1
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Lipoxin A4 attenuated dexamethasone-induced muscle atrophy via activation of PGC-1α/Nrf2/TFAM pathway. J Physiol Biochem 2023; 79:107-115. [PMID: 36125698 PMCID: PMC9905194 DOI: 10.1007/s13105-022-00925-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 09/07/2022] [Indexed: 02/08/2023]
Abstract
Prolonged dexamethasone (DEX) administration causes skeletal muscle atrophy through induction of both oxidative stress and mitochondrial dysfunction. Lipoxin A4 (LXA4) is a recognized antioxidant but its effect against DEX-induced muscle atrophy has not been studied yet. This study aimed to assess the potential ameliorating effect of LXA4 on DEX-induced muscle atrophy and investigate the possible involvement of the mitochondrial dynamics pathway and the redox state in this effect. Forty male rats were divided into four groups; normal control, LXA4-treated, DEX-treated, and LXA4 plus DEX-treated. At the end of the experiment, LXA4 counteracted the effect of DEX on different parameters including muscle weight, muscle strength, serum creatine kinase activity, malondialdehyde and protein carbonyl contents, Na/K-ATPase and citrate synthase activities, mitochondrial transmembrane potential, mitochondrial transcription factor (TFAM), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and nuclear factor erythroid 2-related factor 2 (Nrf2). These findings signify the promising therapeutic effect of LXA4 against DEX-induced skeletal muscle atrophy and indicate the possible involvement of LXA4-induced mitochondrial activation in addition to its well-known antioxidant effects.
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2
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Huang H, Xue J, Zheng J, Tian H, Fang Y, Wang W, Wang G, Hou D, Lin J. Bioinformatic analysis of the gene expression profile in muscle atrophy after spinal cord injury. Sci Rep 2021; 11:21903. [PMID: 34754020 PMCID: PMC8578571 DOI: 10.1038/s41598-021-01302-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/26/2021] [Indexed: 01/13/2023] Open
Abstract
Spinal cord injury (SCI) is often accompanied by muscle atrophy; however, its underlying mechanisms remain unclear. Here, the molecular mechanisms of muscle atrophy following SCI were investigated. The GSE45550 gene expression profile of control (before SCI) and experimental (14 days following SCI) groups, consisting of Sprague–Dawley rat soleus muscle (n = 6 per group), was downloaded from the Gene Expression Omnibus database, and then differentially expressed gene (DEG) identification and Gene Ontology, pathway, pathway network, and gene signal network analyses were performed. A total of 925 differentially expressed genes, 149 biological processes, and 55 pathways were screened. In the pathway network analysis, the 10 most important pathways were citrate cycle (TCA cycle), pyruvate metabolism, MAPK signalling pathway, fatty acid degradation, propanoate metabolism, apoptosis, focal adhesion, synthesis and degradation of ketone bodies, Wnt signalling, and cancer pathways. In the gene signal network analysis, the 10 most important genes were Acat1, Acadvl, Acaa2, Hadhb, Acss1, Oxct1, Hadha, Hadh, Acaca, and Cpt1b. Thus, we screened the key genes and pathways that may be involved in muscle atrophy after SCI and provided support for finding valuable markers for this disease.
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Affiliation(s)
- Hui Huang
- Department of Sports Medicine, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China
| | - Jinju Xue
- Department of Geriatrics, Affiliated Haikou Hospital, Central South University Xiangya School of Medicine, Haikou, 570208, Hainan, China
| | - Jiaxuan Zheng
- Department of Pathology, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China
| | - Haiquan Tian
- Department of Orthopaedic Surgery, The Second People's Hospital of Changzhi, Changzhi, 046000, Shanxi, China
| | - Yehan Fang
- Department of Sports Medicine, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China
| | - Wei Wang
- Department of Emergency, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China
| | - Guangji Wang
- Department of Sports Medicine, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China
| | - Dan Hou
- Department of Neurology, Affiliated Haikou Hospital, Central South University Xiangya School of Medicine, Haikou, 570208, Hainan, China.
| | - Jianping Lin
- Department of Joint Surgery, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), Haikou, 570311, Hainan, China.
