101
|
Abstract
Athletes and exercisers have utilised high-protein diets for centuries. The objective of this review is to examine the evidence for the efficacy and potential dangers of high-protein diets. One important factor to consider is the definition of a ‘high-protein diet’. There are several ways to consider protein content of a diet. The composition of the diet can be determined as the absolute amount of the protein (or other nutrient of interest), the % of total energy (calories) as protein and the amount of protein ingested per kg of body weight. Many athletes consume very high amounts of protein. High-protein diets most often are associated with muscle hypertrophy and strength, but now also are advocated for weight loss and recovery from intense exercise or injuries. Prolonged intake of a large amount of protein has been associated with potential dangers, such as bone mineral loss and kidney damage. In otherwise healthy individuals, there is little evidence that high protein intake is dangerous. However, kidney damage may be an issue for individuals with already existing kidney dysfunction. Increased protein intake necessarily means that overall energy intake must increase or consumption of either carbohydrate or fat must decrease. In conclusion, high protein intake may be appropriate for some athletes, but there are potential negative consequences that must be carefully considered before adopting such a diet. In particular, care must be taken to ensure that there is sufficient intake of other nutrients to support the training load.
Collapse
|
102
|
Barrios C, Hadala M, Almansa I, Bosch-Morell F, Palanca JM, Romero FJ. Metabolic muscle damage and oxidative stress markers in an America’s Cup yachting crew. Eur J Appl Physiol 2010; 111:1341-50. [DOI: 10.1007/s00421-010-1762-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2010] [Indexed: 11/30/2022]
|
103
|
Miyabara EH, Conte TC, Silva MT, Baptista IL, Bueno C, Fiamoncini J, Lambertucci RH, Serra CS, Brum PC, Pithon-Curi T, Curi R, Aoki MS, Oliveira AC, Moriscot AS. Mammalian target of rapamycin complex 1 is involved in differentiation of regenerating myofibers in vivo. Muscle Nerve 2010; 42:778-87. [PMID: 20976781 DOI: 10.1002/mus.21754] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This work was undertaken to provide further insight into the role of mammalian target of rapamycin complex 1 (mTORC1) in skeletal muscle regeneration, focusing on myofiber size recovery. Rats were treated or not with rapamycin, an mTORC1 inhibitor. Soleus muscles were then subjected to cryolesion and analyzed 1, 10, and 21 days later. A decrease in soleus myofiber cross-section area on post-cryolesion days 10 and 21 was accentuated by rapamycin, which was also effective in reducing protein synthesis in these freeze-injured muscles. The incidence of proliferating satellite cells during regeneration was unaltered by rapamycin, although immunolabeling for neonatal myosin heavy chain (MHC) was weaker in cryolesion+rapamycin muscles than in cryolesion-only muscles. In addition, the decline in tetanic contraction of freeze-injured muscles was accentuated by rapamycin. This study indicates that mTORC1 plays a key role in the recovery of muscle mass and the differentiation of regenerating myofibers, independently of necrosis and satellite cell proliferation mechanisms.
Collapse
Affiliation(s)
- Elen H Miyabara
- Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
104
|
Stock MS, Young JC, Golding LA, Kruskall LJ, Tandy RD, Conway-Klaassen JM, Beck TW. The effects of adding leucine to pre and postexercise carbohydrate beverages on acute muscle recovery from resistance training. J Strength Cond Res 2010; 24:2211-9. [PMID: 20634736 DOI: 10.1519/jsc.0b013e3181dc3a10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The present study examined the effects of adding leucine to pre and postexercise carbohydrate beverages on selected markers of muscle damage, delayed-onset muscle soreness (DOMS), and squat performance for up to 72 hours after lower-body resistance training. Seventeen resistance trained men (mean +/- SD age 22.9 +/- 2.9 years) and 3 resistance trained women (mean +/- SD age 21.6 +/- 2.6 years) performed 6 sets of squats to fatigue using 75% of the 1 repetition maximum. Each subject consumed a carbohydrate beverage 30 minutes before and immediately after exercise with or without the addition of 22.5 mgxkg (45 mgxkg total) of leucine in a randomized, double-blind fashion. Serum creatine kinase (CK), lactate dehydrogenase (LDH), and DOMS were analyzed immediately before (TIME1), 24 (TIME2), 48 (TIME3), and 72 (TIME4) hours after exercise. The subjects repeated the squat protocol at TIME4 to test recovery. No differences were observed between groups for squat performance, defined as the total number of repetitions performed during 6 sets of squats, for both TIME1 and TIME4. The addition of leucine did not significantly decrease CK and LDH activity or DOMS. These results suggested that adding leucine to carbohydrate beverages did not affect acute muscle recovery and squat performance during both initial testing and during a subsequent exercise bout 72 hours later in resistance trained subjects.
Collapse
Affiliation(s)
- Matt S Stock
- Department of Health and Exercise Science University of Oklahoma, Norman, Oklahoma, USA.
| | | | | | | | | | | | | |
Collapse
|
105
|
Barnes JN, Trombold JR, Dhindsa M, Lin HF, Tanaka H. Arterial stiffening following eccentric exercise-induced muscle damage. J Appl Physiol (1985) 2010; 109:1102-8. [DOI: 10.1152/japplphysiol.00548.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute inflammatory responses are linked to a transient increase in risk of a cardiovascular event, and this risk may be mediated by a concomitant reduction in vascular function. Humans experience an acute inflammatory response as a consequence of infection, injury, or muscle damage. We measured macrovascular function before and after eccentric exercise to determine whether muscle damage from unaccustomed exercise has an unfavorable effect on the large elastic arteries. A total of 27 healthy sedentary or recreationally active men (age 18–38 years) participated in either bilateral leg press eccentric exercise or unilateral elbow flexor eccentric exercise. Postexercise muscle damage was confirmed by significant reductions in isometric strength and increases in muscle soreness ( P < 0.05). Carotid-femoral pulse-wave velocity was significantly elevated 48 h after leg exercise (808 ± 31 vs. 785 ± 30 cm/s; P < 0.05) and arm exercise (790 ± 28 vs. 755 ± 24 cm/s; P < 0.05). There were no changes in mean arterial pressure. C-reactive protein was elevated after leg exercise but not after arm exercise. The increase in carotid-femoral pulse wave velocity 48 h after arm exercise was associated with muscle strength ( r = −0.47; P < 0.05) and creatine kinase concentrations ( r = 0.70; P < 0.01). We concluded that eccentric exercise in both small and large muscle mass translates to transient, unfavorable changes in central macrovascular function and that the increase in central arterial stiffness after small muscle eccentric exercise is associated with indicators of muscle damage.
Collapse
Affiliation(s)
- Jill N. Barnes
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| | - Justin R. Trombold
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| | - Mandeep Dhindsa
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| | - Hsin-Fu Lin
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| | - Hirofumi Tanaka
- Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas
| |
Collapse
|
106
|
Abstract
Muscle tissue may be damaged following intense prolonged training as a consequence of both metabolic and mechanical factors. Serum levels of skeletal muscle enzymes or proteins are markers of the functional status of muscle tissue, and vary widely in both pathological and physiological conditions. Creatine kinase, lactate dehydrogenase, aldolase, myoglobin, troponin, aspartate aminotransferase, and carbonic anhydrase CAIII are the most useful serum markers of muscle injury, but apoptosis in muscle tissues subsequent to strenuous exercise may be also triggered by increased oxidative stress. Therefore, total antioxidant status can be used to evaluate the level of stress in muscle by other markers, such as thiobarbituric acid-reactive substances, malondialdehyde, sulfhydril groups, reduced glutathione, oxidized glutathione, superoxide dismutase, catalase and others. As the various markers provide a composite picture of muscle status, we recommend using more than one to provide a better estimation of muscle stress.
Collapse
Affiliation(s)
- Paola Brancaccio
- Servizio di Medicina dello Sport, Seconda Università di Napoli, Napoli, Italy
| | | | | |
Collapse
|
107
|
Vincent B, Windelinckx A, Nielens H, Ramaekers M, Van Leemputte M, Hespel P, Thomis MA. Protective role of alpha-actinin-3 in the response to an acute eccentric exercise bout. J Appl Physiol (1985) 2010; 109:564-73. [PMID: 20507967 DOI: 10.1152/japplphysiol.01007.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ACTN3 gene encodes for the alpha-actinin-3 protein, which has an important structural function in the Z line of the sarcomere in fast muscle fibers. A premature stop codon (R577X) polymorphism in the ACTN3 gene causes a complete loss of the protein in XX homozygotes. This study investigates a possible role for the alpha-actinin-3 protein in protecting the fast fiber from eccentric damage and studies repair mechanisms after a single eccentric exercise bout. Nineteen healthy young men (10 XX, 9 RR) performed 4 series of 20 maximal eccentric knee extensions with both legs. Blood (creatine kinase; CK) and muscle biopsy samples were taken to study differential expression of several anabolic (MyoD1, myogenin, MRF4, Myf5, IGF-1), catabolic (myostatin, MAFbx, and MURF-1), and contraction-induced muscle damage marker genes [cysteine- and glycine-rich protein 3 (CSRP3), CARP, HSP70, and IL-6] as well as a calcineurin signaling pathway marker (RCAN1). Baseline mRNA content of CSRP3 and MyoD1 was 49 + or - 12 and 67 + or - 25% higher in the XX compared with the RR group (P = 0.01-0.045). However, satellite cell number was not different between XX and RR individuals. After eccentric exercise, XX individuals tended to have higher serum CK activity (P = 0.10) and had higher pain scores than RR individuals. However, CSRP3 (P = 0.058) and MyoD1 (P = 0.08) mRNA expression tended to be higher after training in RR individuals compared with XX alpha-actinin-3-deficient subjects. This study suggests a protective role of alpha-actinin-3 protein in muscle damage after eccentric training and an improved stress-sensor signaling, although effects are small.
