scholarly journals The effect of obesity on the contractile performance of isolated mouse soleus, EDL, and diaphragm muscles

2017 ◽  
Vol 122 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Jason Tallis ◽  
Cameron Hill ◽  
Rob S. James ◽  
Val M. Cox ◽  
Frank Seebacher
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Isometric Force ◽  
Muscle Performance ◽  
Muscle Quality ◽  
Control Group ◽  
Protein Kinase Activity ◽  
Negative Cycle ◽  
Contractile Performance

Obesity affects the major metabolic and cellular processes involved in skeletal muscle contractility. Surprisingly, the effect of obesity on isolated skeletal muscle performance remains unresolved. The present study is the first to examine the muscle-specific changes in contractility following dietary-induced obesity using an isolated muscle work-loop (WL) model that more closely represents in vivo muscle performance. Following 16-wk high-calorific feeding, soleus (SOL), extensor digitorum longus (EDL), and diaphragm (DIA) were isolated from female (CD-1) mice, and contractile performance was compared against a lean control group. Obese SOL produced greater isometric force; however, isometric stress (force per unit muscle area), absolute WL power, and normalized WL power (watts per kilogram muscle mass) were unaffected. Maximal isometric force and absolute WL power of the EDL were similar between groups. For both EDL and DIA, isometric stress and normalized WL power were reduced in the obese groups. Obesity caused a significant reduction in fatigue resistance in all cases. Our findings demonstrate a muscle-specific reduction in contractile performance and muscle quality that is likely related to in vivo mechanical role, fiber type, and metabolic profile, which may in part be related to changes in myosin heavy chain expression and AMP-activated protein kinase activity. These results infer that, beyond the additional requirement of moving a larger body mass, functional performance and quality of life may be further limited by poor muscle function in obese individuals. As such, a reduction in muscle performance may be a substantial contributor to the negative cycle of obesity. NEW & NOTEWORTHY The effect of obesity on isolated muscle function is surprisingly underresearched. The present study is the first to examine the effects of obesity on isolated muscle performance using a method that more closely represents real-world muscle function. This work uniquely establishes a muscle-specific profile of mechanical changes in relation to underpinning mechanisms. These findings may be important to understanding the negative cycle of obesity and in designing interventions for improving weight status.

scholarly journals Improved Tetanic Force and Mitochondrial Calcium Homeostasis by Astaxanthin Treatment in Mouse Skeletal Muscle

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 98 ◽  
Author(s):  
Sztretye ◽  
Singlár ◽  
Szabó ◽  
Angyal ◽  
Balogh ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Calcium Homeostasis ◽  
Inhibitory Effect ◽  
Calcium Transients ◽  
Muscle Performance ◽  
Control Group ◽  
Mitochondrial Calcium ◽  
Tetanic Force

Background: Astaxanthin (AX) a marine carotenoid is a powerful natural antioxidant which protects against oxidative stress and improves muscle performance. Retinol and its derivatives were described to affect lipid and energy metabolism. Up to date, the effects of AX and retinol on excitation-contraction coupling (ECC) in skeletal muscle are poorly described. Methods: 18 C57Bl6 mice were divided into two groups: Control and AX supplemented in rodent chow for 4 weeks (AstaReal A1010). In vivo and in vitro force and intracellular calcium homeostasis was studied. In some experiments acute treatment with retinol was employed. Results: The voltage activation of calcium transients (V50) were investigated in single flexor digitorum brevis isolated fibers under patch clamp and no significant changes were found following AX supplementation. Retinol shifted V50 towards more positive values and decreased the peak F/F0 of the calcium transients. The amplitude of tetani in the extensor digitorum longus was significantly higher in AX than in control group. Lastly, the mitochondrial calcium uptake was found to be less prominent in AX. Conclusion: AX supplementation increases in vitro tetanic force without affecting ECC and exerts a protecting effect on the mitochondria. Retinol treatment has an inhibitory effect on ECC in skeletal muscle.