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3
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Wan Q, Zhang L, Huang Z, Zhang H, Gu J, Xu H, Yang X, Shen Y, Law BYK, Zhu J, Sun H. Aspirin alleviates denervation-induced muscle atrophy via regulating the Sirt1/PGC-1α axis and STAT3 signaling. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1524. [PMID: 33313269 PMCID: PMC7729378 DOI: 10.21037/atm-20-5460] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Background Our prior studies have shown that inflammation may play an important triggering role during the process of denervated muscle atrophy. The nonsteroidal anti-inflammatory drug aspirin exhibits the effect of anti-inflammatory factors. This study will investigate the protective effect of aspirin on denervated muscle atrophy and the underlying mechanism. Methods Mouse models of denervated muscle atrophy were established. The protective effect of aspirin (20 mg/kg/d, i.p.) on denervated muscle atrophy was analyzed using the wet weight ratio of tibialis anterior (TA) muscle and muscle fiber cross-sectional area (CSA). The levels of inflammatory factors were detected using quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Sirtuins1 (SIRT1)/Peroxisome Proliferator-Activated Receptor γ Co-Activator 1α (PGC-1α) and Signal transducer and activator of transcription 3 (STAT3) signaling pathway and the muscle fiber type related proteins in TA muscle after denervation were analyzed by western blot assay. Results Intraperitoneal injection of aspirin (20 mg/kg/d) effectively alleviated denervation-induced muscle atrophy. This mainly manifested as follows: The wet weight ratio of TA muscle and muscle fiber CSA of mice treated with aspirin were significantly greater compared with mice treated with normal saline. The level of myosin heavy chain (MHC) increased, and the levels of muscle specific E3 ubiquitin ligase Muscle-specific RING finger-1 (MuRF-1) and muscle atrophy F-box (MAFbx) were decreased. Mitochondrial vacuolation and autophagy were inhibited, as evidenced by reduced level of autophagy related proteins PINK1, BNIP3, LC3B and Atg7 in mice treated with aspirin compared with mice treated with saline. In addition, aspirin treatment inhibited the slow-to-fast twitch muscle fiber conversion, which were related with triggering the expression of Sirt1 and PGC-1α. Moreover, aspirin reduced the levels of inflammatory factors interleukin-6, interleukin-1β and tumor necrosis factor-α and decreased the activation of STAT3 signaling pathway. Conclusions This is the first study to find that aspirin can alleviate denervation-induced muscle atrophy and inhibit the type I-to-type II muscle fiber conversion and mitophagy possibly through regulating the STAT3 inflammatory signaling pathway and Sirt1/PGC-1α signal axis. This study expands our knowledge regarding the pharmacological function of aspirin and provides a novel strategy for prevention and treatment of denervated muscle atrophy.
