scholarly journals Passive repetitive stretching is associated with greater muscle mass and cross-sectional area in the sarcopenic muscle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yumin Wang ◽  
Satoshi Ikeda ◽  
Katsunori Ikoma
Keyword(s):  
Muscle Mass ◽  
Gastrocnemius Muscle ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Passive Stretching

AbstractMechanical stimulation has benefits for muscle mass and function. Passive stretching is widely performed in clinical rehabilitation medicine. However, the hypertrophic effects of passive repetitive stretching on senescent skeletal muscles against muscle atrophy remain unknown. We used senescence-accelerated model SAM-P8 mice. The gastrocnemius muscle was passively repetitive stretched by manual ankle dorsiflexion for 15 min, 5 days a week for 2 weeks under deep anesthesia. We examined the effects of passive stretching on muscle mass, myofiber cross-sectional area, muscle fiber type composition, satellite cell and myonuclei content, signaling pathways involved in muscle protein synthesis, and myogenic regulatory factors. The gastrocnemius muscle weight and fiber cross-sectional area of the stretched side was found greater compared with that of the unstretched side. Passive repetitive stretching increased the mRNA expression level of Akt, p70S6K, 4E-BP1, Myf5, myogenin, MuRF1.The phosphorylation level of p70S6K significantly increased in the stretched muscles, whereas of Akt and 4E-BP1 remained unchanged, compared to the unstretched side. The Pax7+ cells and myonuclei content did not differ between the stretched and unstretched muscles. These findings suggest that the hypertrophic or suppressed atrophic observation in the stretched muscles are mainly attributable to the protein turnover provoked by stretching. These findings are applicable to clinical muscle strengthening and sarcopenia prevention.

scholarly journals Passive repetitive stretching increases skeletal muscle mass and myofiber cross-sectional area in senescence-accelerated model mouse

2021 ◽  
Author(s):  
Yumin Wang ◽  
Satoshi Ikeda ◽  
Katsunori Ikoma
Keyword(s):  
Skeletal Muscle ◽  
Mrna Expression ◽  
Signaling Pathways ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Gastrocnemius Muscle ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Passive Stretching

Abstract Mechanical stimulation has benefits for muscle mass and function. Passive stretching is widely performed in clinical rehabilitation medicine. However, the hypertrophic effects of passive repetitive stretching on senescent skeletal muscles against muscle atrophy remain unknown. We used senescence-accelerated model SAM-P8 mice. The gastrocnemius muscle was passively repetitive stretched by manual ankle dorsiflexion for 15 min, 5 days a week for 2 weeks under deep anesthesia. We examined the effects of passive stretching on muscle mass, myofiber cross-sectional area, muscle fiber type and composition, satellite cell content, mRNA expression of the signaling pathways involved in muscle protein synthesis, muscle-specific ubiquitin ligases, and myogenic regulatory factors. The gastrocnemius muscle weight of the stretched side increased compared with that of the unstretched side. In addition to the increase in muscle mass, muscle fiber cross-sectional area of the stretched side was greater than that of the unstretched side. Passive repetitive stretching significantly increased the mRNA expression level of Akt, p70S6K, 4E-BP1, Myf5, myogenin, MuRF1. Passive repetitive stretching promoted skeletal muscle mass and myofiber cross-sectional area in SAM-P8 mice. These hypertrophic observations are attributable to the stretch-activated signaling pathways involved in protein turnover. These findings are applicable to clinical muscle strengthening and sarcopenia prevention.

Effect of Early Low-Intensity Exercise on Rat Hind-Limb Muscles Following Acute Ischemic Stroke

2006 ◽  
Vol 7 (3) ◽  
pp. 163-174 ◽  
Author(s):  
Myoung-Ae Choe ◽  
Gyeong Ju An ◽  
Yoon-Kyong Lee ◽  
Ji Hye Im ◽  
Smi Choi-Kwon ◽  
...  
Keyword(s):  
Hind Limb ◽  
Gastrocnemius Muscle ◽  
Exercise Group ◽  
Cross Sectional Area ◽  
Type I ◽  
Sectional Area ◽  
Muscle Type ◽  
Cross Sectional ◽  
Low Intensity ◽  
Low Intensity Exercise

