Absence of regional differences in the size and oxidative capacity of diaphragm muscle fibers

1987 ◽  
Vol 63 (3) ◽  
pp. 1076-1082 ◽  
Author(s):  
G. C. Sieck ◽  
R. D. Sacks ◽  
C. E. Blanco
Keyword(s):  
Muscle Fibers ◽  
Continuous Distribution ◽  
Oxidative Capacity ◽  
Cross Sectional Area ◽  
Diaphragm Muscle ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Twitch

The oxidative capacity and cross-sectional area of muscle fibers were compared between the costal and crural regions of the cat diaphragm and across the abdominal-thoracic extent of the muscle. Succinate dehydrogenase (SDH) activity of individual fibers was quantified using a microphotometric procedure implemented on an image-processing system. In both costal and crural regions, population distributions of SDH activities were unimodal for both type I and II fibers. The continuous distribution of SDH activities for type II fibers indicated that no clear threshold exists for the subclassification of fibers based on differences in oxidative capacity (e.g., the classification of fast-twitch glycolytic and fast-twitch oxidative glycolytic fiber types). No differences in either SDH activity or cross-sectional area were noted between fiber populations of the costal and crural regions. Differences in SDH activity and cross-sectional area were noted, however, between fiber populations located on the abdominal and thoracic sides of the costal region. Both type I and II fibers on the abdominal side of the costal diaphragm were larger and more oxidative than comparable fibers on the thoracic side.

scholarly journals Denervation effects on myonuclear domain size of rat diaphragm fibers

2006 ◽  
Vol 100 (5) ◽  
pp. 1617-1622 ◽  
Author(s):  
Bharathi Aravamudan ◽  
Carlos B. Mantilla ◽  
Wen-Zhi Zhan ◽  
Gary C. Sieck
Keyword(s):  
Fiber Type ◽  
Cross Sectional Area ◽  
Diaphragm Muscle ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Rat Diaphragm ◽  
Cross Sectional ◽  
Fiber Size ◽  
Myonuclear Domain

Denervation (DNV) of rat diaphragm muscle (DIAm) leads to selective atrophy of type IIx and IIb fibers, whereas the cross-sectional area of type I and IIa fibers remains unchanged or slightly hypertrophied. DIAm DNV also increases satellite cell mitotic activity and myonuclear apoptosis. Similar to other skeletal muscles, DIAm fibers are multinucleated, and each myonucleus regulates the gene products in a finite fiber volume, i.e., myonuclear domain (MND). MND size varies across DIAm fiber types in rank order, I < IIa < IIx < IIb [fiber type based on myosin heavy chain isoform expression]. We hypothesized that, after DNV, the total number of myonuclei per fiber does not change and, accordingly, that MND changes proportionately to the change in fiber size regardless of fiber type. Adult rats underwent unilateral (right side) DIAm DNV, and after 2 wk single fibers were dissected. Fiber cross-sectional area, myonuclear number, and MND were measured by confocal microscopy, and these values in DNV DIAm were compared with those obtained in controls. After DNV, type I fibers hypertrophied, type IIa fiber size was unchanged, and type IIx and IIb fibers atrophied compared with control. The total number of myonuclei per fiber was not affected by DNV. Accordingly, after DNV, type I fiber MND increased by 25%, whereas it decreased in type IIx and IIb fibers by 50 and 70%, respectively. These results suggest that MND is not maintained after DNV-induced DIAm fiber hypertrophy or atrophy. These results are interpreted with respect to consequent effects of DNV on myonuclear transcriptional activity and protein turnover.

SDH and actomyosin ATPase activities of different fiber types in rat diaphragm muscle

1995 ◽  
Vol 79 (5) ◽  
pp. 1629-1639 ◽  
Author(s):  
G. C. Sieck ◽  
W. Z. Zhan ◽  
Y. S. Prakash ◽  
M. J. Daood ◽  
J. F. Watchko
Keyword(s):  
Atpase Activity ◽  
Rank Order ◽  
Cross Sectional Area ◽  
Diaphragm Muscle ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Rat Diaphragm ◽  
Cross Sectional ◽  
Actomyosin Atpase

In the rat diaphragm muscle, the histochemical classification of type I, IIa, IIb, or IIx fibers was correlated with myosin heavy chain (MHC) immunoreactivity. Expression of MHC isoforms in single dissected fibers was also assessed electrophoretically. Most fibers (approximately 86%) expressed a single MHC isoform, and when present, coexpression of MHC-2X and MHC-2B isoforms was most prevalent. Type I and IIa fibers were the smallest, type IIb fibers were the largest, and type IIx fibers were intermediate. Succinate dehydrogenase (SDH) and calcium-activated myosin adenosinetriphosphatase (actomyosin ATPase) activities were measured with quantitative histochemical procedures. Type I and IIa fibers had the highest SDH activities, followed in rank order by type IIx and IIb fibers. Type I fibers had the lowest actomyosin ATPase activity, followed in rank order by type IIa, IIx, and IIb fibers. Across all fibers, there was an inverse relationship between fiber SDH activity and cross-sectional area and a positive correlation between fiber actomyosin ATPase activity and cross-sectional area. The SDH and actomyosin ATPase activities of muscle fibers were also inversely correlated. These phenotypic differences in SDH and ATPase activities may be important in determining the contractile and fatigue properties of different fiber types in the rat diaphragm muscle.