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Affiliation(s)
- Qiuxian Wan
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Department of Medical Laboratory, School of Public Health, Nantong University, Nantong, China
| | - Lilei Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Ziwei Huang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Haiyan Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Department of Medical Laboratory, School of Public Health, Nantong University, Nantong, China
| | - Jing Gu
- Department of Medical Laboratory, School of Public Health, Nantong University, Nantong, China
| | - Hua Xu
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, China
| | - Xiaoming Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Betty Yuen-Kwan Law
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Jianwei Zhu
- Department of Orthopedics, Affiliated Hospital of Nantong University, Nantong, China
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, China
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4
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Theilen NT, Kunkel GH, Tyagi SC. The Role of Exercise and TFAM in Preventing Skeletal Muscle Atrophy. J Cell Physiol 2017; 232:2348-2358. [PMID: 27966783 DOI: 10.1002/jcp.25737] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 12/31/2022]
Abstract
Skeletal muscle atrophy is the consequence of protein degradation exceeding protein synthesis. This arises for a multitude of reasons including the unloading of muscle during microgravity, post-surgery bedrest, immobilization of a limb after injury, and overall disuse of the musculature. The development of therapies prior to skeletal muscle atrophy settings to diminish protein degradation is scarce. Mitochondrial dysfunction is associated with skeletal muscle atrophy and contributes to the induction of protein degradation and cell apoptosis through increased levels of ROS observed with the loss of organelle function. ROS binds mtDNA, leading to its degradation and decreasing functionality. Mitochondrial transcription factor A (TFAM) will bind and coat mtDNA, protecting it from ROS and degradation while increasing mitochondrial function. Exercise stimulates cell signaling pathways that converge on and increase PGC-1α, a well-known activator of the transcription of TFAM and mitochondrial biogenesis. Therefore, in the present review we are proposing, separately, exercise and TFAM treatments prior to atrophic settings (muscle unloading or disuse) alleviate skeletal muscle atrophy through enhanced mitochondrial adaptations and function. Additionally, we hypothesize the combination of exercise and TFAM leads to a synergistic effect in targeting mitochondrial function to prevent skeletal muscle atrophy. J. Cell. Physiol. 232: 2348-2358, 2017. © 2016 The Authors. Journal of Cellular Physiology Published by © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nicholas T Theilen
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - George H Kunkel
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky
| | - Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky
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5
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Malavaki CJ, Sakkas GK, Mitrou GI, Kalyva A, Stefanidis I, Myburgh KH, Karatzaferi C. Skeletal muscle atrophy: disease-induced mechanisms may mask disuse atrophy. J Muscle Res Cell Motil 2016; 36:405-21. [DOI: 10.1007/s10974-015-9439-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 12/08/2015] [Indexed: 01/07/2023]
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6
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Abstract
Reduction of lean mass is a primary body composition change associated with aging. Because many factors contribute to lean mass reduction, the problem has been given various names depending on the proposed cause, such as "age-related sarcopenia," "dynapenia," "myopenia," "sarcopenic obesity," or simply "sarcopenia." There is currently no consensus on how to best diagnose the reduction of lean mass and its consequences on health. We propose that simple body composition methods can be used to indirectly evaluate sarcopenia, provided that those techniques are validated against the "quality of lean" criterion that associates muscle mass and metabolic function with the components of fat-free mass. Promising field methods include the use of stable isotopes for the evaluation of water compartments and new approaches to bioelectrical impedance analysis, which is also associated with the monitoring of water homeostasis.
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Affiliation(s)
- Sandra M. L. Ribeiro
- School of Arts, Sciences, and Humanities, University of São Paulo, São Paulo, Brazil; and,Body Composition Laboratory, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA
| | - Joseph J. Kehayias
- Body Composition Laboratory, USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA,To whom correspondence should be addressed. E-mail:
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7
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Wei J, Liang BS. PPM1B and P-IKKβ expression levels correlated inversely with rat gastrocnemius atrophy after denervation. Braz J Med Biol Res 2012; 45:711-5. [PMID: 22584641 PMCID: PMC3854238 DOI: 10.1590/s0100-879x2012007500080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 05/03/2012] [Indexed: 11/22/2022] Open
Abstract
Activated inhibitor of nuclear factor-κB kinase β (IKKβ) is necessary and sufficient for denervated skeletal muscle atrophy. Although several studies have shown that Mg(2+)/Mn(2+)-dependent protein phosphatase 1B (PPM1B) inactivated IKKβ, few studies have investigated the role of PPM1B in denervated skeletal muscle. In this study, we aim to explore the expression and significance of PPM1B and phosphorylated IKKβ (P-IKKβ) during atrophy of the denervated gastrocnemius. Thirty young adult female Wistar rats were subjected to right sciatic nerve transection and were sacrificed at 0 (control), 2, 7, 14, and 28 days after denervation surgery. The gastrocnemius was removed from both the denervated and the contralateral limb. The muscle wet weight ratio was calculated as the ratio of the wet weight of the denervated gastrocnemius to that of the contralateral gastrocnemius. RT-PCR and Western blot analysis showed that mRNA and protein levels of PPM1B were significantly lower than those of the control group at different times after the initiation of denervation, while P-IKKβ showed the opposite trends. PPM1B protein expression persistently decreased while P-IKKβ expression persistently increased for 28 days after denervation. PPM1B expression correlated negatively with P-IKKβ expression by the Spearman test, whereas decreasing PPM1B expression correlated positively with the muscle wet weight ratio. The expression levels of PPM1B and P-IKKβ were closely associated with atrophy in skeletal denervated muscle. These results suggest that PPM1B and P-IKKβ could be markers in skeletal muscle atrophy.