Collapse
Affiliation(s)
- Barbara Vincent
- Research Center for Exercise and Health, Department of Biomedical Kinesiology, Faculty of Kinesiology and Rehabilitation Sciences, Katholieke Universiteit Leuven, Leuven
| | | | | | | | | | | | | |
Collapse
|
108
|
MacNeil LG, Melov S, Hubbard AE, Baker SK, Tarnopolsky MA. Eccentric exercise activates novel transcriptional regulation of hypertrophic signaling pathways not affected by hormone changes. PLoS One 2010; 5:e10695. [PMID: 20502695 PMCID: PMC2872670 DOI: 10.1371/journal.pone.0010695] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 04/16/2010] [Indexed: 01/21/2023] Open
Abstract
Unaccustomed eccentric exercise damages skeletal muscle tissue, activating mechanisms of recovery and remodeling that may be influenced by the female sex hormone 17β-estradiol (E2). Using high density oligonucleotide based microarrays, we screened for differences in mRNA expression caused by E2 and eccentric exercise. After random assignment to 8 days of either placebo (CON) or E2 (EXP), eighteen men performed 150 single-leg eccentric contractions. Muscle biopsies were collected at baseline (BL), following supplementation (PS), +3 hours (3H) and +48 hours (48H) after exercise. Serum E2 concentrations increased significantly with supplementation (P<0.001) but did not affect microarray results. Exercise led to early transcriptional changes in striated muscle activator of Rho signaling (STARS), Rho family GTPase 3 (RND3), mitogen activated protein kinase (MAPK) regulation and the downstream transcription factor FOS. Targeted RT-PCR analysis identified concurrent induction of negative regulators of calcineurin signaling RCAN (P<0.001) and HMOX1 (P = 0.009). Protein contents were elevated for RND3 at 3H (P = 0.02) and FOS at 48H (P<0.05). These findings indicate that early RhoA and NFAT signaling and regulation are altered following exercise for muscle remodeling and repair, but are not affected by E2.
Collapse
Affiliation(s)
- Lauren G. MacNeil
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Simon Melov
- Buck Institute for Age Research, Novato, California, United States of America
| | - Alan E. Hubbard
- School of Public Health, University of California, Berkeley, California, United States of America
| | - Steven K. Baker
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Mark A. Tarnopolsky
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
| |
Collapse
|
109
|
Liao P, Zhou J, Ji LL, Zhang Y. Eccentric contraction induces inflammatory responses in rat skeletal muscle: role of tumor necrosis factor-α. Am J Physiol Regul Integr Comp Physiol 2010; 298:R599-607. [DOI: 10.1152/ajpregu.00480.2009] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eccentric contraction (EC) is known to elicit inflammation and damage in skeletal muscle. Proinflammatory cytokine TNF-α plays an important role in this pathogenesis, but the time course of its response to EC and the regulatory mechanisms involved are not clear. The purpose of the study is twofold: 1) to investigate the gene expression of TNF-α in rat muscle during and after an acute bout of downhill running and the associated oxidoreductive (redox) changes; and 2) to examine whether EC activates muscle ubiquitin-proteolytic pathway resulting in necrosis and oxidative damage. Female Sprague-Dawley rats (age 3 mo) were randomly divided into five groups ( n = 6) that ran on treadmill at 25 m/min at −10% grade for 1 h ( group 1) or 2 h ( group 2) and were killed immediately; ran for 2 h and killed at 6 h after exercise ( group 3), ran for 2 h and killed at 24 h after exercise ( group 4); and killed at rest as controls ( group 5). TNF-α mRNA and protein content showed progressive increases in the deep portion of vastus lateralis (DVL) and gastrocnemius muscles during and after EC. These changes were accompanied by a progressive decrease of mitochondrial aconitase activity and NF-κB activation. After 2 h of exercise, elevated levels of serum TNF-α, endotoxin, creatine kinase, and lipid peroxidation marker were evident and persisted through 24 h postexercise. At 24 h, there were marked increases in H2O2 concentration, myleoperoxidase activity, and endotoxin level, along with nuclear accumulation of p65, in both muscles. mRNA level of ubiquitin-conjugating enzymes (E2)-14k was progressively upregulated during exercise and recovery, whereas the expression of the Toll-like receptor 4 (TLR4) in DVL was downregulated in both muscles. We conclude that prolonged EC induces TNF-α expression possibly due to NF-κB activation stimulated by increased reactive oxygen species generation and endotoxin release. These inflammatory and prooxidative responses may underlie the processes of muscle proteolysis and oxidative damage.
Collapse
Affiliation(s)
- Peng Liao
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin, China; and
| | - Jinping Zhou
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin, China; and
| | - Li Li Ji
- Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Yong Zhang
- Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin University of Sport, Tianjin, China; and
| |
Collapse
|
110
|
TROMBOLD JUSTINR, BARNES JILLN, CRITCHLEY LEAH, COYLE EDWARDF. Ellagitannin Consumption Improves Strength Recovery 2-3 d after Eccentric Exercise. Med Sci Sports Exerc 2010; 42:493-8. [DOI: 10.1249/mss.0b013e3181b64edd] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
|
111
|
Burnley ECD, Olson AN, Sharp RL, Baier SM, Alekel DL. Impact of Protein Supplements on Muscle Recovery After Exercise-induced Muscle Soreness. J Exerc Sci Fit 2010. [DOI: 10.1016/s1728-869x(10)60014-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
112
|
Vinciguerra M, Musaro A, Rosenthal N. Regulation of Muscle Atrophy in Aging and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 694:211-33. [DOI: 10.1007/978-1-4419-7002-2_15] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
113
|
Intramuscular adaptations to eccentric exercise and antioxidant supplementation. Amino Acids 2009; 39:219-32. [PMID: 19967420 DOI: 10.1007/s00726-009-0432-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 11/17/2009] [Indexed: 01/09/2023]
Abstract
Prophylactic supplementation of N-acetyl-cysteine (NAC) and epigallocatechin gallate (EGCG) was studied for physiological and cellular changes in skeletal muscle after eccentric muscle contractions. Thirty healthy, active males (20.0 +/- 1.8 years, 160 +/- 7.1 cm, 76.1 +/- 17.0 kg) ingested for 14 days either 1,800 mg of NAC, 1,800 mg of EGCG, or 1,000 mg of fiber (glucomannan) placebo (PLC) in a double blind, prophylactic fashion. Subjects completed one eccentric exercise bout (100 repetitions at 30 degrees /s) using the dominant knee extensors. Strength and soreness were assessed, and blood and muscle samples obtained before and 6, 24, 48, and 72 h with no muscle sample being collected at 72 h. Separate mixed factorial repeated measures ANOVA (P < 0.05) were used for all statistical analysis. All groups experienced significantly reduced peak torque production after 6 and 24 h, increased soreness at all time points from baseline [with even greater soreness levels 24 h after exercise in PLC when compared to EGCG and NAC (P < 0.05)], increased lactate dehydrogenase at 6 h, and increased creatine kinase 6, 24 and 48 h after exercise. No significant group x time interaction effects were found for serum cortisol, neutrophil counts, and the neutrophil:lymphocyte ratio; although, all values experienced significant changes 6 h after exercise (P < 0.05), but at no other time points. At 48 h after the exercise bout the Neu:Lym ratio in EGCG was significantly less than NAC (P < 0.05), whereas there was a trend (P = 0.08) for the EGCG values to be less when compared to PLC at this time point. Markers of intramuscular mitochondrial and cytosolic apoptosis were assessed (e.g., bax, bcl-2, cytochrome C, caspase-3 content/enzyme activity, and total DNA content). Significant increases (P < 0.05) in muscle levels of bax and bcl-2 were observed in all groups with no significant differences between groups, whereas no changes (P > 0.05) were reported for cytochrome C, caspase-3 content, caspase-3 enzyme activity, and total DNA. Caspase-3 enzyme activity was significantly greater in all groups 48 h after exercise when compared to baseline (P < 0.05) and 6 h (P < 0.05) after exercise. An eccentric bout of muscle contractions appears to significantly increase muscle damage, markers of mitochondrial apoptosis, apoptotic enzyme activity, and whole-blood cell markers of inflammation with no changes in oxidative stress. While soreness ratings were blunted in the two supplementation groups 24 h after exercise when compared to PLC values, more research is needed to determine the potential impact of EGCG and NAC supplementation on changes related to oxidative stress, apoptosis, and eccentric exercise.
Collapse
|
114
|
Zhang L, Ran L, Garcia GE, Wang XH, Han S, Du J, Mitch WE. Chemokine CXCL16 regulates neutrophil and macrophage infiltration into injured muscle, promoting muscle regeneration. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:2518-27. [PMID: 19893053 DOI: 10.2353/ajpath.2009.090275] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Only a few specific chemokines that mediate interactions between inflammatory and satellite cells in muscle regeneration have been identified. The chemokine CXCL16 differs from other chemokines because it has both a transmembrane region and active, soluble chemokine forms. Indeed, we found increased expression of CXCL16 and its receptor, CXCR6, in regenerating myofibers. Muscle regeneration in CXCL16-deficient (CXCL16KO) mice was severely impaired compared with regeneration in wild-type mice. In addition, there was decreased MyoD and myogenin expression in regenerating muscle in CXCL16KO mice, indicating impaired satellite cell proliferation and differentiation. After 1 month, new myofibers in CXCL16KO mice remained significantly smaller than those in muscle of wild-type mice. To understand how CXCL16 regulates muscle regeneration, we examined cells infiltrating injured muscle. There were more infiltrating neutrophils and fewer macrophages in injured muscle of CXCL16KO mice compared with events in wild-type mice. Moreover, absence of CXCL16 led to different expression of cytokines/chemokines in injured muscles: mRNAs of macrophage-inflammatory protein (MIP)-1alpha, MIP-1beta, and MIP-2 were increased, whereas regulated on activation normal T cell expressed and secreted, T-cell activation-3, and monocyte chemoattractant protein-1 mRNAs were lower compared with results in muscles of wild-type mice. Impaired muscle regeneration in CXCL16KO mice also resulted in fibrosis, which was linked to transforming growth factor-beta1 expression. Thus, CXCL16 expression is a critical mediator of muscle regeneration, and it suppresses the development of fibrosis.
