Differing mechanisms of cold-induced changes in capillary supply in m. tibialis anterior of rats and hamsters

2002 ◽  
Vol 205 (6) ◽  
pp. 829-840 ◽  
Author(s):  
Durmus Deveci ◽  
Stuart Egginton
Keyword(s):  
Skeletal Muscle ◽  
Cold Acclimation ◽  
Oxygen Diffusion ◽  
Tibialis Anterior ◽  
Capillary Density ◽  
Disuse Atrophy ◽  
Diffusion Distance ◽  
Capillary Supply ◽  
Fibre Size ◽  
Anatomical Adaptations

SUMMARY The physiological, metabolic and anatomical adaptations of skeletal muscle to chronic cold exposure were investigated in Wistar rats (Rattus norvegicus), a species that defends core temperature, and Syrian hamsters (Mesocricetus auratus), which may adopt a lower set point under unfavourable conditions. Animals were exposed to a simulated onset of winter in an environmental chamber, progressively shortening photoperiod and reducing temperature from 12 h:12 h L:D and 22°C to 1 h:23 h L:D and 5°C over 4 weeks. The animals were left at 4°C for a further 4 weeks to complete the process of cold-acclimation. M. tibialis anterior from control (euthermic) and cold-acclimated animals of similar mass showed a significant hyperactivity-induced hypertrophy in the rat, but a small disuse atrophy in the hamster. Little evidence was found for interconversion among fibre types in skeletal muscle on cold-acclimation, and only modest differences were seen in activity of oxidative or glycolytic enzymes in either species. However, adjustments in Type II fibre size paralleled the muscle hypertrophy in rat and atrophy in hamster. Cold-induced angiogenesis was present in the rat, averaging a 28 % increase in capillary-to-fibre ratio (C:F) but, as this was balanced by fibre hypertrophy across the whole muscle, there was no change in capillary density (CD). In contrast, the C:F was similar in both groups of hamsters, whereas CD rose by 33 % in line with fibre atrophy. Within distinct regions of the m. tibialis anterior, there was a correlation between angiogenesis and fibre size in rats, in which oxygen diffusion distance increased, but not in hamsters, in which there was a reduced oxygen diffusion distance. Consequently, the change in C:F was greatest (39 %) in the glycolytic cortex region of the m. tibialis anterior in rats. We conclude that non-hibernator and hibernator rodents improve peripheral oxygen transport following cold-acclimation by different mechanisms. In rats, an increase in fibre girth was accompanied by a true angiogenesis, while the improved apparent capillary supply in hamsters was due to smaller fibre diameters. These responses are consistent with the strategies of resisting and accommodating, respectively, an annual fall in environmental temperature.

scholarly journals Is human skeletal muscle capillary supply modelled according to fibre size or fibre type?

1997 ◽  
Vol 82 (1) ◽  
pp. 231-234 ◽  
Author(s):  
SK Ahmed ◽  
S Egginton ◽  
PM Jakeman ◽  
AF Mannion ◽  
HF Ross
Keyword(s):  
Skeletal Muscle ◽  
Fibre Type ◽  
Human Skeletal Muscle ◽  
Capillary Supply ◽  
Fibre Size

Resistance and aerobic training in older men: effects onV˙o 2 peak and the capillary supply to skeletal muscle

1997 ◽  
Vol 82 (4) ◽  
pp. 1305-1310 ◽  
Author(s):  
R. T. Hepple ◽  
S. L. M. Mackinnon ◽  
J. M. Goodman ◽  
S. G. Thomas ◽  
M. J. Plyley
Keyword(s):  
Skeletal Muscle ◽  
Aerobic Training ◽  
Aerobic Power ◽  
Vastus Lateralis ◽  
Older Men ◽  
Capillary Density ◽  
Cycle Ergometer ◽  
Older Population ◽  
Capillary Supply

Hepple, R. T., S. L. M. Mackinnon, J. M. Goodman, S. G. Thomas, and M. J. Plyley. Resistance and aerobic training in older men: effects onV˙o 2 peak and the capillary supply to skeletal muscle. J. Appl. Physiol. 82(4): 1305–1310, 1997.—Both aerobic training (AT) and resistance training (RT) may increase aerobic power (V˙o 2 peak) in the older population; however, the role of changes in the capillary supply in this response has not been evaluated. Twenty healthy men (age 65–74 yr) engaged in either 9 wk of lower body RT followed by 9 wk of AT on a cycle ergometer (RT→AT group) or 18 wk of AT on a cycle ergometer (AT→AT group). RT was performed three times per week and consisted of three sets of four exercises at 6–12 repetitions maximum. AT was performed three times per week for 30 min at 60–70% heart rate reserve.V˙o 2 peak was increased after both RT and AT ( P < 0.05). Biopsies (vastus lateralis) revealed that the number of capillaries per fiber perimeter length was increased after both AT and RT ( P < 0.05), paralleling the changes in V˙o 2 peak, whereas capillary density was increased only after AT ( P < 0.01). These results, and the finding of a significant correlation between the change in capillary supply and V˙o 2 peak( r = 0.52), suggest the possibility that similar mechanisms may be involved in the increase ofV˙o 2 peak after high-intensity RT and AT in the older population.