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Affiliation(s)
- Jian Wei
- Department of Orthopedics, the Second Hospital, Shanxi Medical University, Taiyuan, China
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8
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Treatment of Adolescent Idiopathic Scoliosis With Quantified Trunk Rotational Strength Training. ACTA ACUST UNITED AC 2008; 21:349-58. [DOI: 10.1097/bsd.0b013e318145b7e9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Abstract
Functional ageing processes are characterized by a loss of performance capabilities regarding coordination, flexibility, strength, speed, and endurance. The effects of ageing processes on the cardiovascular system and skeletal muscle are the foci of attention. After age 30, the maximum aerobic dynamic performance capacity decreases by an average of 8% per decade. The causes are mainly a reduction in the maximum cardiac output and decreases in capillarization and in the skeletal muscle mass. An improvement in the maximum oxygen uptake by 18% and in the aerobic-anaerobic threshold by 22% was achieved in untrained men aged 55-70 years, in a 12-week-long bicycle ergometer-training programme. The strength of the skeletal muscle decreases particularly after 50-60 years of age. The main cause is the reduction in the number of motor units and muscle fibres. Further, modifications of the endothelial function and the development of sarcopenia are of particular importance in ageing processes. General aerobic dynamic training can improve the endothelial function in old age and thus help prevent cardiovascular diseases. Strength training is most appropriate for the prevention of sarcopenia. Imaging techniques over the last 20 years have provided new findings on the influence and the significance of physical activity on the brain. We call this new interdisciplinary area 'Exercise Neuroscience'. Demands on coordination and aerobic dynamic endurance are suitable in counteracting age-related neuronal cellular loss, synapsis hypotrophy, and in improving neurogenesis and capillarization. Adjusted physical activity is thus capable of counteracting age-related changes and performance loss not only in the cardiovascular system but also in the brain.
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10
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Muscle-Specific PPARbeta/delta Agonism May Provide Synergistic Benefits with Life Style Modifications. PPAR Res 2008; 2007:30578. [PMID: 18274626 PMCID: PMC2220041 DOI: 10.1155/2007/30578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 08/08/2007] [Accepted: 11/13/2007] [Indexed: 11/26/2022] Open
Abstract
Peroxisome proliferator-activated receptor β/δ
(PPARβ/δ)
has emerged as a powerful metabolic regulator in diverse tissues
including fat, skeletal muscle, and the heart. It is now
established that activation of
PPARβ/δ
promotes fatty acid oxidation in several tissues, such as skeletal
muscle and adipose tissue. In muscle,
PPARβ/δ
appears to act as a central regulator of fatty acid catabolism.
PPARβ/δ contents are increased in muscle during physiological situations
such as physical exercise or long-term fasting, characterized by
increased fatty acid oxidation. Targeted expression of an
activated form of PPARβ/δ
in skeletal muscle induces a switch to form increased numbers of
type I muscle fibers resembling the fiber type transition by
endurance training. Activation of
PPARβ/δ
also enhances mitochondrial capacity and fat oxidation in the
skeletal muscle that resembles the effect of regular exercise.