Collapse
Affiliation(s)
- Liping Zhang
- Nephrology Division, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | | | | | |
Collapse
|
115
|
Sudo M, Kano Y. Myofiber apoptosis occurs in the inflammation and regeneration phase following eccentric contractions in rats. J Physiol Sci 2009; 59:405-12. [PMID: 19636670 PMCID: PMC10717303 DOI: 10.1007/s12576-009-0049-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 06/24/2009] [Indexed: 10/20/2022]
Abstract
Eccentric contractions (ECC) induce myofibrillar collapse, edema, and inflammation in muscle cells. Although apoptosis of myonuclei following ECC is activated during the inflammatory phase, the apoptosis response of the regenerative phase remains to be elucidated. The aim of the present study was to determine the inflammatory and regenerative phase of the apoptosis responses induced by ECC. In anesthetized rats, the tibialis anterior muscles were subjected to ECC repeated 40 times, evoked by surface electric stimulation (100 Hz, 10 V) with mechanical muscle stretch. Apoptosis was examined in the control group and in groups 1, 3, 7, and 14 days after ECC (each group, n = 4-6). Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive myonuclei were assessed by further labeling with dystrophin staining and DAPI. The expression of proteins related to apoptosis (Bcl-2 and Bax) was examined by Western blot assay. At 1 and 3 days, focal edema and necrotic myofibers invaded by mononuclear phagocytes were present, whereas regenerated myofibers with central nuclei were detected at 7 and 14 days. The occurrence of TUNEL-positive myonuclei increased significantly at 7 (7.0 +/- 1.5%) and 14 days (5.6 +/- 0.6%) compared with control (0.9 +/- 0.5%). Further we found that myonuclear apoptosis was restricted to the subsarcolemmal space at 7 and 14 days and markedly absent from the central nucleus. The Bax/Bcl-2 ratio was significantly higher at 3 (4.5 +/- 0.9) and 7 days (3.4 +/- 0.5) after ECC. In conclusion, myofiber apoptotic responses following ECC are present not only in the inflammatory phase but also persist during the regenerative phase.
Collapse
Affiliation(s)
- Mizuki Sudo
- Department of Applied Physics and Chemistry, University of Electro-Communications, Chofu, Tokyo 1828585 Japan
| | - Yutaka Kano
- Department of Applied Physics and Chemistry, University of Electro-Communications, Chofu, Tokyo 1828585 Japan
| |
Collapse
|
116
|
[Exercise therapy and myopathies]. Rev Neurol (Paris) 2009; 166:269-78. [PMID: 19656541 DOI: 10.1016/j.neurol.2009.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 05/23/2009] [Accepted: 07/01/2009] [Indexed: 11/20/2022]
Abstract
Since the first consensus papers published early in the 2000s, a growing number of recent publications has shown that adapted physical activity is not only safe in the context of myopathy but also potentially effective as a therapeutic tool. After a short recall of the different exercise modalities, the mechanical strain they induce and the expected muscular benefits, the present paper reviews the different studies related to exercise therapy in myopathic patients and provides a critical analysis of the topic. Myopathies are rare diseases with many different etiologies and a large number of training modalities which could be useful for the different muscular challenges have been proposed. We have chosen to focus on several specific training modalities and to discuss the results from the most recent papers. The purpose of this review is to, firstly, update physical training guidelines for patients with myopathy and, secondly, highlight some common pitfalls associated with this strategy. This is particularly important for medical and allied professionals involved in prescribing and managing exercise therapy protocols.
Collapse
|
117
|
Vissing K, Bayer ML, Overgaard K, Schjerling P, Raastad T. Heat shock protein translocation and expression response is attenuated in response to repeated eccentric exercise. Acta Physiol (Oxf) 2009; 196:283-93. [PMID: 19032600 DOI: 10.1111/j.1748-1716.2008.01940.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
AIM This study hypothesized that heat shock protein (HSP) translocation and upregulation is more probable to occur after eccentric exercise than after concentric exercise or repeated eccentric exercise. METHODS Fourteen young, healthy, untrained male subjects completed two bench-stepping exercise bouts with 8 weeks between bouts, and were compared with a control group (n = 6). Muscle biopsies collected from m. vastus lateralis of both legs prior to and at 3 h, 24 h and 7 days after exercise were quantified for mRNA levels and/or for HSP27, alphabeta-crystallin and inducible HSP70 content in cytosolic and cytoskeletal protein fractions. RESULTS The first bout of exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P < 0.05). These responses were attenuated after the repeated eccentric exercise bout (P < 0.05), suggesting a repeated bout adaptation. Increases in inducible HSP70 and HSP27 protein content in cytoskeletal fractions were observed exclusively after eccentric exercise (P < 0.05). For HSP27, an approx. 10-fold upregulation after first-bout eccentric exercise was attenuated to a an approximately fourfold upregulation after the repeated eccentric exercise bout. mRNA levels for HSP70, HSP27 and alphabeta-crystallin were upregulated within approximately two to fourfold ranges at time points 3 and 24 h post-exercise (P < 0.05). This upregulation was induced exclusively by eccentric exercise but with a tendency to attenuated expression 3 h after the repeated eccentric exercise bout. CONCLUSION Our results show that HSP translocation and expression responses are induced by muscle damaging exercise, and suggest that such HSP responses are closely related to the extent of muscle damage.
Collapse
Affiliation(s)
- K Vissing
- Department of Sport Science, University of Aarhus, Aarhus, Denmark.
| | | | | | | | | |
Collapse
|
118
|
Cutlip RG, Baker BA, Hollander M, Ensey J. Injury and adaptive mechanisms in skeletal muscle. J Electromyogr Kinesiol 2009; 19:358-72. [DOI: 10.1016/j.jelekin.2008.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 06/23/2008] [Accepted: 06/23/2008] [Indexed: 11/29/2022] Open
|
119
|
Lomonosova YN, Zheleznyakova AV, Bugrova AE, Zhiryakova AV, Kalamkarov GR, Nemirovskaya TL. Protective effect of nitric oxide on cytoskeletal proteins in rat soleus under eccentric exercise. Biophysics (Nagoya-shi) 2009. [DOI: 10.1134/s0006350909030191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
120
|
Tiidus PM, Enns DL. Point:Counterpoint: Estrogen and sex do/do not influence post-exercise indexes of muscle damage, inflammation, and repair. J Appl Physiol (1985) 2009; 106:1010-2; discussion 1014-15, 1021. [DOI: 10.1152/japplphysiol.90848.2008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
121
|
Hubal MJ, Clarkson PM. Counterpoint: Estrogen and Sex do not Significantly Influence Post-Exercise Indexes of Muscle Damage, Inflammation, and Repair. J Appl Physiol (1985) 2009; 106:1012-4; discussion 1014, 1022. [DOI: 10.1152/japplphysiol.90848.2008a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
122
|
Pizza FX. Comments on Point:Counterpoint: Estrogen and sex do/do not influence post-exercise indexes of muscle damage, inflammation, and repair. J Appl Physiol (1985) 2009; 106:1016-20. [DOI: 10.1152/japplphysiol.00004.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
|
123
|
Murton A, Constantin D, Greenhaff P. The involvement of the ubiquitin proteasome system in human skeletal muscle remodelling and atrophy. Biochim Biophys Acta Mol Basis Dis 2008; 1782:730-43. [DOI: 10.1016/j.bbadis.2008.10.011] [Citation(s) in RCA: 190] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 10/23/2008] [Accepted: 10/24/2008] [Indexed: 12/14/2022]
|
124
|
Davies RC, Eston RG, Poole DC, Rowlands AV, DiMenna F, Wilkerson DP, Twist C, Jones AM. Effect of eccentric exercise-induced muscle damage on the dynamics of muscle oxygenation and pulmonary oxygen uptake. J Appl Physiol (1985) 2008; 105:1413-21. [DOI: 10.1152/japplphysiol.90743.2008] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unaccustomed eccentric exercise has a profound impact on muscle structure and function. However, it is not known whether associated microvascular dysfunction disrupts the matching of O2delivery (Q̇o2) to O2utilization (V̇o2). Near-infrared spectroscopy (NIRS) was used to test the hypothesis that eccentric exercise-induced muscle damage would elevate the muscle Q̇o2:V̇o2ratio during severe-intensity exercise while preserving the speed of the V̇o2kinetics at exercise onset. Nine physically active men completed “step” tests to severe-intensity exercise from an unloaded baseline on a cycle ergometer before (Pre) and 48 h after (Post) eccentric exercise (100 squats with a load corresponding to 70% of body mass). NIRS and breath-by-breath pulmonary V̇o2were measured continuously during the exercise tests and subsequently modeled using standard nonlinear regression techniques. There were no changes in phase II pulmonary V̇o2kinetics following the onset of exercise (time constant: Pre, 25 ± 4 s; Post, 24 ± 2 s; amplitude: Pre, 2.36 ± 0.23 l/min; Post, 2.37 ± 0.23 l/min; all P > 0.05). However, the primary (Pre, 14 ± 3 s; Post, 19 ± 3 s) and overall (Pre, 16 ± 4 s; Post, 21 ± 4 s) mean response time of the [HHb] response was significantly slower following eccentric exercise ( P < 0.05). The slower [HHb] kinetics observed following eccentric exercise is consistent with an increased Q̇o2:V̇o2ratio during transitions to severe-intensity exercise. We propose that unchanged primary phase V̇o2kinetics are associated with an elevated Q̇o2:V̇o2ratio that preserves blood-myocyte O2flux.