Rat diaphragm during postnatal development. I. Changes in distribution of muscle fibre type and in oxidative potential

1996 ◽  
Vol 8 (3) ◽  
pp. 391 ◽  
Author(s):  
MD Fratacci ◽  
M Levame ◽  
A Rauss ◽  
H Bousbaa ◽  
G Atlan
Keyword(s):  
Muscle Fibre ◽  
Fibre Type ◽  
Oxidative Capacity ◽  
Cross Sectional Area ◽  
Fibre Types ◽  
Type I ◽  
Sectional Area ◽  
Rat Diaphragm ◽  
Oxidative Potential ◽  
Cross Sectional

The changes occurring in the histochemical characteristics of the rat diaphragm during the postnatal period were examined. Fibre-type distribution, fibre oxidative capacity, i.e. succinate-dehydrogenase (SDH) activity, and cross-sectional area were compared in the costal (COS) and crural (CRU) regions, and across their abdominal and thoracic surfaces. The proportions of type I and IIb fibres in both COS and CRU increased with age, while the proportion of type IIa fibres progressively decreased. For COS, fibre distribution was homogeneous over the entire muscle and did not change after 4 weeks. For CRU, it was heterogeneous with a higher proportion of type I fibres on the thoracic surface as from the first week. All fibre types significantly increased in cross-sectional area between 1 and 8 weeks, with no significant differences in COS and CRU. Mean SDH activity did not differ between COS and CRU or across the muscles. Mean SDH activities-were low and identical in all fibre types at birth, and then increased, peaking at the 6th week in type I and IIa fibres. When total muscle fibre oxidative capacity was calculated from an index including fibre-type proportion, cross-sectional area and mean SDH activity, it was significantly higher at 1 than at 8 weeks after birth; this might have functional implications for the newborn.

scholarly journals Morphological peculiarities of neuromuscular junctions among different fiber types: Effect of exercise

2017 ◽  
Vol 27 (3) ◽  
Author(s):  
Teet Seene ◽  
Maria Umnova ◽  
Priit Kaasik
Keyword(s):  
Axon Terminal ◽  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Thin Sections ◽  
Axon Terminals ◽  
Ultrastructural Studies

The aim of our research was to examine whether there are differences in the morphology of neuromuscular junctions of different types of muscle fibers in rodents, and after their adaptation to six weeks endurance exercise training. After 5-day acclimation, Wistar rats were subjected to run with the speed 35 m/min during 6 week, 5 days per week and the training volume reached 60 min per day. Muscle samples for ultrastructural studies were fixed, dehydrated and embedded in Epon-812. Ultra-thin sections were cut from longitudinally and transversely oriented blocs, using 4 blocks from each animal. The area of axon terminals on fast- twitch fibers is 1.5 time large (p&lt;0.001) and the perimeter of terminals is 1.7 time large in comparison with slow- twitch oxidative fibers (p&lt;0.001) in control group. There are correlation between cross-sectional area of different muscle fibers and length of axon terminals (r=0.72), between cross-sectional area and with of axon terminal (r=-0.62), and between turnover rate of contractile proteins and length of axon terminal (r=0.75). Fast remodeling of synapse on oxidative and oxidative-glycolytic muscle fibers during endurance training seems to guarantees the intensive renewal of the structures of muscle fibers with higher oxidative capacity.

scholarly journals Comparison of M.Semitendinosus Morphometry and Structure in Gilts and Barrows at Market Age

2016 ◽  
Vol 66 (1) ◽  
pp. 132-137
Author(s):  
Ivana Božičković ◽  
Duško Vitorović ◽  
Miloš Blagojević ◽  
Ivana Nešić ◽  
Slavoljub Jović ◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Histological Structure ◽  
Fiber Types ◽  
Sectional Area ◽  
Morphometric Characteristics ◽  
Cross Sectional ◽  
Fiber Number ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Very High

AbstractThe aim of this paper was to investigate the differences in morphometric characteristics and histological structure of m. semitendinosus, between gilts and barrows of German Landrace breed at the end of the fattening period. Morphometric characteristics (weight, length, diameter and cross sectional area) of m. semitendinosus were not significantly different, while gender as a factor influenced the histological properties of this muscle. A very high statistical difference (p<0.01) in the total number of muscle fibers in m. semitendinosus was determined, with gilts having a higher total fiber number. The cross sectional area of fast twitch oxidative (FTO) fibers was significantly higher (p<0.05) in barrows. Gender did not affect the distribution of different fiber types: in both gender, the most present fiber types (48-52 %) were fast twitch glycolitic (FTG), FTO fibers represented 27-30 % of the total fiber number, while slow twitch oxidative fibers (STO) were the least represented (≈ 20 %).