Therefore, it is hypothesized that muscle-specific
PPARβ/δ
agonists could be a key strategy to support the poor
cardiorespiratory fitness associated with metabolic disorders.
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11
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Gomes ARS, Cornachione A, Salvini TF, Mattiello-Sverzut AC. Morphological effects of two protocols of passive stretch over the immobilized rat soleus muscle. J Anat 2007; 210:328-35. [PMID: 17331181 PMCID: PMC2100284 DOI: 10.1111/j.1469-7580.2007.00697.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
This study evaluated two different stretching protocols employed during a period of hind-limb immobilization in terms of their effects on muscle morphology. Quantitative data regarding the soleus muscle were obtained based on the clinical hypothesis that a high frequency of this exercise would improve the recovery of muscle structure. Twenty-four male Wistar rats were divided into four groups (n = 6 each): the control group (C); the immobilized group, in which the left hind limb was immobilized in order to maintain the soleus muscle in a fully shortened position for 3 weeks (I); the 'immobilized and stretched every 3 days' group, in which the left hind limb was immobilized as in the immobilized group, but with the soleus muscle stretched every 3 days for 40 min (Ist3); and the 'immobilized (as in the immobilized group) and stretched every 7 days' group (ISt7). All soleus muscles were excised 21 days after the beginning of the experiment, and were processed for (1) haematoxylin and eosin and myosin ATPase to evaluate muscle morphology and cross-sectional area and the proportions of the different fibre types, and (2) ultrastructural analysis. The cross-sectional area was found to have decreased in all fibre types (I, II and C), mainly in ISt7, when compared with the C group and ISt3 group. The proportion of the different fibre types did not show statistical difference between groups. Light and electron microscopy examination revealed signs of cell degeneration that was more intense in the group immobilized and stretched three times a week. In conclusion, sessions of passive stretching applied to the soleus during immobilization induce muscle fibre injury, suggesting that this therapeutic tool should be applied carefully to disused muscles.
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Affiliation(s)
- Anna R S Gomes
- Unit of Skeletal Muscle Plasticity, Physical Therapy Department, Federal University of São CarlosBrazil
| | - Anabelle Cornachione
- Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São PauloSP, Brazil
| | - Tania F Salvini
- Unit of Skeletal Muscle Plasticity, Physical Therapy Department, Federal University of São CarlosBrazil
| | - Ana Cláudia Mattiello-Sverzut
- Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Ribeirão Preto School of Medicine, University of São PauloSP, Brazil
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12
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Ryall JG, Sillence MN, Lynch GS. Systemic administration of beta2-adrenoceptor agonists, formoterol and salmeterol, elicit skeletal muscle hypertrophy in rats at micromolar doses. Br J Pharmacol 2006; 147:587-95. [PMID: 16432501 PMCID: PMC1751341 DOI: 10.1038/sj.bjp.0706669] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
beta(2)-Adrenoceptor agonists provide a potential therapy for muscle wasting and weakness, but their use may be limited by adverse effects on the heart, mediated in part, by beta(1)-adrenoceptor activation. Two beta(2)-agonists, formoterol and salmeterol, are approved for treating asthma and have an extended duration of action and increased safety, associated with greater beta(2)-adrenoceptor selectivity. The pharmacological profiles of formoterol and salmeterol and their effects on skeletal and cardiac muscle mass were investigated in 12-week-old, male F344 rats. Formoterol and salmeterol were each administered via daily i.p. injection at one of seven doses (ranging from 1 to 2,000 microg kg(-1) day(-1)), for 4 weeks. Rats were anaesthetised and the EDL and soleus muscles and the heart were excised and weighed. Dose-response curves were constructed based on skeletal and cardiac muscle hypertrophy. Formoterol was more potent than salmeterol, with a significantly lower ED(50) in EDL muscles (1 and 130 microg kg(-1) day(-1), P <0.05), whereas salmeterol had greater intrinsic activity than formoterol in both EDL and soleus muscles (12% greater hypertrophy than formoterol). The drugs had similar potency and intrinsic activity in the heart, with a smaller leftward shift for formoterol than seen in skeletal muscle. A dose of 25 microg kg(-1) day(-1) of formoterol elicited greater EDL and soleus hypertrophy than salmeterol, but resulted in similar beta-adrenoceptor downregulation. These results show that doses as low as 1 microg kg(-1) day(-1) of formoterol can elicit significant muscle hypertrophy with minimal cardiac hypertrophy and provide important information regarding the potential therapeutic use of formoterol and salmeterol for muscle wasting.
