Distribution of myogenic progenitor cells and myonuclei is altered in women with vs. those without chronically painful trapezius muscle

2010 ◽  
Vol 109 (6) ◽  
pp. 1920-1929 ◽  
Author(s):  
Abigail L. Mackey ◽  
Lars L. Andersen ◽  
Ulrik Frandsen ◽  
Charlotte Suetta ◽  
Gisela Sjøgaard
Keyword(s):  
Cross Sections ◽  
Trapezius Muscle ◽  
Motor Units ◽  
Type I ◽  
Trapezius Myalgia ◽  
Low Threshold ◽  
Myogenic Progenitor Cells ◽  
Type I Fibers ◽  
Muscle Biopsies ◽  
Type Ii Fibers

It is hypothesized that repeated recruitment of low-threshold motor units is an underlying cause of chronic pain in trapezius myalgia. This study investigated the distribution of satellite cells (SCs), myonuclei, and macrophages in muscle biopsies from the trapezius muscle of 42 women performing repetitive manual work, diagnosed with trapezius myalgia (MYA; 44 ± 8 yr; mean ± SD) and 20 matched healthy controls (CON; 45 ± 9 yr). Our hypothesis was that muscle of MYA, in particular type I fibers, would demonstrate higher numbers of SCs, myonuclei, and macrophages compared with CON. SCs were identified on muscle cross sections by combined immunohistochemical staining for Pax7, type I myosin, and laminin, allowing the number of SCs associated with type I and II fibers to be determined. We observed a pattern of SC distribution in MYA previously only reported for individuals above 70 yr of age. Compared with CON, MYA demonstrated 19% more SCs per fiber associated with type I fibers (MYA 0.098 ± 0.039 vs. CON 0.079 ± 0.031; P < 0.05) and 40% fewer SCs associated with type II fibers (MYA 0.047 ± 0.017 vs. CON 0.066 ± 0.035; P < 0.05). The finding of similar numbers of macrophages between the two groups was not in line with our hypothesis and suggests that the elevated SC content of MYA was not due to heightened inflammatory cell contents, but rather to provide new myonuclei. The findings of greater numbers of SCs in type I fibers of muscle subjected to repeated low-intensity work support our hypothesis and provide new insight into stimuli capable of regulating SC content.

scholarly journals Axon typing of rat muscle nerves using a double staining procedure for cholinesterase and carbonic anhydrase.

1991 ◽  
Vol 39 (12) ◽  
pp. 1617-1625 ◽  
Author(s):  
M J Szabolcs ◽  
A Windisch ◽  
R Koller ◽  
M Pensch
Keyword(s):  
Carbonic Anhydrase ◽  
Cross Sections ◽  
Sensory Nerve ◽  
Histological Section ◽  
Trapezius Muscle ◽  
Motor Units ◽  
Conventional Technique ◽  
Nerve Fibers ◽  
Staining Procedure ◽  
Muscle Nerve

We developed a method for detecting activity of axonal cholinesterase (CE) and carbonic anhydrase (CA)--markers for motor and sensory nerve fibers (NFs)--in the same histological section. To reach this goal, cross-sections of muscle nerves were sequentially incubated with the standard protocols for CE and CA histochemistry. A modified incubation medium was used for CA in which Co++ is replaced by Ni++. This avoids interference of the two histochemical reactions because Co++ binds unspecifically to the brown copper-ferroferricyanide complex representing CE activity, whereas Ni++ does not. Cross-sections of the trapezius muscle nerve containing efferent and afferent NFs in segregated fascicles showed that CE activity was confined to motor NFs. Axonal CA was detected solely in sensory NFs. The number of labeled motor and sensory NFs determined in serial cross-sections stained with either the new or the conventional technique was not significantly different. Morphometric analysis revealed that small unreactive NFs (diameter less than 5 microns) are afferent, medium-sized ones (5 microns less than d less than 7 microns) are unclassifiable, and large ones (d greater than 7 microns) are efferent. The heterogenous CE activity of thick (alpha) motor NFs is linked to the type of their motor units. "Fast" motor units contain CE reactive NFs; "slow" ones have CE negative neurites.