Effects of starvation and refeeding on adult male rat diaphragm contractility, fatigue, and fiber types

1993 ◽  
Vol 74 (2) ◽  
pp. 742-749 ◽  
Author(s):  
D. J. Prezant ◽  
D. E. Valentine ◽  
H. H. Kim ◽  
E. I. Gentry
Keyword(s):  
Fatigue Resistance ◽  
Cross Sectional Area ◽  
Male Rats ◽  
Male Rat ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional ◽  
Type Ii Fibers

The effects of 4.5 days of acute starvation, either alone or followed by refeeding (ad libitum), on diaphragm contractility, fatigue, and fiber types were studied in male rats. Contractility and fatigue resistance indexes were measured in an in vitro costal diaphragm strip preparation with direct stimulation at 37 degrees C. Compared with controls, starvation produced a 28 +/- 1% (P < 0.001) reduction in body weight and an 18 +/- 4% (P < 0.001) reduction in costal diaphragm weight. Twitch and tetanic tensions (normalized for weight or cross-sectional area) were not reduced by starvation. Starvation produced significant increases in fatigue resistance indexes after a 5-Hz stimulation paradigm but not after a 100-Hz paradigm, supporting the hypothesis that fatigue resistance is dependent on the energy demand of a given paradigm. The proportions of type I and type II fibers were similar between diaphragms of starved and control rats, but the cross-sectional area of type II fibers decreased significantly by 18 +/- 7% (P < 0.01). Thus, despite the significant decrease in diaphragm weight after starvation, contractility was preserved and fatigue resistance was increased (low-output paradigm). This is consistent with the decrease in type II fiber area. Refeeding restored all parameters so that there were no longer significant differences in body or diaphragm weight, contractility, fatigue, or fiber types.

Free autografting of entire limb muscles in the cat: histochemistry and biochemistry

1978 ◽  
Vol 44 (3) ◽  
pp. 431-437 ◽  
Author(s):  
L. C. Maxwell ◽  
J. A. Faulkner ◽  
S. A. Mufti ◽  
A. M. Turowski
Keyword(s):  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Succinate Dehydrogenase Activity ◽  
Cross Sectional ◽  
The Mean ◽  
Fast Twitch

Fifty extensor digitorium longus muscles of 25 cats were autografted, 33 with and 17 without prior denervation. After 50 days, no significant differences were observed between predenervated and nonpredenervated autografts. Autografted muscles weighed 48% of the weight of control muscles. Few original muscle fibers survived and within 2 wk autografts contained regenerating muscle fibers. The mean cross-sectional area of muscle fibers in the autografts reached 125% of the value for control nontransplanted muscles. The mean percentage of fibers classified high oxidative in autografted muscles was 67% of values for control muscles. SDH activity of autografted muscle homogenates reached 55% of control values. Up to 60 days after surgery autografts had only fast-twitch fibers. At 170 days autografts remained 95% fast twitch in composition. Revascularization began within 4 days, but the capillary to fiber ratio of long term autografts reached only 60% of control values. Although fiber hypertrophy suggests that cats use autografted muscles, lower than control succinate dehydrogenase activity may result from altered recruitment.

scholarly journals Endurance training-induced increase in muscle oxidative capacity without loss of muscle mass in younger and older resistance-trained men

2021 ◽  
Author(s):  
Paul William Hendrickse ◽  
Tomas Venckunas ◽  
Justinas Platkevicius ◽  
Ramutis Kairaitis ◽  
Sigitas Kamandulis ◽  
...  
Keyword(s):  
Resistance Training ◽  
Endurance Training ◽  
Muscle Mass ◽  
Oxidative Capacity ◽  
Cross Sectional Area ◽  
Type I ◽  
Sectional Area ◽  
Negative Consequences ◽  
Cross Sectional ◽  
The Impact