This study examined the effects of daily low-intensity exercise following acute stroke on mass, Type I and II fiber cross-sectional area, and myofibrillar protein content of hind-limb muscles in a rat model. Adult male Sprague-Dawley rats were randomly assigned to 1 of 4 groups (n = 7-9 per group): stroke (occlusion of the right middle cerebral artery [RMCA]), control (sham RMCA procedure), exercise, and stroke-exercise. Beginning 48 hours post-stroke induction/sham operation, rats in the exercise group had 6 sessions of exercise in which they ran on a treadmill at grade 10 for 20 min/day at 10 m/min. At 8 days poststroke, all rats were anesthetized and soleus, plantaris, and gastrocnemius muscles were dissected from both the affected and unaffected sides. After 6 sessions of exercise following acute ischemic stroke, the stroke-exercise group showed the following significant (p < .05) increases compared to the stroke-only group: body weight and dietary intake, muscle weight of affected soleus and both affected and unaffected gastrocnemius muscle, Type I fiber cross-sectional area of affected soleus and both affected and unaffected gastrocnemius muscle, Type II fiber cross-sectional area of the unaffected soleus, both affected and unaffected plantaris and gastrocnemius muscle, Type II fiber distribution of affected gastrocnemius muscle, and myofibrillar protein content of both affected and unaffected soleus muscle. Daily low-intensity exercise following acute stroke attenuates hind-limb muscle atrophy in both affected and unaffected sides. The effects of exercise are more pronounced in the soleus and gastrocnemius as compared to the plantaris muscle.

scholarly journals Early life undernutrition in rats

1982 ◽  
Vol 47 (3) ◽  
pp. 417-431 ◽  
Author(s):  
K. S. Bedi ◽  
A. R. Birzgalis ◽  
M. Mahon ◽  
J. L. Smart ◽  
A. C. Wareham
Keyword(s):  
Body Weight ◽  
Relative Frequency ◽  
Cross Sectional Area ◽  
Fibre Types ◽  
Male Rats ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Volume Proportion ◽  
Fibre Number

1. Male rats were undernourished either during the geslational and suckling periods or for a period of time immediately following weaning. Some rats were killed at the end of the period of undernutrition; others were nutritionally rehabilitated for lengthy periods of time before examination. Two muscles, the extensor digitorum longus (EDL) and soleus (SOL) were studied from each rat. Histochemically-stained transverse sections of these muscles were used to determine total number of fibres, the fibre cross-sectional areas and the relative frequency of the various fibre types.2. All rats killed immediately following undernutrition showed significant deficit sin body-weight, muscle weight and fibre cross-sectional area compared to age-matched controls.3. Animals undernourished during gestation and suckling and then fed normally for 5 months showed persistent and significant deficits in body-weight, muscle weight and total fibre number. There were also significant deficits in mean fibre cross-sectional area of each fibre type except for red fibres in the EDL. No difference in the volume proportion of connective tissue was found.4. Rats undernourished after weaning and then fed ad lib. for approximately 7 months had normal body-and muscle weights. Their muscles showed no significant differences in total fibre number, relative frequency of the various fibre types, fibre size or volume proportion of connective lissue.5. These results indicate that, although the effects on rat skeletal muscle of a period of undernutrition after weaning can be rectified, undernutrition before weaning causes lasting deficits.

Regulation of fiber size, oxidative potential, and capillarization in human muscle by resistance exercise

1999 ◽  
Vol 276 (2) ◽  
pp. R591-R596 ◽  
Author(s):  
H. Green ◽  
C. Goreham ◽  
J. Ouyang ◽  
M. Ball-Burnett ◽  
D. Ranney
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Quadriceps Muscle ◽  
Cellular Tissue ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Oxidative Potential ◽  
Cross Sectional