Effect of in vivo inhibition of neutrophil adherence on skeletal muscle function during ischemia in ferrets

1991 ◽  
Vol 261 (4) ◽  
pp. H1178-H1183
Author(s):  
E. O. Weselcouch ◽  
R. I. Grove ◽  
C. D. Demusz ◽  
A. J. Baird
Keyword(s):  
Skeletal Muscle ◽  
Monoclonal Antibody ◽  
Muscle Function ◽  
Peak Force ◽  
Control Group ◽  
Protective Effects ◽  
Normal Flow ◽  
Skeletal Muscle Function ◽  
Time Curve

Neutrophils are reported to play an important role in the genesis of tissue damage during reperfusion after periods of ischemia in a variety of organs and may also be involved in loss of tissue function during ischemia. To test this hypothesis, the monoclonal antibody, MoAb 60.3, which prevents the adhesion of ferret neutrophils to cultured human endothelial cells at a concentration of 30 micrograms/ml, was tested in a model of peripheral vascular disease to determine whether it would preserve skeletal muscle function during ischemia. In an anesthetized ferret the muscles of the hindlimb were stimulated electrically to contract isometrically and the force of contraction was measured. Under normal perfusion conditions the contractile force peaked within 1 or 2 min of initiation of stimulation and gradually declined to approximately 80% of peak force after 20 min. When femoral arterial pressure was reduced to 45 mmHg by partial occlusion of the abdominal aorta, peak force was reduced by 25 +/- 7%, and within 5 min the force decayed to approximately 20% of the original peak, resulting in an area under the force-time curve (AUC) of 32 +/- 5% of that seen during the normal flow period. During ischemia after treatment with MoAb 60.3 (2 mg/kg iv), peak force was 94 +/- 3% and AUC was 49 +/- 5% of that observed during the normal flow period, a significant protective effect compared with the untreated control group (P = 0.0294). When the nonneutrophil-directed monoclonal antibody, L6, was tested in this model, no protective effects were evident.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Age-related changes in isolated mouse skeletal muscle function are dependent on sex, muscle, and contractility mode

2020 ◽  
Vol 319 (3) ◽  
pp. R296-R314
Author(s):  
Cameron Hill ◽  
Rob S. James ◽  
Val. M. Cox ◽  
Frank Seebacher ◽  
Jason Tallis
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Fatigue Resistance ◽  
Muscle Function ◽  
Isometric Force ◽  
Muscle Quality ◽  
Skeletal Muscle Function ◽  
Cross Sectional ◽  
Mouse Skeletal Muscle ◽  
Age Related

The present study aimed to simultaneously examine the age-related, muscle-specific, sex-specific, and contractile mode-specific changes in isolated mouse skeletal muscle function and morphology across multiple ages. Measurements of mammalian muscle morphology, isometric force and stress (force/cross-sectional area), absolute and normalized (power/muscle mass) work-loop power across a range of contractile velocities, fatigue resistance, and myosin heavy chain (MHC) isoform concentration were measured in 232 isolated mouse (CD-1) soleus, extensor digitorum longus (EDL), and diaphragm from male and female animals aged 3, 10, 30, 52, and 78 wk. Aging resulted in increased body mass and increased soleus and EDL muscle mass, with atrophy only present for female EDL by 78 wk despite no change in MHC isoform concentration. Absolute force and power output increased up to 52 wk and to a higher level for males. A 23–36% loss of isometric stress exceeded the 14–27% loss of power normalized to muscle mass between 10 wk and 52 wk, although the loss of normalized power between 52 and 78 wk continued without further changes in stress ( P > 0.23). Males had lower power normalized to muscle mass than females by 78 wk, with the greatest decline observed for male soleus. Aging did not cause a shift toward slower contractile characteristics, with reduced fatigue resistance observed in male EDL and female diaphragm. Our findings show that the loss of muscle quality precedes the loss of absolute performance as CD-1 mice age, with the greatest effect seen in male soleus, and in most instances without muscle atrophy or an alteration in MHC isoforms.

In vivo supraspinatus muscle contractility and architecture in rabbit

2020 ◽  
Vol 129 (6) ◽  
pp. 1405-1412
Author(s):  
Sydnee A. Hyman ◽  
Mackenzie B. Norman ◽  
Shanelle N. Dorn ◽  
Shannon N. Bremner ◽  
Mary C. Esparza ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Isometric Force ◽  
Muscle Physiology ◽  
Mammalian Skeletal Muscle ◽  
Improved Method ◽  
Muscle Contractility ◽  
Supraspinatus Muscle ◽  
Contractile Stress ◽  
Maximum Isometric Force

We introduce an improved method to assess rabbit supraspinatus muscle physiology. Maximum isometric force measured for the rabbit supraspinatus was dramatically greater than previous reports in the literature. Consequently, the isometric contractile stress reported is almost 10 times greater than previous reports of rabbit supraspinatus, but similar to available literature of other mammalian skeletal muscle. We show that previous reports of peak supraspinatus isometric force were subphysiological by ∼90%

scholarly journals Keratin 18 is an integral part of the intermediate filament network in murine skeletal muscle

