fiber types (I, IIa, IIb, IIc) of male Wistar rats at seven developmental periods ranging from 8 to 85 days postnatal. Fiber type specific developmental properties were compared in three different muscles, the diaphragm (DIA), extensor digitorum longus (EDL), and soleus (SOL), which are known to differ widely in function. All fiber types in each of the three muscles examined exhibited large increases in area (FA), the magnitude and time course of the increase being related to both the type of fiber and the muscle in which the fiber was located. For type I fibers, areas increased from 3- to 18-fold (SOL greater than EDL greater than DIA), whereas in type IIa fibers, area increased ranged between 5- to 11-fold (SOL greater than EDL greater than DIA). Growth rates in IIb fibers were more homogeneous between muscles ranging from 11- to 14-fold. Capillarization, as indicated by the capillary contacts per fiber (CC), increased in all fiber types regardless of muscle origin. These increases ranged between 1.7- and 2.2-fold for type I fibers, between 2.4- and 2.5-fold for type IIa fibers, and between 2.0- and 3.0-fold for type IIb fibers. In general, capillary density expressed as the ratio of the number of capillary contacts divided by the fiber area (CC/FA) progressively declined in all fiber types with age. The rate of the decline in CC/FA was mediated in large part by the changes in fiber area.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Myofibrillar ATPase histochemistry of rat skeletal muscles: a "two-dimensional" quantitative approach.

1991 ◽  
Vol 39 (5) ◽  
pp. 589-597 ◽  
Author(s):  
A Lind ◽  
D Kernell
Keyword(s):  
Skeletal Muscles ◽  
Biceps Brachii ◽  
Fiber Type ◽  
Type I ◽  
Fiber Types ◽  
Two Dimensional ◽  
Myofibrillar Atpase ◽  
Serial Sections ◽  
Staining Methods ◽  
Type I Fibers

In histochemical investigations of skeletal muscle, the fibers are commonly classified into three types according to their staining for myofibrillar ATPase (mATPase). In serial sections of skeletal muscles from normal Wistar rats, we compared two common staining methods for mATPase: (a) an ac-ATPase technique, with pre-incubation at pH 4.7, and (b) a fixed alk-ATPase technique, using treatment with 5% paraformaldehyde followed by pre-incubation at pH 10.4. In addition, the same fibers were stained in subsequent serial sections for succinate dehydrogenase (SDH) activity. Staining intensities were objectively evaluated by microphotometric measurements of optical density. Combining both mATPase methods in consecutive serial sections ("two-dimensional approach") led to the identification of four distinct clusters of fibers: Types I, IIA, and two subgroups of Type IIB, as separated by their staining densities for fixed alk-ATPase (IIBd dark, IIBm moderate). The mean intensity of SDH staining per fiber type, as measured in the central core of the fibers, was ranked such that IIA greater than I greater than IIBd greater than IIBm. The analyzed muscles (tibialis anterior, biceps brachii) were markedly heterogeneous with respect to the topographic distribution of different fiber types. In comparison to other muscle portions, the regions containing Type I fibers ("red" portions) showed a higher IIBd vs IIBm ratio and more intense SDH staining for either subtype of the IIB fibers. The IIBd fibers probably correspond to the Type 2X fibers of Schiaffino et al.

scholarly journals Transitional Hybrid Skeletal Muscle Fibers in Rat Soleus Development

2019 ◽  
Vol 67 (12) ◽  
pp. 891-900 ◽  
Author(s):  
Lauren Larson ◽  
Jessica Lioy ◽  
Jordan Johnson ◽  
Scott Medler
Keyword(s):  
Skeletal Muscles ◽  
Muscle Development ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Distinct Type ◽  
Triceps Surae ◽  
Type I ◽  
Myosin Heavy Chain Isoform ◽  
The Individual ◽  
Type I Fibers

Skeletal muscles comprise hundreds of individual muscle fibers, with each possessing specialized contractile properties. Skeletal muscles are recognized as being highly plastic, meaning that the physiological properties of single muscle fibers can change with appropriate use. During fiber type transitions, one myosin heavy chain isoform is exchanged for another and over time the fundamental nature of the fiber adapts to become a different fiber type. Within the rat triceps surae complex, the soleus muscle starts out as a muscle comprised of a mixture type IIA and type I fibers. As neonatal rats grow and mature, the soleus undergoes a near complete transition into a muscle with close to 100% type I fibers at maturity. We used immunohistochemistry and single fiber SDS-PAGE to track the transformation of type IIA into type I fibers. We found that transitioning fibers progressively incorporate new myofibrils containing type I myosin into existing type IIA fibers. During this exchange, distinct type I-containing myofibrils are segregated among IIA myofibrils. The individual myofibrils within existing muscle fibers thus appear to represent the functional unit that is exchanged during fiber type transitions that occur as part of normal muscle development:

Myosin Heavy Chain Composition and Fiber Size of the Cricopharyngeus Muscle in Patients with Achalasia and Normal Subjects

2007 ◽  
Vol 116 (9) ◽  
pp. 643-646 ◽  
Author(s):  
Melinda V. Davis ◽  
Albert L. Merati ◽  
Safwan S. Jaradeh ◽  
Joel H. Blumin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Normal Subjects ◽  
Type I ◽  
Cricopharyngeus Muscle ◽  
Type Composition ◽  
Fiber Size ◽  
The Difference ◽  
Type I Fibers

Objectives: Cricopharyngeal achalasia (CA) can be defined as inadequate opening of the cricopharyngeus muscle (CPM) resulting in dysphagia. Myosin heavy chain (MHC) isoform fiber type composition and size are key determinants of muscle function. These parameters have not been described in CA. It is hypothesized that there is a difference between the MHC isoform composition of the CPM in patients with the clinical diagnosis of CA and that in normal subjects. Methods: Patients who had received prior botulinum were excluded. The MHC fiber type composition and size in patients and cadaveric controls were determined by adenosine triphosphatase staining and image analysis. Results: The CPMs of 12 CA patients (6 male, 6 female; mean age, 61 years) and 5 control cadaveric subjects (3 male, 2 female; mean age, 67 years) were analyzed. There were relatively fewer type I fibers (67%) in patients with CA than in controls (81%), but the difference was not significant (p = 18). Type I fibers were slightly smaller in CA patients (38.7 μm) than in controls (47.2 μm), but this was not significantly different (p > 05). Of the 12 CA patients, 3 had type II predominance, a feature not seen in normal subjects. Conclusions: Patients with CA had relatively fewer type I fibers, although the difference was not statistically significant. The MHC isoform composition and fiber size were not different between CA patients and normal subjects. This is the first report to characterize the CPM in patients with CA.

Histochemical and enzymatic characteristics of skeletal muscle in master athletes

1990 ◽  
Vol 68 (5) ◽  
pp. 1896-1901 ◽  
Author(s):  
A. R. Coggan ◽  
R. J. Spina ◽  
M. A. Rogers ◽  
D. S. King ◽  
M. Brown ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Capillary Density ◽  
Type I ◽  
Master Athletes ◽  
Lactate Dehydrogenase Activity ◽  
Older Athletes ◽  
Fiber Type Distribution ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Type I Fibers

Many older athletes are capable of endurance performances equal to those of young runners who have higher maximal O2 uptakes (VO2max). To determine whether this is a result of differences in skeletal muscle characteristics, gastrocnemius muscle biopsy samples were obtained from eight master athletes [aged 63 +/- 6 (SD) yr] and eight young (aged 26 +/- 3 yr) runners. The young runners were matched with the master athletes for 10-km running performance and for their volume, pace, and type of training. Despite similar 10-km run times, VO2max was 11% lower (P less than 0.05) in the master athletes. Fiber type distribution did not differ between groups, with both groups having 60% type I and very few type IIb fibers. Succinate dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase activities, however, were 31 and 24% higher in the master athletes compared with the matched young runners, whereas lactate dehydrogenase activity was 46% lower (all P less than 0.05). The capillary-to-fiber ratio was also greater in the master athletes; however, capillary density was similar in the two groups, because of the master athletes' 34% larger (P less than 0.05) type I fibers. These differences in skeletal muscle characteristics may explain the master athletes' ability to perform as well as some young runners despite having a lower VO2max.

scholarly journals Critical power is positively related to skeletal muscle capillarity and type I muscle fibers in endurance-trained individuals

2018 ◽  
Vol 125 (3) ◽  
pp. 737-745 ◽  
Author(s):  
Emma A. Mitchell ◽  
Neil R. W. Martin ◽  
Stephen J. Bailey ◽  
Richard A. Ferguson
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Transport ◽  
Skeletal Muscles ◽  
Critical Power ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Type I ◽  
Fiber Types ◽  
Aerobic Function ◽  
Type I Fibers