To examine the hypothesis that increases in fiber cross-sectional area mediated by high-resistance training (HRT) would result in a decrease in fiber capillarization and oxidative potential, regardless of fiber type, we studied six untrained males (maximum oxygen consumption, 45.6 ± 2.3 ml ⋅ kg−1 ⋅ min−1; mean ± SE) participating in a 12-wk program designed to produce a progressive hypertrophy of the quadriceps muscle. The training sessions, which were conducted 3 times/wk, consisted of three sets of three exercises, each performed for 6–8 repetitions maximum (RM). Measurements of fiber-type distribution obtained from tissue extracted from the vastus lateralis at 0, 4, 7, and 12 wk indicated reductions ( P < 0.05) in type IIB fibers (15.1 ± 2.1% vs. 7.2 ± 1.3%) by 4 wk in the absence of changes in the other fiber types (types I, IIA, and IIAB). Training culminated in a 17% increase ( P < 0.05) in cross-sectional area by 12 wk with initial increases observed at 4 wk. The increase was independent of fiber type-specific changes. The number of capillaries in contact with each fiber type increased by 12 wk, whereas capillary contacts-to-fiber area ratios remained unchanged. In a defined cross-sectional field, HRT also increased the capillaries per fiber at 12 wk. Training failed to alter cellular oxidative potential, as measured by succinic dehydrogenase (SDH) activity, regardless of fiber type and training duration. It is concluded that modest hypertrophy induced by HRT does not compromise cellular tissue capillarization and oxidative potential regardless of fiber type.

scholarly journals The Nonlinear Relationship Between Psoas Cross-sectional Area and BMI: A New Observation and Its Insights into Diabetes Remission After Roux-en-Y Gastric Bypass

2021 ◽  
Author(s):  
Shaobo Li ◽  
Haoyong Yu ◽  
Pin Zhang ◽  
Yinfang Tu ◽  
Yunfeng Xiao ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Linear Relationship ◽  
Muscle Mass ◽  
Diabetes Remission ◽  
Cross Sectional Area ◽  
Fat Free Mass ◽  
Sectional Area ◽  
Cross Sectional ◽  
Non Linear ◽  
Design And Methods

OBJECTIVE <p>To<a> explore the potential relevance of muscle mass as a variable contributor to body mass index (BMI) on BMI limitations in predicting diabetes remission (DR) after Roux-en-Y gastric bypass (RYGB). </a></p> <p> </p> <p>RESEARCH DESIGN AND METHODS</p> <p>We evaluated the relationship between muscle mass and BMI in 501 patients with type 2 diabetes mellitus and overweight or obesity. Of which <a>186 patients who underwent R</a>YGB were <a>studied to determine the role of baseline muscle mass </a><a>and BMI </a>in predicting DR. Muscle mass was assessed by estimated fat-free mass index (eFFMI) and psoas cross-sectional area (CSA).</p> <p> </p> <p>RESULTS</p> <p>A non-linear relationship existed between psoas CSA and BMI, whereas psoas CSA showed a highly positive correlation with <a>eFFMI</a>. Baseline psoas CSA and eFFMI were better than BMI for predicting 1- and 5-year DR. </p> <p> </p> <p>CONCLUSIONS</p> <p><a>The </a><a>non-linear relationship between</a> muscle mass and BMI may <a>partially contribute to </a><a>BMI limitations in predicting DR</a> after RYGB. </p>

Maintenance of myonuclear domain size in rat soleus after overload and growth hormone/IGF-I treatment

1998 ◽  
Vol 84 (4) ◽  
pp. 1407-1412 ◽  
Author(s):  
G. E. McCall ◽  
D. L. Allen ◽  
J. K. Linderman ◽  
R. E. Grindeland ◽  
R. R. Roy ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Domain Size ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Igf I ◽  
Myonuclear Domain ◽  
The Difference ◽  
Saline Vehicle