2020 ◽  
Vol 318 (1) ◽  
pp. C215-C224 ◽  
Author(s):  
Joaquin M. Muriel ◽  
Andrea O’Neill ◽  
Jaclyn P. Kerr ◽  
Emily Kleinhans-Welte ◽  
Richard M. Lovering ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Isometric Force ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Type I ◽  
Mrna Levels ◽  
Force Transmission ◽  
Keratin 18 ◽  
Murine Skeletal Muscle

Intermediate filaments (IFs) contribute to force transmission, cellular integrity, and signaling in skeletal muscle. We previously identified keratin 19 (Krt19) as a muscle IF protein. We now report the presence of a second type I muscle keratin, Krt18. Krt18 mRNA levels are about half those for Krt19 and only 1:1,000th those for desmin; the protein was nevertheless detectable in immunoblots. Muscle function, measured by maximal isometric force in vivo, was moderately compromised in Krt18-knockout ( Krt18-KO) or dominant-negative mutant mice ( Krt18 DN), but structure was unaltered. Exogenous Krt18, introduced by electroporation, was localized in a reticulum around the contractile apparatus in wild-type muscle and to a lesser extent in muscle lacking Krt19 or desmin or both proteins. Exogenous Krt19, which was either reticular or aggregated in controls, became reticular more frequently in Krt19-null than in Krt18-null, desmin-null, or double-null muscles. Desmin was assembled into the reticulum normally in all genotypes. Notably, all three IF proteins appeared in overlapping reticular structures. We assessed the effect of Krt18 on susceptibility to injury in vivo by electroporating siRNA into tibialis anterior (TA) muscles of control and Krt19-KO mice and testing 2 wk later. Results showed a 33% strength deficit (reduction in maximal torque after injury) compared with siRNA-treated controls. Conversely, electroporation of siRNA to Krt19 into Krt18-null TA yielded a strength deficit of 18% after injury compared with controls. Our results suggest that Krt18 plays a complementary role to Krt19 in skeletal muscle in both assembling keratin-based filaments and transducing contractile force.

Effects of In Vivo Doxorubicin Treatment on Skeletal Muscle Function

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 903
Author(s):  
David S. Hydock ◽  
Chia-Ying Lien ◽  
Brock T. Jensen ◽  
Traci L. Parry ◽  
Carole M. Schneider ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Skeletal Muscle Function ◽  
Doxorubicin Treatment

Chronic rosiglitazone treatment restores AMPKα2 activity in insulin-resistant rat skeletal muscle

2006 ◽  
Vol 290 (2) ◽  
pp. E251-E257 ◽  
Author(s):  
Sarah J. Lessard ◽  
Zhi-Ping Chen ◽  
Matthew J. Watt ◽  
Michael Hashem ◽  
Julianne J. Reid ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Zucker Rats ◽  
Control Group ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ampk Signaling ◽  
Palmitate Oxidation ◽  
Insulin Resistant ◽  
Obese Zucker Rats

Rosiglitazone (RSG) is an insulin-sensitizing thiazolidinedione (TZD) that exerts peroxisome proliferator-activated receptor-γ (PPARγ)-dependent and -independent effects. We tested the hypothesis that part of the insulin-sensitizing effect of RSG is mediated through the action of AMP-activated protein kinase (AMPK). First, we determined the effect of acute (30–60 min) incubation of L6 myotubes with RSG on AMPK regulation and palmitate oxidation. Compared with control (DMSO), 200 μM RSG increased ( P < 0.05) AMPKα1 activity and phosphorylation of AMPK (Thr172). In addition, acetyl-CoA carboxylase (Ser218) phosphorylation and palmitate oxidation were increased ( P < 0.05) in these cells. To investigate the effects of chronic RSG treatment on AMPK regulation in skeletal muscle in vivo, obese Zucker rats were randomly allocated into two experimental groups: control and RSG. Lean Zucker rats were treated with vehicle and acted as a control group for obese Zucker rats. Rats were dosed daily for 6 wk with either vehicle (0.5% carboxymethylcellulose, 100 μl/100 g body mass), or 3 mg/kg RSG. AMPKα1 activity was similar in muscle from lean and obese animals and was unaffected by RSG treatment. AMPKα2 activity was ∼25% lower in obese vs. lean animals ( P < 0.05) but was normalized to control values after RSG treatment. ACC phosphorylation was decreased with obesity ( P < 0.05) but restored to the level of lean controls with RSG treatment. Our data demonstrate that RSG restores AMPK signaling in skeletal muscle of insulin-resistant obese Zucker rats.

scholarly journals Age-induced oxidative stress: how does it influence skeletal muscle quantity and quality?