Relative efficacy of slow and fast alpha-motoneurons to reinnervate mouse soleus muscle

1990 ◽  
Vol 258 (1) ◽  
pp. C62-C70 ◽  
Author(s):  
G. Desypris ◽  
D. J. Parry
Keyword(s):  
Soleus Muscle ◽  
Motor Units ◽  
Type I ◽  
Hybrid Fibers ◽  
Muscle Area ◽  
Time To Peak ◽  
Control Units ◽  
Mean Size ◽  
Type I Fibers ◽  
Whole Muscle

Contractile and histochemical properties of reinnervated motor units in soleus muscles of C57BL/6J mice were examined 1 mo after sectioning the soleus nerve. Fifty-one motor units were isolated by the technique of ventral root splitting. Their sizes ranged from 0.4 to 13.6% of whole muscle tetanic tension (Po) with a mean size of 5.3% Po corresponding to 19 motor units. In control unoperated mice, the range was 2.2-8.6% Po, with a mean size of 4.8% Po corresponding to 22 motor units. Although no clear relationship between unit time to peak tension and size was seen in control units, it appeared that in the reinnervated muscle the large units were also slow contracting, whereas the smaller units were predominantly fast contracting. Adenosinetriphosphatase (ATPase) staining revealed an increase in the proportion of muscle area occupied by type I fibers in reinnervated soleus compared with control soleus. Immunohistochemical staining of reinnervated soleus with monoclonal antibodies against type I and IIa myosin showed the presence of hybrid fibers containing both myosins. It is concluded that during reinnervation most motoneurons reinnervate the soleus muscle of the mouse. The hypothesis that slow motoneurons are more adept at expanding their innervating field than fast motoneurons is also supported by the data.

Diaphragm muscle fatigue resistance during postnatal development

1991 ◽  
Vol 71 (2) ◽  
pp. 458-464 ◽  
Author(s):  
G. C. Sieck ◽  
M. Fournier ◽  
C. E. Blanco
Keyword(s):  
Postnatal Development ◽  
Fatigue Resistance ◽  
Muscle Fibers ◽  
Diaphragm Muscle ◽  
Fatigue Properties ◽  
Type I ◽  
Type Ii ◽  
Cross Sectional ◽  
Type I Fibers ◽  
Type Ii Fibers

postnatal development. Both twitch contraction time and half-relaxation time decreased progressively with age. Correspondingly, the force-frequency curve was shifted to the left early in development compared with adults. The ratio of peak twitch force to maximum tetanic force decreased with age. Fatigue resistance of the diaphragm was highest at birth and then progressively decreased with age. At birth, most diaphragm muscle fibers stained darkly for myofibrillar adenosinetriphosphatase after alkaline preincubation and thus would be classified histochemically as type II. During subsequent postnatal development, the proportion of type I fibers (lightly stained for adenosinetriphosphatase) increased while the number of type II fibers declined. At birth, type I fibers were larger than type II fibers. The size of both fiber types increased with age, but the increase in cross-sectional area was greater for type II fibers. On the basis of fiber type proportions and mean cross-sectional areas, type I fibers contributed 15% of total muscle mass at birth and 25% in adults. Thus postnatal changes in diaphragm contractile and fatigue properties cannot be attributed to changes in the relative contribution of histochemically classified type I and II fibers. However, the possibility that these developmental changes in diaphragm contractile and fatigue properties correlated with the varying contractile protein composition of muscle fibers was discussed.

Energy metabolism in single human muscle fibers during contraction without and with epinephrine infusion

1991 ◽  
Vol 260 (5) ◽  
pp. E713-E718 ◽  
Author(s):  
P. L. Greenhaff ◽  
J. M. Ren ◽  
K. Soderlund ◽  
E. Hultman
Keyword(s):  
Electrical Stimulation ◽  
Muscle Fibers ◽  
Type I ◽  
Type Ii ◽  
Short Term ◽  
Epinephrine Infusion ◽  
Before And After ◽  
Type I Fibers ◽  
Type Ii Fibers ◽  
Femoris Muscle