Collapse
|
125
|
KERKSICK CHAD, TAYLOR LEM, HARVEY ALISON, WILLOUGHBY DARRYN. Gender-Related Differences in Muscle Injury, Oxidative Stress, and Apoptosis. Med Sci Sports Exerc 2008; 40:1772-80. [DOI: 10.1249/mss.0b013e31817d1cce] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
126
|
Futier E, Constantin JM, Combaret L, Mosoni L, Roszyk L, Sapin V, Attaix D, Jung B, Jaber S, Bazin JE. Pressure support ventilation attenuates ventilator-induced protein modifications in the diaphragm. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 12:R116. [PMID: 18786263 PMCID: PMC2592744 DOI: 10.1186/cc7010] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 07/31/2008] [Accepted: 09/11/2008] [Indexed: 11/10/2022]
Abstract
Introduction Controlled mechanical ventilation (CMV) induces profound modifications of diaphragm protein metabolism, including muscle atrophy and severe ventilator-induced diaphragmatic dysfunction. Diaphragmatic modifications could be decreased by spontaneous breathing. We hypothesized that mechanical ventilation in pressure support ventilation (PSV), which preserves diaphragm muscle activity, would limit diaphragmatic protein catabolism. Methods Forty-two adult Sprague-Dawley rats were included in this prospective randomized animal study. After intraperitoneal anesthesia, animals were randomly assigned to the control group or to receive 6 or 18 hours of CMV or PSV. After sacrifice and incubation with 14C-phenylalanine, in vitro proteolysis and protein synthesis were measured on the costal region of the diaphragm. We also measured myofibrillar protein carbonyl levels and the activity of 20S proteasome and tripeptidylpeptidase II. Results Compared with control animals, diaphragmatic protein catabolism was significantly increased after 18 hours of CMV (33%, P = 0.0001) but not after 6 hours. CMV also decreased protein synthesis by 50% (P = 0.0012) after 6 hours and by 65% (P < 0.0001) after 18 hours of mechanical ventilation. Both 20S proteasome activity levels were increased by CMV. Compared with CMV, 6 and 18 hours of PSV showed no significant increase in proteolysis. PSV did not significantly increase protein synthesis versus controls. Both CMV and PSV increased protein carbonyl levels after 18 hours of mechanical ventilation from +63% (P < 0.001) and +82% (P < 0.0005), respectively. Conclusions PSV is efficient at reducing mechanical ventilation-induced proteolysis and inhibition of protein synthesis without modifications in the level of oxidative injury compared with continuous mechanical ventilation. PSV could be an interesting alternative to limit ventilator-induced diaphragmatic dysfunction.
Collapse
Affiliation(s)
- Emmanuel Futier
- General Intensive Care Unit, Hotel-Dieu Hospital, University Hospital of Clermont-Ferrand, Boulevard L. Malfreyt, Clermond-Ferrand, 63058, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
127
|
Grounds MD, Radley HG, Lynch GS, Nagaraju K, De Luca A. Towards developing standard operating procedures for pre-clinical testing in the mdx mouse model of Duchenne muscular dystrophy. Neurobiol Dis 2008; 31:1-19. [PMID: 18499465 DOI: 10.1016/j.nbd.2008.03.008] [Citation(s) in RCA: 247] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 03/20/2008] [Accepted: 03/24/2008] [Indexed: 11/19/2022] Open
Abstract
This review discusses various issues to consider when developing standard operating procedures for pre-clinical studies in the mdx mouse model of Duchenne muscular dystrophy (DMD). The review describes and evaluates a wide range of techniques used to measure parameters of muscle pathology in mdx mice and identifies some basic techniques that might comprise standardised approaches for evaluation. While the central aim is to provide a basis for the development of standardised procedures to evaluate efficacy of a drug or a therapeutic strategy, a further aim is to gain insight into pathophysiological mechanisms in order to identify other therapeutic targets. The desired outcome is to enable easier and more rigorous comparison of pre-clinical data from different laboratories around the world, in order to accelerate identification of the best pre-clinical therapies in the mdx mouse that will fast-track translation into effective clinical treatments for DMD.
Collapse
Affiliation(s)
- Miranda D Grounds
- School of Anatomy and Human Biology, the University of Western Australia, Perth, Western Australia, Australia.
| | | | | | | | | |
Collapse
|
128
|
Sonobe T, Inagaki T, Poole DC, Kano Y. Intracellular calcium accumulation following eccentric contractions in rat skeletal muscle in vivo: role of stretch-activated channels. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1329-37. [DOI: 10.1152/ajpregu.00815.2007] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although the accumulation of intracellular calcium ions ([Ca2+]i) is associated with muscle damage, little is known regarding the temporal profile of muscle [Ca2+]iunder in vivo conditions, and, specifically, the effects of different contraction types [e.g., isometric (ISO); eccentric (ECC)] on [Ca2+]iremain to be determined. The following hypotheses were tested. 1) For 90 min at rest, an in vivo vs. in vitro preparation would better maintain initial [Ca2+]i. 2) Compared with ISO, ECC contractions (50 contractions, 10 sets, 5-min interval) would lead to a greater increase of [Ca2+]i. 3) Elevated [Ca2+]iduring ECC would be reduced or prevented by the stretch-activated ion channel blockers streptomycin and gadolinium (Gd3+). Spinotrapezius muscles of Wistar rats were exteriorized (in vivo) or excised (in vitro). [Ca2+]iwas evaluated by loading the muscle with fura 2-AM using fluorescence imaging. [Ca2+]irose progressively beyond 40 min at rest under in vitro but not in vivo conditions during the 90-min protocol. In vivo [Ca2+]iincreased more rapidly during ECC (first set) than ISO (fifth set) ( P < 0.05 vs. precontraction values). The peak level of [Ca2+]iwas increased by 21.5% (ISO) and 42.8% (ECC) after 10 sets (both P < 0.01). Streptomycin and Gd3+abolished the majority of [Ca2+]iincrease during ECC (69 and 86% reduction, respectively; P < 0.01 from peak [Ca2+]iof ECC). In conclusion, in vivo quantitative analyses demonstrated that ECC contractions elevate [Ca2+]isignificantly more than ISO contractions and that stretch-activated channels may play a permissive role in this response.
Collapse
|
129
|
Hubal MJ, Chen TC, Thompson PD, Clarkson PM. Inflammatory gene changes associated with the repeated-bout effect. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1628-37. [PMID: 18353886 DOI: 10.1152/ajpregu.00853.2007] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study proposed that attenuated expression of inflammatory factors is an underlying mechanism driving the repeated-bout effect (rapid adaptation to eccentric exercise). We investigated changes in mRNA levels and protein localization of inflammatory genes after two bouts of muscle-lengthening exercise. Seven male subjects performed two bouts of lower body exercise (separated by 4 wk) in which one leg performed 300 eccentric-concentric actions, and the contralateral leg performed 300 concentric actions only. Vastus lateralis biopsies were collected at 6 h, and strength was assessed at baseline and at 0, 3, and 5 days after exercise. mRNA levels were measured via semiquantitative RT-PCR for the following genes: CYR61, HSP40, HSP70, IL1R1, TCF8, ZFP36, CEBPD, and MCP1. Muscle functional adaptation was demonstrated via attenuated strength loss (16% less, P = 0.04) at 5 days after bout 2 compared with bout 1 in the eccentrically exercised leg. mRNA expression of three of the eight genes tested was significantly elevated in the eccentrically exercised leg from bout 1 to bout 2 (+3.9-fold for ZFP36, +2.3-fold for CEBPD, and +2.6-fold for MCP1), while all eight mRNA levels were unaffected by bout in the concentrically exercised leg. Immunohistochemistry further localized the protein of one of the elevated factors [monocyte chemoattractant protein-1 (MCP1)] within the tissue. MCP1 colocalized with resident macrophage and satellite cell populations, suggesting that alterations in cytokine signaling between these cell populations may play a role in muscle adaptation to exercise. Contrary to our hypothesis, several inflammatory genes were transcriptionally upregulated (rather than attenuated) after a repeated exercise bout, potentially indicating a role for these genes in the adaptation process.