The purpose of this study was to determine the effects of functional overload (FO) combined with growth hormone/insulin-like growth factor I (GH/IGF-I) administration on myonuclear number and domain size in rat soleus muscle fibers. Adult female rats underwent bilateral ablation of the plantaris and gastrocnemius muscles and, after 7 days of recovery, were injected three times daily for 14 days with GH/IGF-I (1 mg/kg each; FO + GH/IGF-I group) or saline vehicle (FO group). Intact rats receiving saline vehicle served as controls (Con group). Muscle wet weight was 32% greater in the FO than in the Con group: 162 ± 8 vs. 123 ± 16 mg. Muscle weight in the FO + GH/IGF-I group (196 ± 14 mg) was 59 and 21% larger than in the Con and FO groups, respectively. Mean soleus fiber cross-sectional area of the FO + GH/IGF-I group (2,826 ± 445 μm2) was increased compared with the Con (2,044 ± 108 μm2) and FO (2,267 ± 301 μm2) groups. The difference in fiber size between the FO and Con groups was not significant. Mean myonuclear number increased in FO (187 ± 15 myonuclei/mm) and FO + GH/IGF-I (217 ± 23 myonuclei/mm) rats compared with Con (155 ± 12 myonuclei/mm) rats, although the difference between FO and FO + GH/IGF-I animals was not significant. The mean cytoplasmic volume per myonucleus (myonuclear domain) was similar across groups. These results demonstrate that the larger mean muscle weight and fiber cross-sectional area occurred when FO was combined with GH/IGF-I administration and that myonuclear number increased concomitantly with fiber volume. Thus there appears to be some mechanism(s) that maintains the myonuclear domain when a fiber hypertrophies.

Effects of sprint cycle training on human skeletal muscle

1994 ◽  
Vol 77 (5) ◽  
pp. 2385-2390 ◽  
Author(s):  
C. A. Allemeier ◽  
A. C. Fry ◽  
P. Johnson ◽  
R. S. Hikida ◽  
F. C. Hagerman ◽  
...  
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Cross Sectional Area ◽  
Aerobic Performance ◽  
Vastus Lateralis Muscle ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Fiber ◽  
Cycle Training ◽  
Exercise Induced

Eleven men sprint trained two to three times per week for 6 wk to investigate possible exercise-induced slow-to-fast fiber type conversions. Six individuals served as controls. Both groups were tested at the beginning and end of the study to determine anaerobic performance and maximal oxygen consumption. In addition, pre- and postbiopsies were extracted from the vastus lateralis muscle and were analyzed for fiber type composition, cross-sectional area, and myosin heavy chain (MHC) content. No significant changes were found in anaerobic or aerobic performance variables for either group. Although a trend was found for a decrease in the percentage of type IIb fibers, high-intensity sprint cycle training caused no significant changes in the fiber type distribution or cross-sectional area. However, the training protocol did result in a significant decrease in MHC IIb with a concomitant increase in MHC IIa for the training men. These data appear to support previous investigations that have suggested exercise-induced adaptations within the fast fiber population (IIb-->IIa) after various types of training (endurance and strength).

scholarly journals Inorganic Arsenic Exposure Decreases Muscle Mass and Enhances Denervation-Induced Muscle Atrophy in Mice

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3057
Author(s):  
Chang-Mu Chen ◽  
Min-Ni Chung ◽  
Chen-Yuan Chiu ◽  
Shing-Hwa Liu ◽  
Kuo-Cheng Lan
Keyword(s):  
Drinking Water ◽  
Protein Expression ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Arsenic Exposure ◽  
Inorganic Arsenic ◽  
Cross Sectional Area ◽  
Muscle Endurance ◽  
Sectional Area ◽  
Cross Sectional

Arsenic is a toxic metalloid. Infants with a low birth-weight have been observed in areas with high-level arsenic in drinking water ranging from 463 to 1025 μg/L. A distal muscular atrophy side effect has been observed in acute promyelocytic leukemia patients treated with arsenic trioxide (As2O3) for therapy. The potential of As2O3 on muscle atrophy remains to be clarified. In this study, the myoatrophic effect of arsenic was evaluated in normal mice and sciatic nerve denervated mice exposed with or without As2O3 (0.05 and 0.5 ppm) in drinking water for 4 weeks. We found that both 0.05 and 0.5 ppm As2O3 increased the fasting plasma glucose level; but only 0.5 ppm arsenic exposure significantly decreased muscle mass, muscle endurance, and cross-sectional area of muscle fibers, and increased muscle Atrogin-1 protein expression in the normal mice. Both 0.05 and 0.5 ppm As2O3 also significantly enhanced the inhibitory effects on muscle endurance, muscle mass, and cross-sectional area of muscle fibers, and increased the effect on muscle Atrogin-1 protein expression in the denervated mice. These in vivo results suggest that inorganic arsenic at doses relevant to humans may possess myoatrophic potential.