scholarly journals The Effect of Physical Activity on VEGF and HIF-1 Signaling

2020 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Mehran Ghahramani ◽  
Zeinab Razavi Majd
Keyword(s):  
Physical Activity ◽  
Research Methods ◽  
Oxygen Diffusion ◽  
Capillary Density ◽  
Diffusion Distance ◽  
Exclusion Criteria ◽  
Capacity Increase ◽  
Temporary Decrease

Context: The purpose of the present study was to investigate the context of research into the physiological roles of VEGF and the most important potential mechanisms that may lead to a temporary decrease in serum VEGF, as well as to perform a desirable conclusion and provide more relevant data from previous research. Methods: In this study, articles were searched in specialized databases and 40 related articles were selected based on inclusion and exclusion criteria. Then the effect of physical activity on VEGF and HIF-1 signaling was investigated. Results: Exercise and physical activity by stimulating and activating VEGF and HIF-1 signals may induce generating new arteries and angiogenesis. Conclusions: The present study showed that physical activity increases capillary density by increasing the level of diffusion, increasing the time of exchange between blood and tissue, and decreasing the oxygen diffusion distance. As a result, capillary dilatation and capacity increase and ultimately it improves athletes' performance.

Reduced fibre size, capillary supply and mitochondrial activity in constitutional thinness' skeletal muscle

2018 ◽  
Vol 224 (3) ◽  
pp. e13097 ◽  
Author(s):  
B. Galusca ◽  
J. Verney ◽  
E. Meugnier ◽  
Y. Ling ◽  
P. Edouard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Activity ◽  
Capillary Supply ◽  
Fibre Size

Skeletal and cardiac muscle protein turnover during cold acclimation in young rats

2000 ◽  
Vol 278 (3) ◽  
pp. R705-R711 ◽  
Author(s):  
T. A. McAllister ◽  
J. R. Thompson ◽  
S. E. Samuels
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Cardiac Muscle ◽  
Cold Acclimation ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Muscle Protein Turnover ◽  
Protein Mass ◽  
The Absolute

The effect of long-term cold exposure on skeletal and cardiac muscle protein turnover was investigated in young growing animals. Two groups of 36 male 28-day-old rats were maintained at either 5°C (cold) or 25°C (control). Rates of protein synthesis and degradation were measured in vivo on days 5, 10, 15, and 20. Protein mass by day 20 was ∼28% lower in skeletal muscle (gastrocnemius and soleus) and ∼24% higher in heart in cold compared with control rats ( P < 0.05). In skeletal muscle, the fractional rates of protein synthesis ( k syn) and degradation ( k deg) were not significantly different between cold and control rats, although k syn was lower (approximately −26%) in cold rats on day 5; consequent to the lower protein mass, the absolute rates of protein synthesis (approximately −21%; P < 0.05) and degradation (approximately −13%; P < 0.1) were lower in cold compared with control rats. In heart, overall, k syn(approximately +12%; P < 0.1) and k deg(approximately +22%; P < 0.05) were higher in cold compared with control rats; consequently, the absolute rates of synthesis (approximately +44%) and degradation (approximately +54%) were higher in cold compared with control rats ( P < 0.05). Plasma triiodothyronine concentration was higher ( P < 0.05) in cold compared with control rats. These data indicate that long-term cold acclimation in skeletal muscle is associated with the establishment of a new homeostasis in protein turnover with decreased protein mass and normal fractional rates of protein turnover. In heart, unlike skeletal muscle, rates of protein turnover did not appear to immediately return to normal as increased rates of protein turnover were observed beyond day 5. These data also indicate that increased rates of protein turnover in skeletal muscle are unlikely to contribute to increased metabolic heat production during cold acclimation.

scholarly journals Skeletal muscle PGC-1β signaling is sufficient to drive an endurance exercise phenotype and to counteract components of detraining in mice

2017 ◽  
Vol 312 (5) ◽  
pp. E394-E406 ◽  
Author(s):  
Samuel Lee ◽  
Teresa C. Leone ◽  
Lisa Rogosa ◽  
John Rumsey ◽  
Julio Ayala ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Early Stage ◽  
Peroxisome Proliferator ◽  
Disuse Atrophy ◽  
Proof Of Concept ◽  
Peroxisome Proliferator Activated Receptor ◽  
Muscle Disuse ◽  
Training Response