Collapse
Affiliation(s)
- Monica J Hubal
- Department of Kinesiology, University of Massachusetts, Amherst, MA, USA.
| | | | | | | |
Collapse
|
130
|
Effects of concentric and repeated eccentric exercise on muscle damage and calpain-calpastatin gene expression in human skeletal muscle. Eur J Appl Physiol 2008; 103:323-32. [PMID: 18340456 DOI: 10.1007/s00421-008-0709-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2008] [Indexed: 10/22/2022]
Abstract
The purpose of this study was to compare the responsiveness of changes in Ca(2+)-content and calpain-calpastatin gene expression to concentric and eccentric single-bout and repeated exercise. An exercise group (n = 14) performed two bouts of bench-stepping exercise with 8 weeks between exercise bouts, and was compared to a control-group (n = 6). Muscle strength and soreness and plasma creatine kinase and myoglobin were measured before and during 7 days following exercise bouts. Muscle biopsies were collected from m. vastus lateralis of both legs prior to and at 3, 24 h and 7 days after exercise and quantified for muscle Ca(2+)-content and mRNA levels for calpain isoforms and calpastatin. Exercise reduced muscle strength and increased muscle soreness predominantly in the eccentric leg (P < 0.05). These responses as well as plasma levels of creatine kinase and myoglobin were all attenuated after the repeated eccentric exercise bout (P < 0.05). Total muscle Ca(2+)-content did not differ between interventions. mRNA levels for calpain 2 and calpastatin were upregulated exclusively by eccentric exercise 24 h post-exercise (P < 0.05), with no alteration in expression between bouts. Calpain 1 and calpain 3 mRNA did not change at any specific time point post-exercise for either intervention. Our mRNA results suggest a regulation on the calpain-calpastatin expression response to muscle damaging eccentric exercise, but not concentric exercise. Although a repeated bout effect was demonstrated in terms of muscle function, no immediate support was provided to suggest that regulation of expression of specific system components is involved in the repeated bout adaptation.
Collapse
|
131
|
Mahoney DJ, Safdar A, Parise G, Melov S, Fu M, MacNeil L, Kaczor J, Payne ET, Tarnopolsky MA. Gene expression profiling in human skeletal muscle during recovery from eccentric exercise. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1901-10. [PMID: 18321953 DOI: 10.1152/ajpregu.00847.2007] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used cDNA microarrays to screen for differentially expressed genes during recovery from exercise-induced muscle damage in humans. Male subjects (n = 4) performed 300 maximal eccentric contractions, and skeletal muscle biopsy samples were analyzed at 3 h and 48 h after exercise. In total, 113 genes increased 3 h postexercise, and 34 decreased. At 48 h postexercise, 59 genes increased and 29 decreased. On the basis of these data, we chose 19 gene changes and conducted secondary analyses using real-time RT-PCR from muscle biopsy samples taken from 11 additional subjects who performed an identical bout of exercise. Real-time RT-PCR analyses confirmed that exercise-induced muscle damage led to a rapid (3 h) increase in sterol response element binding protein 2 (SREBP-2), followed by a delayed (48 h) increase in the SREBP-2 gene targets Acyl CoA:cholesterol acyltransferase (ACAT)-2 and insulin-induced gene 1 (insig-1). The expression of the IL-1 receptor, a known regulator of SREBP-2, was also elevated after exercise. Taken together, these expression changes suggest a transcriptional program for increasing cholesterol and lipid synthesis and/or modification. Additionally, damaging exercise induced the expression of protein kinase H11, capping protein Z alpha (capZalpha), and modulatory calcineurin-interacting protein 1 (MCIP1), as well as cardiac ankryin repeat protein 1 (CARP1), DNAJB2, c-myc, and junD, each of which are likely involved in skeletal muscle growth, remodeling, and stress management. In summary, using DNA microarrays and RT-PCR, we have identified novel genes that respond to skeletal muscle damage, which, given the known biological functions, are likely involved in recovery from and/or adaptation to damaging exercise.
Collapse
Affiliation(s)
- D J Mahoney
- Department of Medical Sciences, McMaster University Medical Center, 1200 Main Street W., Hamilton, Ontario, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
132
|
SEWRIGHT KIMBERLYA, HUBAL MONICAJ, KEARNS AMY, HOLBROOK MARIKOT, CLARKSON PRISCILLAM. Sex Differences in Response to Maximal Eccentric Exercise. Med Sci Sports Exerc 2008; 40:242-51. [DOI: 10.1249/mss.0b013e31815aedda] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
133
|
Abstract
Skeletal muscle is a malleable tissue capable of altering the type and amount of protein in response to disruptions to cellular homeostasis. The process of exercise-induced adaptation in skeletal muscle involves a multitude of signalling mechanisms initiating replication of specific DNA genetic sequences, enabling subsequent translation of the genetic message and ultimately generating a series of amino acids that form new proteins. The functional consequences of these adaptations are determined by training volume, intensity and frequency, and the half-life of the protein. Moreover, many features of the training adaptation are specific to the type of stimulus, such as the mode of exercise. Prolonged endurance training elicits a variety of metabolic and morphological changes, including mitochondrial biogenesis, fast-to-slow fibre-type transformation and substrate metabolism. In contrast, heavy resistance exercise stimulates synthesis of contractile proteins responsible for muscle hypertrophy and increases in maximal contractile force output. Concomitant with the vastly different functional outcomes induced by these diverse exercise modes, the genetic and molecular mechanisms of adaptation are distinct. With recent advances in technology, it is now possible to study the effects of various training interventions on a variety of signalling proteins and early-response genes in skeletal muscle. Although it cannot presently be claimed that such scientific endeavours have influenced the training practices of elite athletes, these new and exciting technologies have provided insight into how current training techniques result in specific muscular adaptations, and may ultimately provide clues for future and novel training methodologies. Greater knowledge of the mechanisms and interaction of exercise-induced adaptive pathways in skeletal muscle is important for our understanding of the aetiology of disease, maintenance of metabolic and functional capacity with aging, and training for athletic performance. This article highlights the effects of exercise on molecular and genetic mechanisms of training adaptation in skeletal muscle.
Collapse
Affiliation(s)
- Vernon G Coffey
- School of Medical Sciences, Exercise Metabolism Group, RMIT University, Melbourne, Victoria, Australia
| | | |
Collapse
|
134
|
Cruzat VF, Rogero MM, Borges MC, Tirapegui J. Aspectos atuais sobre estresse oxidativo, exercícios físicos e suplementação. REV BRAS MED ESPORTE 2007. [DOI: 10.1590/s1517-86922007000500011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
As espécies reativas de oxigênio (ERO) são normalmente produzidas pelo metabolismo corporal. Todavia, ERO apresentam a capacidade de retirar elétrons de outros compostos celulares, sendo capazes de provocar lesões oxidativas em várias moléculas, fato que leva à perda total da função celular. A realização de exercícios físicos aumenta a síntese de ERO, além de promover lesão muscular e inflamação. Após uma sessão de exercícios físicos, inicia-se normalmente a fase de recuperação, quando são observados diversos efeitos positivos à saúde, incluindo o aumento da resistência a novas lesões induzidas ou não por exercícios, fato que é considerado como um processo "adaptativo". Diversos estudos, porém, relatam que essa recuperação não é alcançada por indivíduos que se submetem a exercícios intensos e prolongados, ou, ainda, que possuem elevada freqüência de treinamento. Alternativas nutricionais têm sido muito estudadas, a fim de reduzir os efeitos promovidos pelo exercício extenuante, dentre as quais está a suplementação com vitamina E, vitamina C, creatina e glutamina. Esta revisão tem como objetivo abordar os aspectos atuais envolvendo a formação das ERO, os processos de lesão celular e inflamação, a adaptação aos tipos de exercício aeróbio e anaeróbio e possíveis intervenções nutricionais.
Collapse
|
135
|
Coffey VG, Hawley JA. The molecular bases of training adaptation. SPORTS MEDICINE (AUCKLAND, N.Z.) 2007. [PMID: 17722947 DOI: 10.2165/00007256-200737090-00001.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Skeletal muscle is a malleable tissue capable of altering the type and amount of protein in response to disruptions to cellular homeostasis. The process of exercise-induced adaptation in skeletal muscle involves a multitude of signalling mechanisms initiating replication of specific DNA genetic sequences, enabling subsequent translation of the genetic message and ultimately generating a series of amino acids that form new proteins. The functional consequences of these adaptations are determined by training volume, intensity and frequency, and the half-life of the protein. Moreover, many features of the training adaptation are specific to the type of stimulus, such as the mode of exercise. Prolonged endurance training elicits a variety of metabolic and morphological changes, including mitochondrial biogenesis, fast-to-slow fibre-type transformation and substrate metabolism. In contrast, heavy resistance exercise stimulates synthesis of contractile proteins responsible for muscle hypertrophy and increases in maximal contractile force output. Concomitant with the vastly different functional outcomes induced by these diverse exercise modes, the genetic and molecular mechanisms of adaptation are distinct. With recent advances in technology, it is now possible to study the effects of various training interventions on a variety of signalling proteins and early-response genes in skeletal muscle. Although it cannot presently be claimed that such scientific endeavours have influenced the training practices of elite athletes, these new and exciting technologies have provided insight into how current training techniques result in specific muscular adaptations, and may ultimately provide clues for future and novel training methodologies. Greater knowledge of the mechanisms and interaction of exercise-induced adaptive pathways in skeletal muscle is important for our understanding of the aetiology of disease, maintenance of metabolic and functional capacity with aging, and training for athletic performance. This article highlights the effects of exercise on molecular and genetic mechanisms of training adaptation in skeletal muscle.