The asymptote [critical power (CP)] and curvature constant ( W′) of the hyperbolic power-duration relationship can predict performance within the severe-intensity exercise domain. However, the extent to which these parameters relate to skeletal muscle morphology is less clear, particularly in endurance-trained individuals, who, relative to their lesser-trained counterparts, possess skeletal muscles that can support high levels of oxygen transport and oxidative capacity, i.e., elevated type I fiber proportion and cross-sectional area (CSA) and capillarity. Fourteen endurance-trained men performed a maximal incremental test to determine peak oxygen uptake (V̇o2peak; 63.2 ± 4.1 ml·min−1·kg−1, mean ± SD) and maximal aerobic power (406 ± 63 W) and three to five constant-load tests to task failure for the determination of CP (303 ± 52 W) and W′ (17.0 ± 3.0 kJ). Skeletal muscle biopsies were obtained from the vastus lateralis and analyzed for percent proportion of fiber types, CSA, and indexes of capillarity. CP was positively correlated with the percent proportion ( r = 0.79; P = 0.001) and CSA ( r = 0.73; P = 0.003) of type I fibers, capillary-to-fiber ratio ( r = 0.88; P < 0.001), and capillary contacts around type I fibers ( r = 0.94; P < 0.001) and type II fibers ( r = 0.68; P = 0.008). W′ was not correlated with any morphological variables. These data reveal a strong positive association between CP and skeletal muscle capillarity. Our findings support the assertion that CP is an important parameter of aerobic function and offer novel insights into the physiological bases of CP. NEW & NOTEWORTHY This investigation demonstrated very strong positive correlations between critical power and skeletal muscle capillarity, particularly around type I fibers, and type I fiber composition. These correlations were demonstrated in endurance-trained individuals expected to possess well-adapted skeletal muscles, such as high levels of oxygen transport structures and high oxidative capacities, supporting the view that critical power is an important parameter of aerobic function. In contrast, the curvature constant W′ was not associated with fiber type composition or capillarity.

scholarly journals Effects of long-term physical exercise in the skeletal muscles of rats

2017 ◽  
Vol 34 (04) ◽  
pp. 226-231 ◽  
Author(s):  
J. Adala ◽  
G. Campos
Keyword(s):  
Physical Exercise ◽  
Skeletal Muscles ◽  
Wistar Rats ◽  
Experimental Period ◽  
Type I ◽  
Muscle Weight ◽  
Male Wistar Rats ◽  
Edl Muscle ◽  
Type I Fibers

Abstract Introdcution: The effects oflong-term physical exercise in the skeletal muscles were evaluated. Methods: 30 male Wistar rats, 25 days old each, were divided in 2 groups: trained (TG, n=21) and sedentary (SG, n=9). The TG group was subdivided in 3 groups: TGI, TGII and TGIII, n=7 in each group, and the SG was also subdivided in 3 groups: SGI, SGII and SGIII, n=3. The animals of the TG (I, II and III) performed running exercise on a electric running machine for 3, 6 and 9 weeks respectively. The animals of the sedentary groups remained without any exercise. After the experimental period the soleus (SOL), the extensor digitorum longus (EDL) and the plantaris (PL) muscles were extracted, weighed and analyzed by the histochemichal technique of mATPase to observe possible changes. Results: The TGIII showed a significant increase in the absolute values of muscle weight when compared to the TGI and TGII. There was an increase in the distribution of type I fibers and a decrease in types IIC and IIA in the SOL muscle. The EDL muscle showed an increase in IIA fibers and a decrease in IID IIB types. As for the PL muscle there was an increase in types IIA and IIAD and a decrease in IID type ibers. Conclusion: Physical exercise causes changes in the distribution of iber types in the skeletal muscles of rats and confirms the capacity of the fibers to adapt to the requirements of the proposed physical exercise in order to achieve a better performance.

Skeletal muscle composition in dietary obesity-susceptible and dietary obesity-resistant rats

1992 ◽  
Vol 262 (4) ◽  
pp. R684-R688 ◽  
Author(s):  
J. Abou Mrad ◽  
F. Yakubu ◽  
D. Lin ◽  
J. C. Peters ◽  
J. B. Atkinson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Gastrocnemius Muscle ◽  
Fiber Type ◽  
Type I ◽  
Total Weight Gain ◽  
Bottom Quartile ◽  
Male Wistar Rats ◽  
Dietary Obesity ◽  
Type I Fibers