The concentrations of glycogen, ATP, and phosphocreatine were analyzed in types I and II muscle fibers separated from biopsy samples of the quadriceps femoris muscle in five healthy volunteers. Muscle samples were obtained before and after 64 s of intermittent electrical stimulation. The experiment was carried out without and with epinephrine (Epi) infusion. Before stimulation the glycogen concentration was 11% higher in type II than in type I fibers (P less than 0.05). During electrical stimulation, rapid glycogenolysis occurred in type II fibers with hardly any detectable glycogenolysis in type I fibers. The calculated rates of glycogenolysis were 0.18 +/- 0.14 and 3.54 +/- 0.53 mmol glucose.kg dry muscle-1.s-1 in types I and II fibers, respectively. Epi infusion increased the rate of glycogenolysis during electrical stimulation in type I fibers (10-fold) but did not enhance the rate in type II fibers (P greater than 0.05). It is considered that, during short-term maximal muscle contraction, rapid muscle glycogenolysis occurs predominantly in type II fibers even though types I and II fibers are recruited and that, when Epi stimulation of glycogenolysis occurs, this is predominantly limited to type I fibers.

Recruitment of single muscle fibers during submaximal cycling exercise

2007 ◽  
Vol 103 (5) ◽  
pp. 1752-1756 ◽  
Author(s):  
T. M. Altenburg ◽  
H. Degens ◽  
W. van Mechelen ◽  
A. J. Sargeant ◽  
A. de Haan
Keyword(s):  
Cross Sections ◽  
Vastus Lateralis ◽  
Periodic Acid ◽  
Ratio Method ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Type Ii ◽  
Periodic Acid Schiff ◽  
Cycling Exercise ◽  
Type Ii Fibers

In literature, an inconsistency exists in the submaximal exercise intensity at which type II fibers are activated. In the present study, the recruitment of type I and II fibers was investigated from the very beginning and throughout a 45-min cycle exercise at 75% of the maximal oxygen uptake, which corresponded to 38% of the maximal dynamic muscle force. Biopsies of the vastus lateralis muscle were taken from six subjects at rest and during the exercise, two at each time point. From the first biopsy single fibers were isolated and characterized as type I and II, and phosphocreatine-to-creatine (PCr/Cr) ratios and periodic acid-Schiff (PAS) stain intensities were measured. Cross sections were cut from the second biopsy, individual fibers were characterized as type I and II, and PAS stain intensities were measured. A decline in PCr/Cr ratio and in PAS stain intensity was used as indication of fiber recruitment. Within 1 min of exercise both type I and, although to a lesser extent, type II fibers were recruited. Furthermore, the PCr/Cr ratio revealed that the same proportion of fibers was recruited during the whole 45 min of exercise, indicating a rather constant recruitment. The PAS staining, however, proved inadequate to fully demonstrate fiber recruitment even after 45 min of exercise. We conclude that during cycling exercise a greater proportion of type II fibers is recruited than previously reported for isometric contractions, probably because of the dynamic character of the exercise. Furthermore, the PCr/Cr ratio method is more sensitive in determining fiber activation than the PAS stain intensity method.

scholarly journals Denervation and reinnervation of fast and slow muscles. A histochemical study in rats.

1975 ◽  
Vol 23 (11) ◽  
pp. 808-827 ◽  
Author(s):  
M M Jaweed ◽  
G J Herbison ◽  
J F Ditunno
Keyword(s):  
Fiber Diameter ◽  
Histochemical Study ◽  
Fiber Type ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Type I Fibers ◽  
Type Ii Fibers ◽  
Fast Muscles ◽  
Slow And Fast Muscles

A histochemical study, using myosin-adenosine triphosphatase activity at pH 9.4, was conducted in soleus and plantaris muscles of adult rats, after bilateral crushing of the sciatic nerve at the sciatic notch. The changes in fiber diameter and per cent composition of type I and type II fibers plus muscle weights were evaluated along the course of denervation-reinnervation curve at 1, 2, 3, 4 and 6 weeks postnerve crush. The study revealed that in the early denervation phase (up to 2 weeks postcrush) both the slow and fast muscles, soleus and plantaris, resepctively, atrophied similarly in muscle mass. Soleus increased in the number of type II fibers, which may be attributed to "disuse" effect. During the same period, the type I fibers of soleus atrophied as much or slightly more than the type II fibers; whereas the type II fibers of plantaris atrophied significantly more than the type I fibers, reflecting that the process of denervation, in its early stages, may affect the two fiber types differentially in the slow and fast muscles. It was deduced that the type I fibers of plantaris may be essentially different in the slow (soleus) and fast (plantaris) muscles under study. The onset of reinnervation, as determined by the increase in muscle weight and fiber diameter of the major fiber type, occurred in soleus and plantaris at 2 and 3 weeks postcrush, respectively, which confirms the earlier hypotheses that the slow muscles are reinnervated sooner than the fast muscles. It is suggested that the reinnervation of muscle after crush injury may be specific to the muscle type or its predominant fiber type.