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MESH Headings
- Adrenergic beta-2 Receptor Agonists
- Adrenergic beta-Agonists/administration & dosage
- Adrenergic beta-Agonists/pharmacology
- Albuterol/administration & dosage
- Albuterol/analogs & derivatives
- Albuterol/pharmacology
- Animals
- Cardiomegaly/chemically induced
- Dose-Response Relationship, Drug
- Down-Regulation
- Ethanolamines/administration & dosage
- Ethanolamines/pharmacology
- Formoterol Fumarate
- Heart/drug effects
- Male
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle Fibers, Slow-Twitch/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myocardium/metabolism
- Myocardium/pathology
- Rats
- Rats, Inbred F344
- Receptors, Adrenergic, beta-2/metabolism
- Salmeterol Xinafoate
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Affiliation(s)
- James G Ryall
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Grattan Street, Victoria 3010, Australia
| | - Martin N Sillence
- School of Agricultural and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2678, Australia
| | - Gordon S Lynch
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Grattan Street, Victoria 3010, Australia
- Author for correspondence:
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13
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Brack AS, Bildsoe H, Hughes SM. Evidence that satellite cell decrement contributes to preferential decline in nuclear number from large fibres during murine age-related muscle atrophy. J Cell Sci 2006; 118:4813-21. [PMID: 16219688 DOI: 10.1242/jcs.02602] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Skeletal muscle fibres are multinucleate syncitial cells that change size during adult life depending on functional demand. The relative contribution of change in nuclear number and/or cell growth to fibre size change is unclear. We report that nuclei/unit length decreases in larger fibres during skeletal muscle ageing. This leads to an increased size of nuclear domain (quantity of cytoplasm/number of nuclei within that cytoplasm). Initially, larger fibres have more satellite cells than small fibres, but this advantage is lost as satellite cells decline with age. These changes are accompanied by an overall decline in fibre size, returning domain size to the normal range. Exacerbated loss of fibre nuclei per unit length during ageing of myoD-null mice provides the first experimental support for the hypothesis that a satellite cell defect causes inadequate nuclear replacement. We propose a model in which a decline in satellite cell function and/or number during ageing leads to a loss of nuclei from large fibres and an associated domain size increase that triggers cytoplasmic atrophy through the normal cell-size-regulating machinery.