Collapse
Affiliation(s)
- Vernon G Coffey
- School of Medical Sciences, Exercise Metabolism Group, RMIT University, Melbourne, Victoria, Australia
| | | |
Collapse
|
136
|
Nedergaard A, Vissing K, Overgaard K, Kjaer M, Schjerling P. Expression patterns of atrogenic and ubiquitin proteasome component genes with exercise: effect of different loading patterns and repeated exercise bouts. J Appl Physiol (1985) 2007; 103:1513-22. [PMID: 17690190 DOI: 10.1152/japplphysiol.01445.2006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Unaccustomed exercise is known to produce strength loss, soreness, and myocellular disruption. With repeated application of exercise stimuli, the appearance of these indexes of muscle damage is attenuated, the so-called "repeated bout effect." No direct connection has been established between this repeated bout effect and exercise-induced increases in protein turnover, but it appears that a degree of tolerance is developed toward exercise for both. The present study sought to investigate markers of protein degradation by determining the expression of components related to the ubiquitin-proteasome system (UPS) with repeated exercise bouts. Healthy men carried out 30 min of bench stepping, performing eccentric work with one and concentric work with the other leg (n = 14), performing a duplicate exercise bout 8 wk later. A nonexercising control group was included (n = 6). RNA was extracted from muscle biopsies representing time points preexercise, +3 h, +24 h, and +7 days, and selected mRNA species were quantified using Northern blotting. The exercise model proved sufficient to produce a repeated bout effect in terms of strength and soreness. For forkhead box O transcription factor 1 (FOXO1) and muscle RING finger protein-1 (MURF1), strong upregulations were seen exclusively with concentric loading (P < 0.001), while atrogin-1 displayed a strong downregulation exclusively in response to eccentric exercise (P < 0.001). For MURF1 transcription, the first bout produced a downregulation that persisted until the second bout (P < 0.01). In conclusion, the UPS is modulated differentially in response to varying loading modalities and with different time frames in a way that to some extent reflects changes in protein metabolism known to take place with exercise.
Collapse
Affiliation(s)
- A Nedergaard
- Institute of Sports Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
| | | | | | | | | |
Collapse
|
137
|
Murphy RM, Goodman CA, McKenna MJ, Bennie J, Leikis M, Lamb GD. Calpain-3 is autolyzed and hence activated in human skeletal muscle 24 h following a single bout of eccentric exercise. J Appl Physiol (1985) 2007; 103:926-31. [PMID: 17585039 DOI: 10.1152/japplphysiol.01422.2006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The function and normal regulation of calpain-3, a muscle-specific Ca(2+)-dependent protease, is uncertain, although its absence leads to limb-girdle muscular dystrophy type 2A. This study examined the effect of eccentric exercise on calpain-3 autolytic activation, because such exercise is known to damage sarcomeric structures and to trigger adaptive changes that help prevent such damage on subsequent exercise. Six healthy human subjects performed a 30-min bout of one-legged, eccentric, knee extensor exercise. Torque measurements, vastus lateralis muscle biopsies, and venous blood samples were taken before and up to 7 days following the exercise. Peak isometric muscle torque was depressed immediately and at 3 h postexercise and recovered by 24 h, and serum creatine kinase concentration peaked at 24 h postexercise. The amount of autolyzed calpain-3 was unchanged immediately and 3 h after exercise, but increased markedly (from approximately 16% to approximately 35% of total) 24 h after the exercise, and returned to preexercise levels within 7 days. In contrast, the eccentric exercise produced little autolytic activation of the ubiquitous Ca(2+)-activated protease, mu-calpain. Eccentric exercise is the first physiological circumstance shown to result in calpain-3 activation in vivo.
Collapse
Affiliation(s)
- Robyn M Murphy
- Department of Zoology, La Trobe University, Victoria 3086, Australia.
| | | | | | | | | | | |
Collapse
|
138
|
Larsen RG, Ringgaard S, Overgaard K. Localization and quantification of muscle damage by magnetic resonance imaging following step exercise in young women. Scand J Med Sci Sports 2007; 17:76-83. [PMID: 17305942 DOI: 10.1111/j.1600-0838.2006.00525.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Eccentric exercise affects muscles differentially according to intensity, duration, and previous exposure to the specific exercise activity. We used T2-weighted magnetic resonance imaging sequences to localize and quantify muscle damage following step exercise and to determine correlations between transverse relaxation time (T2) and other markers of muscle damage. Eight women performed two-step exercise bouts (30 min) separated by 8 weeks. Blood samples, MR scans, measurements of muscle strength, and muscle soreness were obtained immediately before, after, and up to 9 days after each bout. Resting muscle T2 (40.3+/-0.6 ms) increased exclusively in m. Adductor magnus (AM) in the thigh performing eccentric contractions and peaked 3 days after bout 1 (73.5+/-9.7 ms, P<0.05). Plasma creatine kinase (CK) activity peaked on day 3 after bout 1 and correlated with T2 in AM (r=0.96, P<0.001). After bout 2 CK and T2 were almost unaffected. This indicates that T2-weighted MRI can be applied to identify muscles from which enzymes are being released into the circulation.
Collapse
Affiliation(s)
- R G Larsen
- Department of Sport Science, University of Aarhus, Aarhus, Denmark
| | | | | |
Collapse
|
139
|
Moncayo R, Moncayo H. A musculoskeletal model of low grade connective tissue inflammation in patients with thyroid associated ophthalmopathy (TAO): the WOMED concept of lateral tension and its general implications in disease. BMC Musculoskelet Disord 2007; 8:17. [PMID: 17319961 PMCID: PMC1820789 DOI: 10.1186/1471-2474-8-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 02/23/2007] [Indexed: 12/16/2022] Open
Abstract
Background Low level connective tissue inflammation has been proposed to play a role in thyroid associated ophthalmopathy (TAO). The aim of this study was to investigate this postulate by a musculoskeletal approach together with biochemical parameters. Methods 13 patients with TAO and 16 controls were examined. Erythrocyte levels of Zn, Cu, Ca2+, Mg, and Fe were determined. The musculoskeletal evaluation included observational data on body posture with emphasis on the orbit-head region. The angular foot position in the frontal plane was quantified following gait observation. The axial orientation of the legs and feet was evaluated in an unloaded supine position. Functional propioceptive tests based on stretch stimuli were done by using foot inversion and foot rotation. Results Alterations in the control group included neck tilt in 3 cases, asymmetrical foot angle during gait in 2, and a reaction to foot inversion in 5 cases. TAO patients presented facial asymmetry with displaced eye fissure inclination (mean 9.1°) as well as tilted head-on-neck position (mean 5.7°). A further asymmetry feature was external rotation of the legs and feet (mean 27°). Both foot inversion as well as foot rotation induced a condition of neuromuscular deficit. This condition could be regulated by gentle acupressure either on the lateral abdomen or the lateral ankle at the acupuncture points gall bladder 26 or bladder 62, respectively. In 5 patients, foot rotation produced a phenomenon of moving toes in the contra lateral foot. In addition foot rotation was accompanied by an audible tendon snapping. Lower erythrocyte Zn levels and altered correlations between Ca2+, Mg, and Fe were found in TAO. Conclusion This whole body observational study has revealed axial deviations and body asymmetry as well as the phenomenon of moving toes in TAO. The most common finding was an arch-like displacement of the body, i.e. eccentric position, with foot inversion and head tilt to the contra lateral side and tendon snapping. We propose that eccentric muscle action over time can be the basis for a low grade inflammatory condition. The general implications of this model and its relations to Zn and Se will be discussed.
Collapse
Affiliation(s)
- Roy Moncayo
- WOMED, Karl-Kapferer-Strasse 5, A-6020 Innsbruck, Austria
| | - Helga Moncayo
- WOMED, Karl-Kapferer-Strasse 5, A-6020 Innsbruck, Austria
| |
Collapse
|
140
|
Abstract
Neutrophils have not consistently been detected in exercise-injured skeletal muscle and, therefore, neutrophil infiltration in this muscle has become a controversial issue. Thirty-eight animal and human studies that assessed injured muscle for neutrophils and employed acute exercise (e.g. level, uphill or downhill running, eccentric contractions, or swimming) were analysed to help clarify the relationship between neutrophil infiltration and exercise-induced muscle injury. Findings from nearly three-quarters of the reviewed studies suggest that neutrophil accumulation follows exercise-induced muscle injury. Intramuscular neutrophil infiltration was present in 85% and 55% of the animal and human studies, respectively. However, no consistent relationship between the potential damaging effect of the exercise type and neutrophil infiltration can be conclusively established from these studies. Specific animal-related factors that could influence these results include age, animal strain, catecholamines, corticosterone, acute stressors and muscle type, whereas a specific human-related influencing factor is physical activity status. Factors affecting both animal and human studies could include sex hormones, muscle sampling techniques and neutrophil detection approaches. General categories of methods that have been used to detect neutrophil infiltration are microscopy, myeloperoxidase (MPO) biochemical assay, antibody staining and white blood cell radionuclide imaging. Only studies employing white blood cell radionuclide imaging have consistently detected neutrophil infiltration. However, antibody staining with a quantitative analysis is currently the most feasible, valid and sensitive method. Research recommendations, therefore, are warranted to resolve the neutrophil infiltration controversy. We propose two approaches for animal studies. The first approach encompasses (i) studying or measuring factors that could influence neutrophil infiltration; (ii) using quantitative antibody staining analysis (in all studies and employing a panel of anti-neutrophil antibodies); (iii) examining the relationship between fibre morphological changes and neutrophil antigen expression; and (iv) developing a neutrophil antibody-radionuclide imaging technique. The second approach will yield animal findings complementing or addressing the gaps from the human exercise studies. For human studies, we suggest that (i) physical activity status is investigated; (ii) quantitative antibody staining analysis is performed (including staining injured muscle with a panel of antibodies such as anti-elastase, anti-MPO, anti-CD11b and anti-CD15 or assessing injured muscle using both immunohistochemistry and the MPO biochemical assay); and (iii) the relationship between fibre morphological changes and neutrophil antigen expression is examined. Studies that incorporate these recommendations could lead to an increased understanding of whether neutrophils are essential for the recovery from an exercise-induced muscle injury.
