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Ojima K, Kigaki M, Ichimura E, Suzuki T, Kobayashi K, Muroya S, Nishimura T. Endogenous slow and fast myosin dynamics in myofibers isolated from mice expressing GFP-Myh7 and Kusabira Orange-Myh1. Am J Physiol Cell Physiol 2022; 323:C520-C535. [PMID: 35759444 DOI: 10.1152/ajpcell.00415.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Skeletal muscle consists of slow and fast myofibers in which different myosin isoforms are expressed. Approximately 300 myosins form a single thick filament in the myofibrils, where myosin is continuously exchanged. However, endogenous slow and fast myosin dynamics have not been fully understood. To elucidate those dynamics, here we generated mice expressing green fluorescence protein-tagged slow myosin heavy chain (GFP-Myh7) and Kusabira Orange fluorescence protein-tagged fast myosin heavy chain (KuO-Myh1). First, these mice enabled us to distinguish between GFP- and KuO-myofibers under fluorescence microscopy: GFP-Myh7 and KuO-Myh1 were exclusively expressed in slow myofibers and fast myofibers, respectively. Next, to monitor endogenous myosin dynamics, fluorescence recovery after photobleaching (FRAP) was conducted. The mobile fraction (Mf) of GFP-Myh7 and that of KuO-Myh1 were almost constant values independent of the regions of the myofibers and the muscle portions where the myofibers were isolated. Intriguingly, proteasome inhibitor treatment significantly decreased the Mf in GFP-Myh7 but not in KuO-Myh1 myofibers, indicating that the response to a disturbance in protein turnover depended on muscle fiber type. Taken together, the present results indicated that the mice we generated are promising tools not only for distinguishing between GFP- and KuO-myofibers but also for studying the dynamics of endogenous myosin isoforms by live-cell fluorescence imaging.
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Affiliation(s)
- Koichi Ojima
- Muscle Biology Research Unit, Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, Japan
| | - Masahiro Kigaki
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Emi Ichimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Takahiro Suzuki
- Laboratory of Muscle and Meat Science, Department of Animal and Marine Bioresource Sciences, Faculty of Agriculture, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan
| | - Ken Kobayashi
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Susumu Muroya
- Muscle Biology Research Unit, Division of Animal Products Research, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, Japan
| | - Takanori Nishimura
- Research Faculty of Agriculture, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan
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2
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Takahashi K, Kitaoka Y, Matsunaga Y, Hatta H. Lactate administration does not affect denervation-induced loss of mitochondrial content and muscle mass in mice. FEBS Open Bio 2021; 11:2836-2844. [PMID: 34510821 PMCID: PMC8487050 DOI: 10.1002/2211-5463.13293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/24/2021] [Accepted: 09/08/2021] [Indexed: 01/01/2023] Open
Abstract
Lactate is considered to be a signaling molecule that induces mitochondrial adaptation and muscle hypertrophy. The purpose of this study was to examine whether lactate administration attenuates denervation-induced loss of mitochondrial content and muscle mass. Eight-week-old male Institute of Cancer Research mice underwent unilateral sciatic nerve transection surgery. The contralateral hindlimb served as a sham-operated control. From the day of surgery, mice were injected intraperitoneally with PBS or sodium lactate (equivalent to 1 g·kg-1 body weight) once daily for 9 days. After 10 days of denervation, gastrocnemius muscle weight decreased to a similar extent in both the PBS- and lactate-injected groups. Denervation significantly decreased mitochondrial enzyme activity, protein content, and MCT4 protein content in the gastrocnemius muscle. However, lactate administration did not have any significant effects. The current observations suggest that daily lactate administration for 9 days does not affect denervation-induced loss of mitochondrial content and muscle mass.