Peripheral Nerve Findings in Rett Syndrome

1988 ◽  
Vol 3 (1_suppl) ◽  
pp. S25-S30 ◽  
Author(s):  
Richard H. Haas ◽  
Seth Love
Keyword(s):  
Rett Syndrome ◽  
Sural Nerve ◽  
Enzyme Histochemistry ◽  
Axonal Neuropathy ◽  
Type I ◽  
Normal Density ◽  
Hirano Bodies ◽  
Peroneus Brevis ◽  
Type I Fibers ◽  
Muscle Biopsies

Sural nerve and peroneus brevis muscle biopsies were studied in 12 patients with Rett syndrome, ten with the typical form of the disorder according to 1985 criteria, and two with atypical features. Ages ranged from 23 months to 25 years. All stages of the disease were represented. There was evidence of a mild axonal neuropathy in seven of 12 patients. Degenerative and occasional regenerative changes were seen in five sural nerve biopsies, including one from the youngest patient in the series, who was normally nourished and fully ambulatory. Occasional nonspecific ultrastructural abnormalities were present, including accumulation of pi granules in Schwann cells and Hirano bodies within axons. However, morphometric analysis of the four nerves in which these alterations were most prominent showed a normal density and size distribution of myelinated fibers. Enzyme histochemistry of the peroneus brevis biopsies demonstrated abnormal predominance of type II muscle fibers in three of the 12 biopsies and atrophy of type I fibers in one patient. (J Child Neurol 1988;3(Suppl):S25-S30).

scholarly journals Functional and structural adaptations of skeletal muscle to microgravity

2001 ◽  
Vol 204 (18) ◽  
pp. 3201-3208 ◽  
Author(s):  
Robert H. Fitts ◽  
Danny R. Riley ◽  
Jeffrey J. Widrick
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Peak Force ◽  
Type I ◽  
Type Ii ◽  
Shortening Velocity ◽  
Slow Type ◽  
Fiber Atrophy ◽  
Type I Fibers ◽  
Type Ii Fibers

SUMMARY Our purpose is to summarize the major effects of space travel on skeletal muscle with particular emphasis on factors that alter function. The primary deleterious changes are muscle atrophy and the associated decline in peak force and power. Studies on both rats and humans demonstrate a rapid loss of cell mass with microgravity. In rats, a reduction in muscle mass of up to 37% was observed within 1 week. For both species, the antigravity soleus muscle showed greater atrophy than the fast-twitch gastrocnemius. However, in the rat, the slow type I fibers atrophied more than the fast type II fibers, while in humans, the fast type II fibers were at least as susceptible to space-induced atrophy as the slow fiber type. Space flight also resulted in a significant decline in peak force. For example, the maximal voluntary contraction of the human plantar flexor muscles declined by 20–48% following 6 months in space, while a 21% decline in the peak force of the soleus type I fibers was observed after a 17-day shuttle flight. The reduced force can be attributed both to muscle atrophy and to a selective loss of contractile protein. The former was the primary cause because, when force was expressed per cross-sectional area (kNm−2), the human fast type II and slow type I fibers of the soleus showed no change and a 4% decrease in force, respectively. Microgravity has been shown to increase the shortening velocity of the plantar flexors. This increase can be attributed both to an elevated maximal shortening velocity (V0) of the individual slow and fast fibers and to an increased expression of fibers containing fast myosin. Although the cause of the former is unknown, it might result from the selective loss of the thin filament actin and an associated decline in the internal drag during cross-bridge cycling. Despite the increase in fiber V0, peak power of the slow type I fiber was reduced following space flight. The decreased power was a direct result of the reduced force caused by the fiber atrophy. In addition to fiber atrophy and the loss of force and power, weightlessness reduces the ability of the slow soleus to oxidize fats and increases the utilization of muscle glycogen, at least in rats. This substrate change leads to an increased rate of fatigue. Finally, with return to the 1g environment of earth, rat studies have shown an increased occurrence of eccentric contraction-induced fiber damage. The damage occurs with re-loading and not in-flight, but the etiology has not been established.