Collapse
|
141
|
Hesselink MKC, Minnaard R, Schrauwen P. Eat the meat or feed the meat: protein turnover in remodeling muscle. Curr Opin Clin Nutr Metab Care 2006; 9:672-6. [PMID: 17053418 DOI: 10.1097/01.mco.0000247471.64532.7d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE OF REVIEW The present review outlines the role of muscle protein turnover in muscle remodeling, with emphasis on the effects of nutrition and exercise. RECENT FINDINGS Progress in our understanding of the pathways signaling and regulating protein synthesis and degradation, and thus protein turnover, in skeletal muscle has been substantial over the past decade. Protein synthesis and degradation jointly allow the active remodeling of skeletal muscle to adapt to changes in mechanical and metabolic demand. Nutrition and exercise are potent ways to stimulate protein turnover. This occurs in an amino acid and exercise-type (resistance versus endurance) and mode (lengthening and shortening)-specific manner. SUMMARY For optimal muscle remodeling, the timing and type of feeding and exercise appear to be crucial.
Collapse
Affiliation(s)
- Matthijs K C Hesselink
- Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Department of Movement Sciences, Maastricht University, 6200 MD Maastricht, the Netherlands.
| | | | | |
Collapse
|
142
|
Bartoli M, Bourg N, Stockholm D, Raynaud F, Delevacque A, Han Y, Borel P, Seddik K, Armande N, Richard I. A mouse model for monitoring calpain activity under physiological and pathological conditions. J Biol Chem 2006; 281:39672-80. [PMID: 17056592 DOI: 10.1074/jbc.m608803200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Calpains are Ca(2+)-dependent cysteine proteases known to be important for the regulation of cell functions and which aberrant activation causes cell death in a number of degenerative disorders. To provide a tool for monitoring the status of calpain activity in vivo under physiological and pathological conditions, we created a mouse model that expresses ubiquitously a fluorescent reporter consisting of eCFP and eYFP separated by a linker cleavable by the ubiquitous calpains. We named this mouse CAFI for calpain activity monitored by FRET imaging. Our validation studies demonstrated that the level of calpain activity correlates with a decrease in FRET (fluorescence resonance energy transfer) between the two fluorescent proteins. Using this model, we observed a small level of activity after denervation and fasting, a high level of activity during muscle regeneration and ischemia, and local activity in damaged myofibers after exercise. Finally, we crossed the CAFI mouse with the alpha-sarcoglycan-deficient model, demonstrating an increase of calpain activity at the steady state. Altogether, our results present evidence that CAFI mice could be a valuable tool in which to follow calpain activity at physiological levels and in disease states.
Collapse
Affiliation(s)
- Marc Bartoli
- Généthon/CNRS-UMR8115, 1 rue de l'Internationale 91000 Evry, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
143
|
Baker BA, Mercer RR, Geronilla KB, Kashon ML, Miller GR, Cutlip RG. Stereological analysis of muscle morphology following exposure to repetitive stretch-shortening cycles in a rat model. Appl Physiol Nutr Metab 2006; 31:167-79. [PMID: 16604135 DOI: 10.1139/h05-009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Repetitive motion is one risk factor associated with contraction-induced muscle injury, which leads to skeletal muscle degeneration, inflammation, and dysfunction. Since current methods are unable to quantify the acute degenerative and inflammatory responses of muscle tissue concurrently, the purpose of this study was to quantify the temporal myofiber response after exposure to injurious stretch-shortening cycles (SSCs) using a standardized stereological technique. Functional testing was performed on the ankle dorsiflexor muscles of Sprague-Dawley rats in vivo. Rats were anesthetized and exposed to 15 sets of 10 SSCs. Control rats were exposed to 15 sets of single isometric contractions of the same stimulation duration. Changes in muscle morphometry were assessed at 0.5, 24, 48, 72, and 240 h post-exposure to quantify the degree of myofiber degeneration and inflammation in the tibialis anterior muscle from each group. There was an increase in the volume density and average thickness of degenerating myofibers over time in the muscle collected from rats exposed to SSCs (p < 0.0001) that was significantly greater than in muscle exposed to isometric contractions at 24, 48, and 72 h post-exposure (p = 0.003). The volume density of degenerative myofibers was associated with functional deficits at 48 h. Stereological quantification of degenerative myofibers and interstitial space changes were associated with functional defects 48-72 h after SSC-induced injury, thus demonstrating stereology is an accurate measure of SSC-induced skeletal muscle injury.
Collapse
Affiliation(s)
- Brent A Baker
- National Institute for Occupational Safety and Health, Morgantown, VA 26505, USA
| | | | | | | | | | | |
Collapse
|
144
|
Dupont-Versteegden EE, Fluckey JD, Knox M, Gaddy D, Peterson CA. Effect of flywheel-based resistance exercise on processes contributing to muscle atrophy during unloading in adult rats. J Appl Physiol (1985) 2006; 101:202-12. [PMID: 16601304 DOI: 10.1152/japplphysiol.01540.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Flywheel-based resistance exercise (RE) attenuates muscle atrophy during hindlimb suspension. We have previously shown that protein synthesis is elevated in response to RE, but the effect on protein degradation, cell proliferation, or apoptosis was not investigated. We hypothesized that, in addition to affecting protein synthesis, RE inhibits processes that actively contribute to muscle atrophy during hindlimb suspension. Male rats were housed in regular cages (control), tail suspended for 2 wk (HS), or HS with RE every other day for 2 wk (HSRE). Although RE attenuated soleus muscle atrophy during HS, the observed fivefold elevation in apoptosis and the 53% decrease in cell proliferation observed with HS were unaffected by RE. Expression of genes encoding components of the ubiquitin-proteasome pathway of protein degradation were elevated with HS, including ubiquitin, MAFbx, Murf-1, Nedd4, and XIAP, and proteasome subunits C2 and C9. Total ubiquitinated protein was increased with HS, but proteasome activity was not different from control. RE selectively altered the expression of different components of this pathway: MAFbx, Murf-1, and ubiquitin mRNA abundance were downregulated, whereas C2 and C9 subunits remained elevated. Similarly, Nedd4 and XIAP continued to be upregulated, potentially accounting for the observed augmentation in total ubiquitinated protein with RE. Thus a different constellation of proteins is likely ubiquitinated with RE due to altered ubiquitin ligase composition. In summary, the flywheel-based resistance exercise paradigm used in this study is associated with the inhibition of some mechanisms associated with muscle atrophy, such as the increase in MAFbx and Murf-1, but not with others, such as proteasome subunit remodeling, apoptosis, and decreased proliferation, potentially accounting for the inability to completely restore muscle mass. Identifying specific exercise parameters that affect these latter processes may be useful in designing effective exercise strategies in the elderly or during spaceflight.
Collapse
Affiliation(s)
- Esther E Dupont-Versteegden
- Department of Geriatrics, University of Arkansas for Medical Sciences, 4301 West Markham #807, Little Rock, Arkansas 72205, USA.
| | | | | | | | | |
Collapse
|
145
|
Molnar AM, Servais S, Guichardant M, Lagarde M, Macedo DV, Pereira-Da-Silva L, Sibille B, Favier R. Mitochondrial H2O2 production is reduced with acute and chronic eccentric exercise in rat skeletal muscle. Antioxid Redox Signal 2006; 8:548-58. [PMID: 16677099 DOI: 10.1089/ars.2006.8.548] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Oxidative stress with acute/chronic exercise has been so far examined using exercise involving a combination of concentric and eccentric contractions, but skeletal muscles are likely to be injured to a greater extent by pliometric contractions. In the present study, the effects of acute and chronic bouts of downhill running exercise on mitochondrial hydrogen peroxide (H2O2) generation (fluorimetric detection of a dimer with homovanillic acid in presence of horseradish peroxidase) and oxygen consumption in conjunction with antioxidant enzymes activity were examined. The results show that acute eccentric exercise was accompanied by a significantly reduced mitochondrial H2O2 production that is likely due to a decrease in complex I of the electron transport chain (ETC). On the other hand, eccentric training leads to positive adaptations, reflected by a higher citrate synthase activity and decreased mitochondrial H2O2 production. The decrease in mitochondrial H2O2 cannot be attributed to alterations in antioxidant capacities but rather to changes in mitochondrial membrane composition characterized by an increased polyunsaturated to saturated fatty acids ratio, and decreased contents in arachidonic acid and plasmalogens. These results suggest that changes in mitochondrial membrane properties with eccentric training can affect H2O2 production by muscle mitochondria. It is hypothesized that these changes resulted in a mild uncoupling sufficient to reduce electron back flow through complex I of the ETC, the major generator of reactive oxygen species by skeletal muscle mitochondria.
Collapse
Affiliation(s)
- A M Molnar
- Unité Mixte Recherche 5123 CNRS, Université Claude Bernard-Lyon 1, Villeurbanne, France
| | | | | | | | | | | | | | | |
Collapse
|
146
|
Thompson HS, Scordilis SP, De Souza MJ. Serum creatine kinase activity varies with ovulatory status in regularly exercising, premenopausal women. HORMONE RESEARCH 2006; 65:151-8. [PMID: 16514242 DOI: 10.1159/000091805] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Accepted: 01/03/2006] [Indexed: 12/24/2022]
Abstract
BACKGROUND/AIMS The clinical complications associated with an unopposed estrogen environment and luteal phase defects observed in exercising women prompted the examination of the relationship of exercise and endogenous ovarian steroids with serum creatine kinase (CK) activity. METHODS Subjects (n = 34) were classified into three groups according to their exercise and menstrual status, sedentary and exercising ovulatory groups (SedOvul, ExOvul), and an exercising amenorrheic group (ExAmen). Daily urine samples were collected to assess urinary ovarian steroid exposure and menstrual status. Serum CK activity was assayed in each menstrual cycle of all subjects. RESULTS Exercise increased serum CK activity in all exercising subjects (p < 0.01), but the increase was greater in amenorrheic women compared to ovulatory women (SedOvul: 33.0 +/- 3.4; ExOvul: 43.7 +/- 4.1; ExAmen: 54.4 +/- 3.6, p < 0.05). When the ovulatory women were further divided into those with normal steroid production (ExOvul subgroup) and those with a suppressed progesterone luteal phase environment (ExLPD), both the ExOvul (51.9 +/- 5.4 IU/l) subgroup and ExAmen group had higher serum CK activity (p < 0.05) than the ExLPD (36.6 +/- 5.2 IU/l) subjects or the sedentary controls. CONCLUSIONS These data demonstrate the complex association between ovarian hormone status and the normal serum CK response to regular mechanical stress imposed by chronic exercise training.