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Affiliation(s)
- Kenya Takahashi
- Department of Sports SciencesThe University of TokyoMeguro‐kuJapan
| | - Yu Kitaoka
- Department of Human SciencesKanagawa UniversityYokohamaJapan
| | - Yutaka Matsunaga
- Department of Sports SciencesThe University of TokyoMeguro‐kuJapan
| | - Hideo Hatta
- Department of Sports SciencesThe University of TokyoMeguro‐kuJapan
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3
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Coq JO, Delcour M, Ogawa Y, Peyronnet J, Castets F, Turle-Lorenzo N, Montel V, Bodineau L, Cardot P, Brocard C, Liabeuf S, Bastide B, Canu MH, Tsuji M, Cayetanot F. Mild Intrauterine Hypoperfusion Leads to Lumbar and Cortical Hyperexcitability, Spasticity, and Muscle Dysfunctions in Rats: Implications for Prematurity. Front Neurol 2018; 9:423. [PMID: 29973904 PMCID: PMC6020763 DOI: 10.3389/fneur.2018.00423] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/22/2018] [Indexed: 12/22/2022] Open
Abstract
Intrauterine ischemia-hypoxia is detrimental to the developing brain and leads to white matter injury (WMI), encephalopathy of prematurity (EP), and often to cerebral palsy (CP), but the related pathophysiological mechanisms remain unclear. In prior studies, we used mild intrauterine hypoperfusion (MIUH) in rats to successfully reproduce the diversity of clinical signs of EP, and some CP symptoms. Briefly, MIUH led to inflammatory processes, diffuse gray and WMI, minor locomotor deficits, musculoskeletal pathologies, neuroanatomical and functional disorganization of the primary somatosensory and motor cortices, delayed sensorimotor reflexes, spontaneous hyperactivity, deficits in sensory information processing, memory and learning impairments. In the present study, we investigated the early and long-lasting mechanisms of pathophysiology that may be responsible for the various symptoms induced by MIUH. We found early hyperreflexia, spasticity and reduced expression of KCC2 (a chloride cotransporter that regulates chloride homeostasis and cell excitability). Adult MIUH rats exhibited changes in muscle contractile properties and phenotype, enduring hyperreflexia and spasticity, as well as hyperexcitability in the sensorimotor cortex. Taken together, these results show that reduced expression of KCC2, lumbar hyperreflexia, spasticity, altered properties of the soleus muscle, as well as cortical hyperexcitability may likely interplay into a self-perpetuating cycle, leading to the emergence, and persistence of neurodevelopmental disorders (NDD) in EP and CP, such as sensorimotor impairments, and probably hyperactivity, attention, and learning disorders.
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Affiliation(s)
- Jacques-Olivier Coq
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France.,Centre National de la Recherche Scientifique, Neurosciences Intégratives et Adaptatives, UMR 7260, Aix Marseille Université, Marseille, France
| | - Maxime Delcour
- Centre National de la Recherche Scientifique, Neurosciences Intégratives et Adaptatives, UMR 7260, Aix Marseille Université, Marseille, France
| | - Yuko Ogawa
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Julie Peyronnet
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Francis Castets
- Centre National de la Recherche Scientifique, Institut de Biologie du Développement de Marseille, UMR 7288, Aix-Marseille Université, Marseille, France
| | - Nathalie Turle-Lorenzo
- FR 3512 Fédération 3C, Aix Marseille Université - Centre National de la Recherche Scientifique, Marseille, France
| | - Valérie Montel
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Laurence Bodineau
- Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Phillipe Cardot
- Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
| | - Cécile Brocard
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Sylvie Liabeuf
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France
| | - Bruno Bastide
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Marie-Hélène Canu
- EA 7369 ≪Activité Physique, Muscle et Santé≫ - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Université de Lille, Lille, France
| | - Masahiro Tsuji
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Florence Cayetanot
- Centre National de la Recherche Scientifique, Institut de Neurosciences de la Timone, UMR 7289, Aix Marseille Université, Marseille, France.,Institut National de la Santé et de la Recherche Médicale, UMR_S1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Paris, France
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4
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Valle G, Vergani B, Sacchetto R, Reggiani C, De Rosa E, Maccatrozzo L, Nori A, Villa A, Volpe P. Characterization of fast-twitch and slow-twitch skeletal muscles of calsequestrin 2 (CASQ2)-knock out mice: unexpected adaptive changes of fast-twitch muscles only. J Muscle Res Cell Motil 2017; 37:225-233. [PMID: 28130614 DOI: 10.1007/s10974-016-9463-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 12/22/2016] [Indexed: 01/02/2023]
Abstract
This study investigates the functional role of calsequestrin 2 (CASQ2) in both fast-twitch and slow-twitch skeletal muscles by using CASQ2-/- mice; CASQ2 is expressed throughout life in slow-twitch muscles, but only in the developmental and neonatal stages in fast-twitch muscles. CASQ2-/- causes increase in calsequestrin 1 (CASQ1) expression, but without functional changes in both muscle types. CASQ2-/- mice have ultrastructural changes in fast-twitch muscles only, i.e., formation of pentads and stacks in the sarcoplasmic reticulum.