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α and -1β serve as master transcriptional regulators of muscle mitochondrial functional capacity and are capable of enhancing muscle endurance when overexpressed in mice. We sought to determine whether muscle-specific transgenic overexpression of PGC-1β affects the detraining response following endurance training. First, we established and validated a mouse exercise-training-detraining protocol. Second, using multiple physiological and gene expression end points, we found that PGC-1β overexpression in skeletal muscle of sedentary mice fully recapitulated the training response. Lastly, PGC-1β overexpression during the detraining period resulted in partial prevention of the detraining response. Specifically, an increase in the plateau at which O2 uptake (V̇o2) did not change from baseline with increasing treadmill speed [peak V̇o2 (ΔV̇o2max)] was maintained in trained mice with PGC-1β overexpression in muscle 6 wk after cessation of training. However, other detraining responses, including changes in running performance and in situ half relaxation time (a measure of contractility), were not affected by PGC-1β overexpression. We conclude that while activation of muscle PGC-1β is sufficient to drive the complete endurance phenotype in sedentary mice, it only partially prevents the detraining response following exercise training, suggesting that the process of endurance detraining involves mechanisms beyond the reversal of muscle autonomous mechanisms involved in endurance fitness. In addition, the protocol described here should be useful for assessing early-stage proof-of-concept interventions in preclinical models of muscle disuse atrophy.

scholarly journals Interval and Continuous Exercise Training Produce Similar Increases in Skeletal Muscle and Left Ventricle Microvascular Density in Rats

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Flávio Pereira ◽  
Roger de Moraes ◽  
Eduardo Tibiriçá ◽  
Antonio C. L. Nóbrega
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Left Ventricle ◽  
Body Weight Gain ◽  
Interval Training ◽  
Capillary Density ◽  
Oxidative Capacity ◽  
Constant Load ◽  
Continuous Exercise ◽  
Muscle Ct

Interval training (IT), consisting of alternated periods of high and low intensity exercise, has been proposed as a strategy to induce more marked biological adaptations than continuous exercise training (CT). The purpose of this study was to assess the effects of IT and CT with equivalent total energy expenditure on capillary skeletal and cardiac muscles in rats. Wistar rats ran on a treadmill for 30 min per day with no slope (0%), 4 times/week for 13 weeks. CT has constant load of 70% max; IT has cycles of 90% max for 1 min followed by 1 min at 50% max. CT and IT increased endurance and muscle oxidative capacity and attenuated body weight gain to a similar extent (P>0.05). In addition, CT and IT similarly increased functional capillary density of skeletal muscle (CT:30.6±11.7%; IT:28.7±11.9%) and the capillary-to-fiber ratio in skeletal muscle (CT:28.7±14.4%; IT:40.1±17.2%) and in the left ventricle (CT:57.3±53.1%; IT:54.3±40.5%). In conclusion, at equivalent total work volumes, interval exercise training induced similar functional and structural alterations in the microcirculation of skeletal muscle and myocardium in healthy rats compared to continuous exercise training.

Structure of the cortical cytoskeleton in fibers of postural muscles and cardiomyocytes of mice after 30-day 2-g centrifugation

2015 ◽  
Vol 118 (5) ◽  
pp. 613-623 ◽  
Author(s):  
Irina V. Ogneva ◽  
V. Gnyubkin ◽  
N. Laroche ◽  
M. V. Maximova ◽  
I. M. Larina ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Mechanical Load ◽  
Tibialis Anterior Muscle ◽  
Muscle Fibers ◽  
Control Group ◽  
Negative Effects ◽  
Transverse Stiffness ◽  
G 12 ◽  
Cortical Cytoskeleton

Altered external mechanical loading during spaceflights causes negative effects on muscular and cardiovascular systems. The aim of the study was estimation of the cortical cytoskeleton statement of the skeletal muscle cells and cardiomyocytes. The state of the cortical cytoskeleton in C57BL6J mice soleus, tibialis anterior muscle fibers, and left ventricle cardiomyocytes was investigated after 30-day 2- g centrifugation (“2- g” group) and within 12 h after its completion (“2- g + 12-h” group). We used atomic force microscopy for estimating cell's transverse stiffness, Western blotting for measuring protein content, and RT-PCR for estimating their expression level. The transverse stiffness significantly decreased in cardiomyocytes (by 16%) and increased in skeletal muscles fibers (by 35% for soleus and by 29% for tibialis anterior muscle fibers) in animals of the 2-g group (compared with the control group). For cardiomyocytes, we found that, in the 2- g + 12-h group, α-actinin-1 content decreased in the membranous fraction (by 27%) and increased in cytoplasmic fraction (by 28%) of proteins (compared with the levels in the 2- g group). But for skeletal muscle fibers, similar changes were noted for α-actinin-4, but not for α-actinin-1. In conclusion, we showed that the different isoforms of α-actinins dissociate from cortical cytoskeleton under increased/decreased of mechanical load.

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