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Affiliation(s)
- Andrew S Brack
- MRC Centre for Developmental Neurobiology and Randall Division for Cell and Molecular Biophysics, New Hunt's House, King's College London, London, SE1 1UL, UK
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14
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Ramsey MM, Adams MM, Ariwodola OJ, Sonntag WE, Weiner JL. Functional characterization of des-IGF-1 action at excitatory synapses in the CA1 region of rat hippocampus. J Neurophysiol 2005; 94:247-54. [PMID: 15985695 DOI: 10.1152/jn.00768.2004] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Insulin-like growth factor-1 (IGF-1) and growth hormone play a major role in the growth and development of tissues throughout the mammalian body. Plasma IGF-1 concentrations peak during puberty and decline with age. We have determined that chronic treatments to restore plasma IGF-1 concentrations to adult levels attenuate spatial learning deficits in aged rats, but little is known of the acute actions of IGF-1 in the brain. To this end, we utilized hippocampal slices from young Sprague-Dawley rats to characterize the acute effects of des-IGF-1 on excitatory synaptic transmission in the CA1 region. We observed a 40% increase in field excitatory postsynaptic potential (fEPSP) slope with application of des-IGF-1 (40 ng/ml) and used whole cell patch-clamp recordings to determine that this enhancement was due to a postsynaptic mechanism involving alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate (AMPA) but not N-methyl-D-aspartate receptors. Furthermore, the enhancement was completely blocked by the broad-spectrum tyrosine kinase inhibitor, genistein (220 microM), and significantly reduced by the PI3K blockers wortmannin (1 microM) and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (10 microM), suggesting that the effect was predominantly dependent on PI3K activation. This characterization of the acute actions of des-IGF-1 at hippocampal excitatory synapses may provide insight into the mechanism by which long-term increases in plasma IGF-1 impart cognitive benefits in aged rats. Increases in AMPA receptor-mediated synaptic transmission may contribute directly to cognitive improvement or initiate long-term changes in synthesis of proteins such as brain-derived neurotrophic factor that are important to learning and memory.
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Affiliation(s)
- Melinda M Ramsey
- Department of Physiology, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina 27157-1083, USA
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Bamman MM, Ragan RC, Kim JS, Cross JM, Hill VJ, Tuggle SC, Allman RM. Myogenic protein expression before and after resistance loading in 26- and 64-yr-old men and women. J Appl Physiol (1985) 2004; 97:1329-37. [PMID: 15155718 DOI: 10.1152/japplphysiol.01387.2003] [Citation(s) in RCA: 64] [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
Based on the growing body of evidence implicating an important role for myogenic regulatory factors (MRFs) in the adaptive responses of skeletal muscle to mechanical load, we tested the hypothesis that protein concentrations of MRFs as well as cell cycle proteins (i.e., cyclins and cyclin-dependent kinase inhibitors) would be altered after heavy leg resistance exercise (RE). Because we and others, however, have shown a blunted adaptive response to long-term resistance training in older (O) women [females (F)] compared with men (M), we also tested the hypothesis that these myogenic responses to RE would be influenced by age and gender. Twenty-two younger (Y) adults (20-35 yr, 11 YF, 11 YM) and 20 O adults (60-75 yr, 9 OF, 11 OM) consented to vastus lateralis muscle biopsy before and 24 h after a bout of RE using a regimen known to induce myofiber hypertrophy when performed 2-3 days/wk for several weeks (3 sets of 80% one-repetition maximum for squat, leg press, and knee extension). Protein concentrations of MRFs (MyoD, myogenin, myf-6), cyclin D1, cyclin B1, alpha-actin, and the cyclin-dependent kinase inhibitor p27kip were determined by immunoblotting. Data were analyzed by using age x gender x load repeated-measures ANOVA. Myogenin expression was 44% higher (P <0.05) in O compared with Y, and myf-6 tended to be higher in OF compared with YF (95%, P=0.059). A significant gender x load interaction indicated that, in F, RE led to a reduction in p27kip (20%; P<0.05), which was driven mainly by a 27% drop in OF. Levels of cyclin D1, cyclin B1, MyoD, myf-6, and alpha-actin were not influenced by age, gender, or loading. We report a novel finding in humans of markedly higher myogenin protein content in older sedentary muscle. The results do not, however, support the hypothesis that myogenic protein expression is altered 24 h after RE, irrespective of age or gender. Although the time point of postexercise muscle biopsy could be viewed as too early to capture maximal effects for most of these proteins, the significant decline in p27kip concentration found in OF suggests that mechanical load may provide one means of overcoming the inhibitory influence of p27kip.
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Affiliation(s)
- Marcas M Bamman
- UAB Dept. of Physiology and Biophysics, Muscle Research Laboratory, GRECC/11G, Veterans Affairs Medical Center, 1530 3rd Ave. South, Birmingham, AL 35294-0001, USA.
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