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Affiliation(s)
- Giorgia Valle
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Barbara Vergani
- Consorzio MIA (Microscopy Image Analysis), Università di Milano-Bicocca, 20052, Monza, Italy
| | - Roberta Sacchetto
- Dipartimento di Biomedicina Comparata ed Alimentazione dell'Università di Padova, Padova, Italy
| | - Carlo Reggiani
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Edith De Rosa
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Lisa Maccatrozzo
- Dipartimento di Biomedicina Comparata ed Alimentazione dell'Università di Padova, Padova, Italy
| | - Alessandra Nori
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy
| | - Antonello Villa
- Consorzio MIA (Microscopy Image Analysis), Università di Milano-Bicocca, 20052, Monza, Italy
| | - Pompeo Volpe
- Dipartimento di Scienze Biomediche dell'Università di Padova, Istituto Interuniversitario di Miologia, Viale G. Colombo 3, 35121, Padova, Italy.
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5
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Matsumoto Y, Nakano J, Oga S, Kataoka H, Honda Y, Sakamoto J, Okita M. The non-thermal effects of pulsed ultrasound irradiation on the development of disuse muscle atrophy in rat gastrocnemius muscle. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:1578-1586. [PMID: 24613643 DOI: 10.1016/j.ultrasmedbio.2013.12.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 12/10/2013] [Accepted: 12/31/2013] [Indexed: 06/03/2023]
Abstract
This study examined the effects of therapeutic pulsed ultrasound (US) on the development of disuse muscle atrophy in rat gastrocnemius muscle. Male Wistar rats were randomly distributed into control, immobilization (Im), sham US, and US groups. In the Im, sham US and US groups, the bilateral ankle joints of each rat were immobilized in full plantar flexion with a plaster cast for a 4-wk period. The pulsed US (frequency, 1 MHz; intensity, 1.0 W/cm(2); pulsed mode 1:4; 15 min) was irradiated to the gastrocnemius muscle in the US group over a 4-wk immobilization period. The pulsed US irradiation delivered only non-thermal effects to the muscle. In conjunction with US irradiation, 5-bromo-2'-deoxyuridine (BrdU) was injected subcutaneously to label the nuclei of proliferating satellite cells 1 h before each pulsed US irradiation. Immobilization resulted in significant decreases in the mean diameters of type I, IIA and IIB muscle fibers of the gastrocnemius muscle in the Im, sham US and US groups compared with the control group. However, the degrees of muscle fiber atrophy for all types were significantly lower in the US group compared with the Im and sham US groups. Although the number of capillaries and the concentrations of insulin-like growth factor and basic fibroblast growth factor did not change in the muscle, the number of BrdU-positive nuclei in the muscle was significantly increased by pulsed US irradiation in the US group. The results of this study suggest that pulsed US irradiation inhibits the development of disuse muscle atrophy partly via activation of satellite cells.