2016 ◽  
Vol 121 (5) ◽  
pp. 1047-1052 ◽  
Author(s):  
Cory W. Baumann ◽  
Dongmin Kwak ◽  
Haiming M. Liu ◽  
LaDora V. Thompson
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Muscle Function ◽  
Strength Loss ◽  
Muscle Quality ◽  
Muscle Size ◽  
Nitrogen Species ◽  
Skeletal Muscle Function ◽  
Protein Balance ◽  
Ec Coupling

With advancing age, skeletal muscle function declines as a result of strength loss. These strength deficits are largely due to reductions in muscle size (i.e., quantity) and its intrinsic force-producing capacity (i.e., quality). Age-induced reductions in skeletal muscle quantity and quality can be the consequence of several factors, including accumulation of reactive oxygen and nitrogen species (ROS/RNS), also known as oxidative stress. Therefore, the purpose of this mini-review is to highlight the published literature that has demonstrated links between aging, oxidative stress, and skeletal muscle quantity or quality. In particular, we focused on how oxidative stress has the potential to reduce muscle quantity by shifting protein balance in a deficit, and muscle quality by impairing activation at the neuromuscular junction, excitation-contraction (EC) coupling at the ryanodine receptor (RyR), and cross-bridge cycling within the myofibrillar apparatus. Of these, muscle weakness due to EC coupling failure mediated by RyR dysfunction via oxidation and/or nitrosylation appears to be the strongest candidate based on the publications reviewed. However, it is clear that age-associated oxidative stress has the ability to alter strength through several mechanisms and at various locations of the muscle fiber.

scholarly journals Effectiveness of impedance parameters for muscle quality evaluation in healthy men

2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Hiroki Sato ◽  
Takao Nakamura ◽  
Toshimasa Kusuhara ◽  
Kobara Kenichi ◽  
Katsushi Kuniyasu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Muscle Thickness ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
Muscle Quality ◽  
Stepwise Multiple Regression ◽  
Skeletal Muscle Function ◽  
Healthy Men ◽  
Impedance Parameters

Abstract We investigated the relationship between impedance parameters and skeletal muscle function in the lower extremities, as well as the effectiveness of impedance parameters in evaluating muscle quality. Lower extremity impedance of 19 healthy men (aged 23–31 years) measured using the direct segmental multi-frequency bioelectrical impedance analysis were arc-optimized using the Cole–Cole model, following which phase angle (PA), $${R}_{i}/{R}_{e}$$ R i / R e , and β were estimated. Skeletal muscle function was assessed by muscle thickness, muscle intensity, and isometric knee extension force (IKEF). IKEF was positively correlated with PA (r = 0.58, p < 0.01) and β (r = 0.34, p < 0.05) was negatively correlated with $${R}_{i}/{R}_{e}$$ R i / R e (r = − 0.43, p < 0.01). Stepwise multiple regression analysis results revealed that PA, β, and $${R}_{i}/{R}_{e}$$ R i / R e were correlated with IKEF independently of muscle thickness. This study suggests that arc-optimized impedance parameters are effective for evaluating muscle quality and prediction of muscle strength.

Absence of myofibrillar creatine kinase and diaphragm isometric function during repetitive activation

1998 ◽  
Vol 84 (4) ◽  
pp. 1166-1173 ◽  
Author(s):  
John J. Labella ◽  
Monica J. Daood ◽  
A. P. Koretsky ◽  
Brian B. Roman ◽  
Gary C. Sieck ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Muscle Function ◽  
Isometric Force ◽  
Force Generation ◽  
Fatigue Properties ◽  
Specific Force ◽  
Null Mutant ◽  
Isometric Muscle

Creatine kinase (CK) provides ATP buffering in skeletal muscle and is expressed as 1) cytosolic myofibrillar CK (M-CK) and 2) sarcomeric mitochondrial CK (ScCKmit) isoforms that differ in their subcellular localization. We compared the isometric contractile and fatigue properties of 1) control CK-sufficient (Ctl), 2) M-CK-deficient (M-CK[−/−]), and 3) combined M-CK/ScCKmit-deficient null mutant (CK[−/−]) diaphragm (Dia) to determine the effect of the absence of M-CK activity on Dia performance in vitro. Baseline contractile properties were comparable across groups except for specific force, which was ∼16% lower in CK[−/−] Dia compared with M-CK[−/−] and Ctl Dia. During repetitive activation (40 Hz, [Formula: see text] duty cycle), force declined in all three groups. This decline was significantly greater in CK[−/−] Dia compared with Ctl and M-CK[−/−] Dia. The pattern of force decline did not differ between M-CK[−/−] and Ctl Dia. We conclude that Dia isometric muscle function is not absolutely dependent on the presence of M-CK, whereas the complete absence of CK acutely impairs isometric force generation during repetitive activation.

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