Collapse
Affiliation(s)
- Heather S Thompson
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Mass., USA
| | | | | |
Collapse
|
147
|
Blazevich AJ, Sharp NCC. Understanding Muscle Architectural Adaptation: Macro- and Micro-Level Research. Cells Tissues Organs 2006; 181:1-10. [PMID: 16439814 DOI: 10.1159/000089964] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2005] [Indexed: 12/28/2022] Open
Abstract
Recent research using muscle-imaging techniques has revealed a remarkable plasticity of human muscle architecture where significant changes in fascicle lengths and angles have resulted from the chronic performance, or cessation, of strong muscle contractions. However, there is a paucity of data describing architectural adaptations to chronic stretching, disuse and immobilization, illness, and aging, and those data that are available are equivocal. Understanding their impact is important in order that effective interventions for illness/injury management and rehabilitation, and programs to improve the physical capacity of workers, the aged and athletes can be determined. Nonetheless, recent advances in myocellular research could provide a framework allowing the prediction of architectural changes in these understudied areas. Examination of the site-specific response to mechanical stress of calpain-dependent ubiquitin-proteasome proteolysis, or of the cellular response to stress after the knockout (or incapacitation) of sarcomeric and cytoskeletal proteins involved in cellular signal transduction, provides an exciting paradigm by which myocellular adaptation can be described. Such research might contribute to the understanding of macro-level changes in muscle architecture.
Collapse
Affiliation(s)
- Anthony J Blazevich
- Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge UB8 3PH, UK
| | | |
Collapse
|
148
|
Warren GL, O'farrell L, Rogers KR, Billings KM, Sayers SP, Clarkson PM. CK-MM autoantibodies: Prevalence, immune complexes, and effect on CK clearance. Muscle Nerve 2006; 34:335-46. [PMID: 16810680 DOI: 10.1002/mus.20594] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although the blood level of creatine kinase (CK) is the most commonly used marker of muscle injury, there is marked interindividual variability in this measure. Part of this variability may be attributed to variability in the rate of CK clearance from the circulation. In this study, we assessed the possibility that CK-MM autoantibodies form immune complexes with CK following muscle injury and subsequently affect the CK clearance rate. Using an enzyme-linked immunosorbent assay, CK-MM autoantibodies were detected in all 25 human subjects studied but the levels varied greatly. Using protein A-sepharose, the percentage of the plasma CK activity found in immune complexes was determined to be correlated with the CK-MM autoantibody level at lower CK levels (<1,022 U/L). When CK-MM antibodies were administered to mice, plasma CK activity following a bolus CK injection was reduced by 11%-32%. We conclude that CK-MM autoantibodies can modulate the rate of CK clearance from the circulation. Thus, the relatively low blood CK levels seen in some individuals following injury may be attributed partly or entirely to an autoantibody-enhanced clearance of CK.
Collapse
MESH Headings
- Adult
- Animals
- Antigen-Antibody Complex/immunology
- Autoantibodies/blood
- Autoantibodies/immunology
- Creatine Kinase, MM Form/blood
- Creatine Kinase, MM Form/immunology
- Female
- Humans
- Interleukin-6/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/immunology
- Muscle, Skeletal/injuries
- Myositis/immunology
- Myositis/metabolism
- Nervous System Autoimmune Disease, Experimental/immunology
- Nervous System Autoimmune Disease, Experimental/metabolism
- Receptors, CCR2
- Receptors, CCR5/genetics
- Receptors, Chemokine/genetics
- Seroepidemiologic Studies
Collapse
Affiliation(s)
- Gordon L Warren
- Division of Physical Therapy, Georgia State University, Atlanta, Georgia 30302, USA.
| | | | | | | | | | | |
Collapse
|
149
|
Miller BF, Olesen JL, Hansen M, Døssing S, Crameri RM, Welling RJ, Langberg H, Flyvbjerg A, Kjaer M, Babraj JA, Smith K, Rennie MJ. Coordinated collagen and muscle protein synthesis in human patella tendon and quadriceps muscle after exercise. J Physiol 2005; 567:1021-33. [PMID: 16002437 PMCID: PMC1474228 DOI: 10.1113/jphysiol.2005.093690] [Citation(s) in RCA: 417] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We hypothesized that an acute bout of strenuous, non-damaging exercise would increase rates of protein synthesis of collagen in tendon and skeletal muscle but these would be less than those of muscle myofibrillar and sarcoplasmic proteins. Two groups (n = 8 and 6) of healthy young men were studied over 72 h after 1 h of one-legged kicking exercise at 67% of maximum workload (W(max)). To label tissue proteins in muscle and tendon primed, constant infusions of [1-(13)C]leucine or [1-(13)C]valine and flooding doses of [(15)N] or [(13)C]proline were given intravenously, with estimation of labelling in target proteins by gas chromatography-mass spectrometry. Patellar tendon and quadriceps biopsies were taken in exercised and rested legs at 6, 24, 42 or 48 and 72 h after exercise. The fractional synthetic rates of all proteins were elevated at 6 h and rose rapidly to peak at 24 h post exercise (tendon collagen (0.077% h(-1)), muscle collagen (0.054% h(-1)), myofibrillar protein (0.121% h(-1)), and sarcoplasmic protein (0.134% h(-1))). The rates decreased toward basal values by 72 h although rates of tendon collagen and myofibrillar protein synthesis remained elevated. There was no tissue damage of muscle visible on histological evaluation. Neither tissue microdialysate nor serum concentrations of IGF-I and IGF binding proteins (IGFBP-3 and IGFBP-4) or procollagen type I N-terminal propeptide changed from resting values. Thus, there is a rapid increase in collagen synthesis after strenuous exercise in human tendon and muscle. The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation.
Collapse
Affiliation(s)
- Benjamin F Miller
- Institute of Sports Medicine, Copenhagen, Bispebjerg Hospital, Denmark
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
150
|
Kano Y, Padilla DJ, Behnke BJ, Hageman KS, Musch TI, Poole DC. Effects of eccentric exercise on microcirculation and microvascular oxygen pressures in rat spinotrapezius muscle. J Appl Physiol (1985) 2005; 99:1516-22. [PMID: 15994245 DOI: 10.1152/japplphysiol.00069.2005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A single bout of eccentric exercise results in muscle damage, but it is not known whether this is correlated with microcirculatory dysfunction. We tested the following hypotheses in the spinotrapezius muscle of rats either 1 (DH-1; n = 6) or 3 (DH-3; n = 6) days after a downhill run to exhaustion (90-120 min; -14 degrees grade): 1) in resting muscle, capillary hemodynamics would be impaired, and 2) at the onset of subsequent acute concentric contractions, the decrease of microvascular O(2) pressure (Pmv(o(2))), which reflects the dynamic balance between O(2) delivery and O(2) utilization, would be accelerated compared with control (Con, n = 6) rats. In contrast to Con muscles, intravital microscopy observations revealed the presence of sarcomere disruptions in DH-1 and DH-3 and increased capillary diameter in DH-3 (Con: 5.2 +/- 0.1; DH-1: 5.1 +/- 0.1; DH-3: 5.6 +/- 0.1 mum; both P < 0.05 vs. DH-3). At rest, there was a significant reduction in the percentage of capillaries that sustained continuous red blood cell (RBC) flux in both DH running groups (Con: 90.0 +/- 2.1; DH-1: 66.4 +/- 5.2; DH-3: 72.9 +/- 4.1%, both P < 0.05 vs. Con). Capillary tube hematocrit was elevated in DH-1 but reduced in DH-3 (Con: 22 +/- 2; DH-1: 28 +/- 1; DH-3: 16 +/- 1%; all P < 0.05). Although capillary RBC flux did not differ between groups (P > 0.05), RBC velocity was lower in DH-1 compared with Con (Con: 324 +/- 43; DH-1: 212 +/- 30; DH-3: 266 +/- 45 mum/s; P < 0.05 DH-1 vs. Con). Baseline Pmv(O(2)) before contractions was not different between groups (P > 0.05), but the time constant of the exponential fall to contracting Pmv(O(2)) values was accelerated in the DH running groups (Con: 14.7 +/- 1.4; DH-1: 8.9 +/- 1.4; DH-3: 8.7 +/- 1.4 s, both P < 0.05 vs. Con). These findings are consistent with the presence of substantial microvascular dysfunction after downhill eccentric running, which slows the exercise hyperemic response at the onset of contractions and reduces the Pmv(O(2)) available to drive blood-muscle O(2) delivery.
Collapse
Affiliation(s)
- Yutaka Kano
- Department of Anatomy and of Physiology and Kinesiology, Kansas State University, Manhattan, 66506-5802, USA
| | | | | | | | | | | |
Collapse
|