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Affiliation(s)
- Yoko Matsumoto
- Department of Rehabilitation, Saiseikai Nagasaki Hospital, Nagasaki, Japan
| | - Jiro Nakano
- Unit of Physical and Occupational Therapy, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
| | - Satoshi Oga
- Department of Rehabilitation, Saiseikai Nagasaki Hospital, Nagasaki, Japan
| | - Hideki Kataoka
- Department of Rehabilitation, Nagasaki Memorial Hospital, Nagasaki, Japan; Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuichiro Honda
- Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Junya Sakamoto
- Department of Rehabilitation, Nagasaki University Hospital, Nagasaki, Japan
| | - Minoru Okita
- Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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6
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Abstract
This review concentrates on the biology of long-term denervated muscle, especially as it relates to newer techniques for restoring functional mass. After denervation, muscle passes through three stages: 1) immediate loss of voluntary function and rapid loss of mass, 2) increasing atrophy and loss of sarcomeric organization, and 3) muscle fiber degeneration and replacement of muscle by fibrous connective tissue and fat. Parallel to the overall program of atrophy and degeneration is the proliferation and activation of satellite cells, and the appearance of neomyogenesis within the denervated muscle. Techniques such as functional electrical stimulation take advantage of this capability to restore functional mass to a denervated muscle.
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Affiliation(s)
- Bruce M Carlson
- Institute of Gerontology, University of Michigan , Ann Arbor, Michigan, USA
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7
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Young K, Cramp R, Franklin C. Hot and steady: Elevated temperatures do not enhance muscle disuse atrophy during prolonged aestivation in the ectothermCyclorana alboguttata. J Morphol 2012; 274:165-74. [DOI: 10.1002/jmor.20080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 08/12/2012] [Accepted: 08/22/2012] [Indexed: 01/31/2023]
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8
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Boncompagni S, Thomas M, Lopez JR, Allen PD, Yuan Q, Kranias EG, Franzini-Armstrong C, Perez CF. Triadin/Junctin double null mouse reveals a differential role for Triadin and Junctin in anchoring CASQ to the jSR and regulating Ca(2+) homeostasis. PLoS One 2012; 7:e39962. [PMID: 22768324 PMCID: PMC3388061 DOI: 10.1371/journal.pone.0039962] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 05/31/2012] [Indexed: 11/17/2022] Open
Abstract
Triadin (Tdn) and Junctin (Jct) are structurally related transmembrane proteins thought to be key mediators of structural and functional interactions between calsequestrin (CASQ) and ryanodine receptor (RyRs) at the junctional sarcoplasmic reticulum (jSR). However, the specific contribution of each protein to the jSR architecture and to excitation-contraction (e-c) coupling has not been fully established. Here, using mouse models lacking either Tdn (Tdn-null), Jct (Jct-null) or both (Tdn/Jct-null), we identify Tdn as the main component of periodically located anchors connecting CASQ to the RyR-bearing jSR membrane. Both proteins proved to be important for the structural organization of jSR cisternae and retention of CASQ within them, but with different degrees of impact. Our results also suggest that the presence of CASQ is responsible for the wide lumen of the jSR cisternae. Using Ca(2+) imaging and Ca(2+) selective microelectrodes we found that changes in e-c coupling, SR Ca(2+)content and resting [Ca(2+)] in Jct, Tdn and Tdn/Jct-null muscles are directly correlated to the effect of each deletion on CASQ content and its organization within the jSR. These data suggest that in skeletal muscle the disruption of Tdn/CASQ link has a more profound effect on jSR architecture and myoplasmic Ca(2+) regulation than Jct/CASQ association.
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Affiliation(s)
- Simona Boncompagni
- DNI-Department of Neuroscience and Imaging, CeSI-Center for Research on Ageing, University of G. D'Annunzio, Chieti, Italy.