Fiber type and temperature dependence of inorganic phosphate: implications for fatigue

2004 ◽  
Vol 287 (3) ◽  
pp. C673-C681 ◽  
Author(s):  
E. P. Debold ◽  
H. Dave ◽  
R. H. Fitts
Keyword(s):  
Contractile Function ◽  
Contractile Activity ◽  
Isometric Force ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Shortening Velocity ◽  
Single Fibers ◽  
Type I Fibers ◽  
Type Ii Fibers

Elevated levels of Pi are thought to cause a substantial proportion of the loss in muscular force and power output during fatigue from intense contractile activity. However, support for this hypothesis is based, in part, on data from skinned single fibers obtained at low temperatures (≤15°C). The effect of high (30 mM) Pi concentration on the contractile function of chemically skinned single fibers was examined at both low (15°C) and high (30°C) temperatures using fibers isolated from rat soleus (type I fibers) and gastrocnemius (type II fibers) muscles. Elevating Pi from 0 to 30 mM at saturating free Ca2+ levels depressed maximum isometric force (Po) by 54% at 15°C and by 19% at 30°C ( P < 0.05; significant interaction) in type I fibers. Similarly, the Po of type II fibers was significantly more sensitive to high levels of Pi at the lower (50% decrease) vs. higher temperature (5% decrease). The maximal shortening velocity of both type I and type II fibers was not significantly affected by elevated Pi at either temperature. However, peak fiber power was depressed by 49% at 15°C but by only 16% at 30°C in type I fibers. Similarly, in type II fibers, peak power was depressed by 40 and 18% at 15 and 30°C, respectively. These data suggest that near physiological temperatures and at saturating levels of intracellular Ca2+, elevated levels of Pi contribute less to fatigue than might be inferred from data obtained at lower temperatures.

Motor Control of Low-Threshold Motor Units in the Human Trapezius Muscle

2001 ◽  
Vol 85 (4) ◽  
pp. 1777-1781 ◽  
Author(s):  
R. H. Westgaard ◽  
C. J. De Luca
Keyword(s):  
Firing Rate ◽  
Contractile Activity ◽  
Trapezius Muscle ◽  
Motor Units ◽  
Computer Algorithms ◽  
Firing Rates ◽  
Emg Signal ◽  
Onion Skin ◽  
Active Motor ◽  
Low Threshold

The firing pattern of low-threshold motor units was examined in the human trapezius and first dorsal interosseous (FDI) muscles during slowly augmenting, low-amplitude contractions that were intended to mimic contractile activity in postural muscles. The motor unit activity was detected with a special needle electrode and was analyzed with the assistance of computer algorithms. The surface electromyographic (EMG) signal was recorded. Its root-mean-square (RMS) value was calculated and presented to the subject who used it to regulate the muscle force level. In the trapezius, there was minimal, if any, firing rate modulation of early recruited motor units during slow contractions (≤1% EMGmax/s), and later recruited motor units consistently presented higher peak firing rates. As the force rate of the contraction increased (3% EMGmax/s), the firing rates of the motor units in the trapezius approached an orderly hierarchical pattern with the earliest recruited motor units having the greatest firing rate. In contrast, and as reported previously, the firing rates of all motor units in the FDI always presented the previously reported hierarchical “onion-skin” pattern. We conclude that the low-threshold motor units in the postural trapezius muscle, that is the motor units that are most often called on to activate the muscle in postural activities, have different control features in slow and fast contractions. More detailed analysis revealed that, in the low force-rate contractions of the trapezius, recruitment of new motor units inhibited the firing rate of active motor units, providing an explanation for the depressed firing rate of the low-threshold motor units. We speculate that Renshaw cell inhibition contributes to the observed deviation of the low-threshold motor units from the hierarchical onion-skin pattern.

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