The Effect of ACL Reconstruction on Involved and Contralateral Limb Vastus Lateralis Morphology and Histology: A Pilot Study

2019 ◽  
Author(s):  
Eric C. Leszczynski ◽  
Christopher Kuenze ◽  
Brett Brazier ◽  
Joseph Visker ◽  
David P. Ferguson
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Cross Sectional Area ◽  
Vastus Lateralis Muscle ◽  
Myosin Isoforms ◽  
Sectional Area ◽  
Cross Sectional ◽  
Contralateral Limb ◽  
Significant Difference

AbstractQuadriceps muscle weakness is a commonly reported issue post anterior cruciate ligament reconstruction (ACLR), with minimal information related to skeletal muscle morphology following surgery. The purpose is to examine the morphological and functional differences in the vastus lateralis muscle from patient's ACLR and contralateral leg. Three physically active ACLR participants were recruited and secured to a dynamometer to perform maximal voluntary isometric knee extension contractions (MVIC) of the ACLR and contralateral limb. Muscle biopsies of the ACLR and contralateral vastus lateralis were performed, then sectioned, and stained for myosin isoforms to determine fiber type. Confocal images were acquired, and ImageJ software was used to determine the fiber type and cross-sectional area (CSA). There was a significant reduction in CSA of the type IIa and type IIx muscle fiber cells between healthy (IIa: 7,718 ± 1,295 µm2; IIx; 5,800 ± 601 µm2) and ACLR legs (IIa: 4,139 ± 709 µm2; IIx: 3,708 ± 618 µm2) (p < 0.05), while there was no significant difference in knee extension MVIC torque between legs (healthy limb: 2.42 ± 0.52 Nm/kg; ACLR limb: 2.05 ± 0.24 Nm/kg, p = 0.11). The reduction in the cross-sectional area of the ACLR type II fibers could impair function and increase secondary injury risk.

scholarly journals Association of Protein Intake in Three Meals with Muscle Mass in Healthy Young Subjects: A Cross-Sectional Study

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 612 ◽  
Author(s):  
Jun Yasuda ◽  
Mai Asako ◽  
Takuma Arimitsu ◽  
Satoshi Fujita
Keyword(s):  
Muscle Mass ◽  
Protein Intake ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Cross Sectional Study ◽  
Fat Free Mass ◽  
Intake Rate ◽  
Young Population ◽  
Cross Sectional ◽  
Young Subjects

Protein intake of >0.24 g/kg of body weight (BW) at a single meal is necessary to maximize muscle protein synthesis in a young population. However, the association between the protein intake rate for three meals and muscle mass in the young population has not been evaluated. We hypothesized that a protein intake of >0.24 g/kg BW at all three meals is effective for maintaining muscle mass. Therefore, we cross-sectionally examined the association between protein intake at all three meals with muscle mass in 266 healthy young subjects (aged 21.4 ± 2.4 years). Subjects were divided into the AP group, which achieved protein intake >0.24 g/kg BW at all three meals; and the NP group, which did not. We calculated total fat-free mass (FFM) and appendicular fat-free mass (AppFFM) with dual-energy X-ray absorptiometry, and the percentage of total FFM (TotalFFM%) and appendicular FFM (AppFFM%) were calculated as the percentage of BW (%BW). We demonstrated that TotalFFM% (77.0 ± 0.5 vs. 75.2 ± 0.4%, p = 0.008) and AppFFM% (34.7 ± 0.3 vs. 34.1 ± 0.2%, p = 0.058) were higher in the AP than in the NP group. This finding suggests that achieving protein intake of >0.24 g/kg BW at all three meals is important for muscle mass maintenance in young populations.

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