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9
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Tomori K, Ohta Y, Nishizawa T, Tamaki H, Takekura H. Low-intensity electrical stimulation ameliorates disruption of transverse tubules and neuromuscular junctional architecture in denervated rat skeletal muscle fibers. J Muscle Res Cell Motil 2010; 31:195-205. [DOI: 10.1007/s10974-010-9223-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
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10
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Franzini-Armstrong C. RyRs: Their Disposition, Frequency, and Relationships with Other Proteins of Calcium Release Units. CURRENT TOPICS IN MEMBRANES 2010; 66:3-26. [PMID: 22353474 DOI: 10.1016/s1063-5823(10)66001-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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11
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Imagita H, Yamano S, Tobimatsu Y, Miyata H. Age-related changes in contraction and relaxation of rat diaphragm. ACTA ACUST UNITED AC 2010; 30:337-42. [PMID: 20051642 DOI: 10.2220/biomedres.30.337] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Age-related changes of physiological and biochemical properties were examined in the diaphragm muscle, which has particularly high activation compared to that of other skeletal muscles. The diaphragm from 10-week-, 50-week- and 100-week-old male Wistar rats were used to measure in vitro isometric contractile properties, sarcoplasmic reticulum (SR) Ca2+-ATPase activity, and myosin heavy chain (MHC) isoform composition. Although there were no significant differences in specific twitch tension of the diaphragm among the groups, there was significant reduction in specific tetanic tension in the 50-week to 100-week groups. The contraction time and 1/2 relaxation time of twitch contraction extended with aging, and significant differences were found between 10-week-old and 100-week-old diaphragms. Regarding the activity of SR Ca2+-ATPase, the pattern of age-related change was similar to that in the 1/2 relaxation time and there was a significant difference between 10-week-old and 100-week-old diaphragms. There was a significant increase in the relative composition of the MHC I isoform in 100-week-diaphragms compared to that in 10-week-old diaphragms and a concomitant decrease in the relative composition of fast myosin was noted. These findings demonstrated that older diaphragms have slower contraction and relaxation speeds, and these alterations were attributed to changes in SR Ca2+-ATPase activity and MHC isoform composition.
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Affiliation(s)
- Hidetaka Imagita
- Department of Physical Therapy, Faculty of Health Sciences, Kio University, Nara, Japan
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12
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Yamashita S, McGrath KF, Yuki A, Tamaki H, Kasuga N, Takekura H. Assembly of transverse tubule architecture in the middle and myotendinous junctional regions in developing rat skeletal muscle fibers. J Muscle Res Cell Motil 2007; 28:141-51. [PMID: 17610135 DOI: 10.1007/s10974-007-9111-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 06/03/2007] [Indexed: 11/26/2022]
Abstract
The transverse (t)-tubule is responsible for the rapid inward spread of excitation from the sarcolemma to the inside of the muscle fiber, and the compartments of the t-tubule become highly and regularly organized during development. Although it is known that skeletal muscle fibers lengthen by adding sarcomeres at the myotendinous junction (MTJ) during development, no specific model exists for the assembly of new t-tubule architecture at the MTJ. We performed an electron-microscopic examination of the assembly of t-tubule architecture at the MTJ in developing rat skeletal muscle fibers. Although the longitudinally oriented t-tubule elements represent only a small fraction of the total t-tubule system in adult muscle fibers, they were observed at both A-band and I-band regions of middle and MTJ regions in early developmental stages, and gradually disappeared in the middle regions of muscle fibers during development; however, they remained in the MTJ even in adult muscle fibers. The frequency of pentads and heptads (two or three t-tubule elements with three or four elements of terminal cisternae, closely aligned with terminal cisternae of the sarcoplasmic reticulum) decreased during development, with sudden decrease between 7 and 10 weeks of age in the middle regions. Interestingly, although the frequency of decrease appeared to be higher in the middle region than in the MTJ regions in early (3- to 7-week) development, this pattern reversed, and the frequency of decrease was higher in the MTJ in later development (after 10 weeks of age). The MTJ maintained the features of immature membrane systems involved in e-c coupling much longer than the middle region of the fiber during development. The assembly of t-tubule architecture during postnatal development thus follows different processes in the middle and MTJ regions of skeletal muscle fibers.