The intent of this study was to determine whether a relationship exists between susceptibility to high-fat diet (HFD)-induced obesity and skeletal muscle fiber type. Forty-four adult male Wistar rats were given ad libitum access to a HFD (60% of calories from fat) for 4 wk. Rats were then grouped into quartiles for total weight gain, and the top-quartile [obesity prone (OP)] rats were compared with the bottom-quartile [obesity resistant (OR)] rats. OP rats gained 1.5 times as much weight as OR rats. OR rats had a significantly higher proportion of type I muscle fibers in the medial head of the gastrocnemius muscle than OP rats both before (determined from a muscle biopsy) and after the HFD feeding period. A greater proportion of type I fibers may be associated with a greater capacity for fat oxidation, which would favor resistance to body fat accumulation. Preexisting differences in muscle fiber composition may play a role in determining susceptibility to dietary obesity.

Free mobilization and low- to high-intensity exercise in immobilization-induced muscle atrophy

1998 ◽  
Vol 84 (4) ◽  
pp. 1418-1424 ◽  
Author(s):  
Pekka Kannus ◽  
Laszlo Jozsa ◽  
Teppo L. N. Järvinen ◽  
Martti Kvist ◽  
Toini Vieno ◽  
...  
Keyword(s):  
High Intensity ◽  
Relative Number ◽  
Capillary Density ◽  
High Intensity Exercise ◽  
Treadmill Running ◽  
Type I ◽  
Sprague Dawley ◽  
Fiber Size ◽  
Percent Area ◽  
Type I Fibers

After 3 wk of immobilization, the effects of free cage activity and low- and high-intensity treadmill running (8 wk) on the morphology and histochemistry of the soleus and gastrocnemius muscles in male Sprague-Dawley rats were investigated. In both muscles, immobilization produced a significant ( P < 0.001) increase in the mean percent area of intramuscular connective tissue (soleus: 18.9% in immobilized left hindlimb vs. 3.6% in nonimmobilized right hindlimb) and in the relative number of muscle fibers with pathological alterations (soleus: 66% in immobilized hindlimb vs. 6% in control), with a simultaneous significant ( P < 0.001) decrease in the intramuscular capillary density (soleus: mean capillary density in the immobilized hindlimb only 63% of that in the nonimmobilized hindlimb) and muscle fiber size (soleus type I fibers: mean fiber size in the immobilized hindlimb only 69% of that in the nonimmobilized hindlimb). Many of these changes could not be corrected by free remobilization, whereas low- and high-intensity treadmill running clearly restored the changes toward control levels, the effect being most complete in the high-intensity running group. Collectively, these findings indicate that immobilization-induced pathological structural and histochemical alterations in rat calf muscles are, to a great extent, reversible phenomena if remobilization is intensified by physical training. In this respect, high-intensity exercise seems more beneficial than low-intensity exercise.

Rostrocaudal pattern of fiber-type changes in an overloaded rat ankle extensor

1991 ◽  
Vol 71 (2) ◽  
pp. 558-564 ◽  
Author(s):  
P. F. Gardiner ◽  
B. J. Jasmin ◽  
P. Corriveau
Keyword(s):  
Fiber Type ◽  
Muscle Length ◽  
Similar Degree ◽  
Complex Nature ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Cross Sectional ◽  
Hypertrophic Response ◽  
Type I Fibers

Our aim was to quantify the overload-induced hypertrophy and conversion of fiber types (type II to I) occurring in the medial head of the gastrocnemius muscle (MG). Overload of MG was induced by a bilateral tenotomy/retraction of synergists, followed by 12–18 wk of regular treadmill locomotion (2 h of walking/running per day on 3 of 4 days). We counted all type I fibers and determined type I and II mean fiber areas in eight equidistant sections taken along the length of control and overloaded MG. Increase in muscle weights (31%), as well as in total muscle cross-sectional areas (37%) and fiber areas (type I, 57%; type II, 34%), attested to a significant hypertrophic response in overloaded MG. An increase in type I fiber composition of MG from 7.0 to 11.5% occurred as a result of overload, with the greatest and only statistically significant changes (approximately 70–100%) being found in sections taken from the most rostral 45% of the muscle length. Results of analysis of sections taken from the largest muscle girth showed that it significantly underestimated the extent of fiber conversion that occurred throughout the muscle as a whole. These data obtained on the MG, which possesses a compartmentalization of fiber types, support the notion that all fiber types respond to this model with a similar degree of hypertrophy. Also, they emphasize the complex nature of the adaptive changes that occur in these types of muscles as a result of overload.

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