AbstractWhile concurrent training is regularly used in older populations, the inverse relationship between fibre size and oxidative capacity suggests that endurance training in resistance-trained individuals may result in some loss of resistance training-induced gains in muscle mass, which may be more pronounced in older people. We investigated the impact of superimposed endurance training in younger (28.5 ± 4.8 years; n = 8) and older (67.5 ± 5.5 years; n = 7) highly resistance-trained men. Participants underwent a 10-week endurance cycling training programme consisting of five 6-min intervals at 75% max heart rate (HRmax) separated by 4-min intervals at 90% HRmax. The anatomical cross-sectional area (ACSA) of the thigh muscles, as determined with MRI, was 24% smaller in older compared to younger participants (p < 0.001). Although maximal oxygen consumption (VO2max) was also lower in the older group (p < 0.001), VO2max per kg body mass did not differ significantly between younger and older participants. Histological analyses of biopsies of the m. vastus lateralis showed that endurance training induced an increase in succinate dehydrogenase activity in both younger and older participants (p ≤ 0.043), and an increase in the number of capillaries around type I fibres (p = 0.017). The superimposed endurance training did not induce a significant decrease in thigh ACSA, fibre cross-sectional area, or knee extensor maximum voluntary isometric force. These observations indicate that adding endurance training to resistance training can lead to positive endurance-related adaptations without negative consequences for muscle size and strength in older and younger resistance-trained people.

Activation-induced reduction of SDH activity in diaphragm muscle fibers

1993 ◽  
Vol 75 (6) ◽  
pp. 2689-2695 ◽  
Author(s):  
B. D. Johnson ◽  
G. C. Sieck
Keyword(s):  
Muscle Fibers ◽  
Processing System ◽  
Oxidative Capacity ◽  
Ringer Solution ◽  
Male Rats ◽  
Diaphragm Muscle ◽  
Type I ◽  
Fiber Types ◽  
Serial Sections ◽  
Glycogen Utilization

In this study, we examined whether exhaustive activation reduces succinate dehydrogenase (SDH) activity in diaphragm muscle fibers. In adult male rats (approximately 300 g), the costal diaphragm was excised and positioned in a chamber perfused with mammalian Ringer solution kept at 26 degrees C and oxygenated with 95% O2–5% CO2. The muscle was stimulated directly at 10 or 75 Hz in trains of 500 ms duration (1/s) for 8 min. An adjacent unstimulated segment of muscle served as control. The two muscle segments were frozen, and serial sections were stained for myofibrillar adenosinetriphosphatase activity after alkaline and acid preincubation to classify type I, IIa, and IIb fibers. The extent of glycogen utilization was also examined histochemically to confirm exhaustive activation of muscle fibers. SDH activity was quantified using a microdensitometric procedure implemented on an image-processing system. Exhaustive activation at both 10 and 75 Hz caused a significant decrease in SDH activity of all fiber types, with the decrease after 10-Hz stimulation being greater than that after 75-Hz stimulation. At both stimulation frequencies, type IIb fibers demonstrated the greatest decrease in SDH activity (36% after 10-Hz and 27% after 75-Hz stimulation), whereas type I and IIa fibers both displayed reductions of approximately 27 and approximately 19% after 10- and 75-Hz stimulation, respectively. The greater reduction of SDH activity in type IIb fibers indicates an inverse relationship between activation-induced reductions in SDH activity and fiber oxidative capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Statistical Analysis of Fiber Area in Human Skeletal Muscle

2002 ◽  
Vol 27 (4) ◽  
pp. 415-422 ◽  
Author(s):  
Michael R.M. Mcguigan ◽  
William J. Kraemer ◽  
Michael R. Deschenes ◽  
Scott E. Gordon ◽  
Takashi Kitaura ◽  
...  
Keyword(s):  
Fiber Type ◽  
Cross Sectional Area ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Area ◽  
Random Block ◽  
Type I Fibers ◽  
Accurate Reflection

Previous research has indicated that 50 fiber measurements per individual for type I and II fibers would be sufficient to characterize the fiber areas. This study replicated the work of McCall et al. (1998) using the three major fiber types (I, IIA, and IIB) and sampling larger populations of fibers. Random blocks of fibers were also examined to investigate how well they correlated with the overall mean average fiber area. Using random blocks of 50 fibers provided an accurate reflection of the type IIB fibers (r = 0.96-0.98) but not for the type I (r = 0.85-0.94) or IIA fibers (r = 0.80-0.91). Type I fibers were consistently reflected by a random block of 150 fibers (r = 0.95-0.98) while type IIA fibers required random blocks of 200 fibers (r = 0.94-0.98), which appeared to provide an accurate reflection of the cross-sectional area. These results indicate that for a needle biopsy different numbers of fibers are needed depending on the fiber type to accurately characterize the mean fiber population. Key words: fiber type, sample size, cross-sectional area, biopsy

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