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Affiliation(s)
- Susumu Yamashita
- Department of Physiological Sciences, National Institute of Fitness and Sports, 1, Shiromizu, Kanoya 891-2393 Kagoshima, Japan
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Ashley Z, Sutherland H, Lanmüller H, Russold MF, Unger E, Bijak M, Mayr W, Boncompagni S, Protasi F, Salmons S, Jarvis JC. Atrophy, but not necrosis, in rabbit skeletal muscle denervated for periods up to one year. Am J Physiol Cell Physiol 2007; 292:C440-51. [PMID: 17218372 DOI: 10.1152/ajpcell.00085.2006] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our understanding of the effects of long-term denervation on skeletal muscle is heavily influenced by an extensive literature based on the rat. We have studied physiological and morphological changes in an alternative model, the rabbit. In adult rabbits, tibialis anterior muscles were denervated unilaterally by selective section of motor branches of the common peroneal nerve and examined after 10, 36, or 51 wk. Denervation reduced muscle mass and cross-sectional area by 50-60% and tetanic force by 75%, with no apparent reduction in specific force (force per cross-sectional area of muscle fibers). The loss of mass was associated with atrophy of fast fibers and an increase in fibrous and adipose connective tissue; the diameter of slow fibers was preserved. Within fibers, electron microscopy revealed signs of ultrastructural disorganization of sarcomeres and tubular systems. This, rather than the observed transformation of fiber type from IIx to IIa, was probably responsible for the slow contractile speed of the muscles. The muscle groups denervated for 10, 36, or 51 wk showed no significant differences. At no stage was there any evidence of necrosis or regeneration, and the total number of fibers remained constant. These changes are in marked contrast to the necrotic degeneration and progressive decline in mass and force that have previously been found in long-term denervated rat muscles. The rabbit may be a better choice for a model of the effects of denervation in humans, at least up to 1 yr after lesion.
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Affiliation(s)
- Z Ashley
- Department of Human Anatomy and Cell Biology, School of Biomedical Sciences, Ashton Street, University of Liverpool, Liverpool L69 3GE, UK
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14
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Midrio M. The denervated muscle: facts and hypotheses. A historical review. Eur J Appl Physiol 2006; 98:1-21. [PMID: 16896733 DOI: 10.1007/s00421-006-0256-z] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2006] [Indexed: 01/09/2023]
Abstract
Denervation changes in skeletal muscle (atrophy; alterations of myofibrillar expression, muscle membrane electrical properties, ACh sensitivity and excitation-contraction coupling process; fibrillation), and their possible causes are reviewed. All changes can be counteracted by muscle electrostimulation, while denervation-like effects can be caused by the complete conduction block in muscle nerve. These results do not support the hypothesis that the lack of neurotrophic, non-motor factors plays a role in denervation phenomena. Instead they support the view that the lack of neuromotor discharge is the only cause of the phenomena and that neuromotor activity is an essential factor in regulating muscle properties. However, some experimental results cannot apparently be explained by the lack of neuromotor impulses, and may still suggest that neurotrophic influences exist. A hypothesis is that neurotrophic factors, too feeble to maintain a role in completely differentiated, adult muscles, can concur with neuromotor activity in the differentiation of immature, developing muscles.
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Affiliation(s)
- Menotti Midrio
- Department of Human Anatomy and Physiology, Section of Physiology, University of Padua, via Marzolo 3, Padova, Italy.
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15
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Flint PW, Li ZB, Lehar M, Saito K, Pai SI. Laryngeal muscle surface receptors identified using random phage library. Laryngoscope 2006; 115:1930-7. [PMID: 16319601 DOI: 10.1097/01.mlg.0000172273.98418.8d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The ultimate goal of this study is to improve the efficiency of gene transfer in mammalian muscle by developing targeted adenoviral vectors. Altering the tropism of viral vectors to recognize tissue specific antigens is one method to achieve this goal. This approach requires identification of cell-surface receptors and the insertion of target peptide sequences into the adenoviral fiber protein. In this study, phage biopanning was performed on cultured rat skeletal and laryngeal muscle to identify cell-surface receptors. STUDY DESIGN In vitro cell culture and in vivo animal model. METHODS M-13 Phage biopanning was used for muscle cell-surface receptor analysis on cultured rat skeletal and laryngeal muscle. Nonbinding and binding phage to cultured skeletal and laryngeal muscle were screened for muscle specific surface peptides. In vivo studies were then performed using muscle specific phage. RESULTS Skeletal muscle specific binding by the YASTNPM phage was observed by in vivo immunostaining. Phage titering demonstrated a 10(9)-fold increase in skeletal muscle binding compared with nontarget tissue. A peptide sequence (NPSQVKH) specific for laryngeal muscle yielded a 10(7)-fold increase in laryngeal muscle phage titer compared with nontarget tissue. CONCLUSIONS These results identify muscle cell-surface receptors that may be used as potential targets for genetic modification of adenovirus tropism. Moreover, phage specificity for skeletal and laryngeal muscle indicates specific muscle groups may be targeted.
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Affiliation(s)
- Paul W Flint
- Department of Otolaryngology-Head and Neck Surgery Johns Hopkins University, Baltimore, Maryland, USA.
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Li ZB, Lehar M, Samlan R, Flint PW. Proteomic analysis of rat laryngeal muscle following denervation. Proteomics 2005; 5:4764-76. [PMID: 16281258 DOI: 10.1002/pmic.200401329] [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: 11/08/2022]
Abstract
Laryngeal muscle atrophy induced by nerve injury is a major factor contributing to the disabling symptoms associated with laryngeal paralysis. Alterations of global proteins in rat laryngeal muscle following denervation were, therefore, studied using proteomic techniques. Twenty-eight adult Sprague-Dawley rats were divided into normal control and denervated groups. The thyroarytenoid (TA) muscle was excised 60 days after right recurrent laryngeal nerve was resected. Protein separation and identification were preformed using 2-DE and MALDI-MS with database search. Forty-four proteins were found to have significant alteration in expression level after denervation. The majority of these proteins (57%), most of them associated with energy metabolism, cellular proliferation and differentiation, signal transduction and stress reaction, were decreased levels of expression in denervated TA muscle. The remaining 43% of the proteins, most of them involved with protein degradation, immunoreactivity, injury repair, contraction, and microtubular formation, were found to have increased levels of expression. The protein modification sites by phosphorylation were detected in 22% of the identified proteins that presented multiple-spot patterns on 2-D gel. Significant changes in protein expression in denervated laryngeal muscle may provide potential therapeutic strategies for the treatment of laryngeal paralysis.
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Affiliation(s)
- Zhao-Bo Li
- Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Johns Hopkins University, 601 N. Caroline Street, Baltimore, MD 21287, USA
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17
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Divet A, Paesante S, Bleunven C, Anderson A, Treves S, Zorzato F. Novel sarco(endo)plasmic reticulum proteins and calcium homeostasis in striated muscles. J Muscle Res Cell Motil 2005; 26:7-12. [PMID: 16096683 DOI: 10.1007/s10974-005-9001-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Revised: 06/09/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
The impact of calcium signaling on many cellular functions is reflected by the tight regulation of the intracellular Ca(2+) concentration that is ensured by diverse pumps, channels, transporters and Ca(2+) binding proteins. In this review, we present recently identified novel sarco(endo)plasmic reticulum proteins that may have a potential involvement in the regulation of Ca(2+) homeostasis in striated muscles.
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Affiliation(s)
- A Divet
- Department of Experimental and Diagnostic Medicine, Section of General Pathology, University of Ferrara, Italy
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18
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Feriotto G, Finotti A, Volpe P, Treves S, Ferrari S, Angelelli C, Zorzato F, Gambari R. Myocyte enhancer factor 2 activates promoter sequences of the human AbetaH-J-J locus, encoding aspartyl-beta-hydroxylase, junctin, and junctate. Mol Cell Biol 2005; 25:3261-75. [PMID: 15798210 PMCID: PMC1069596 DOI: 10.1128/mcb.25.8.3261-3275.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alternative splicing of the locus AbetaH-J-J generates three functionally distinct proteins: an enzyme, AbetaH (aspartyl-beta-hydroxylase), a structural protein of the sarcoplasmic reticulum membrane (junctin), and an integral membrane calcium binding protein (junctate). Junctin and junctate are two important proteins involved in calcium regulation in eukaryotic cells. To understand the regulation of these two proteins, we identified and functionally characterized one of the two promoter sequences of the AbetaH-J-J locus. We demonstrate that the P2 promoter of the AbetaH-J-J locus contains (i) a minimal sequence localized within a region -159 bp from the transcription initiation site, which is sufficient to activate transcription of both mRNAs; (ii) sequences which bind known transcriptional factors such as those belonging to the myocyte enhancer factor 2 (MEF-2), MEF-3, and NF-kappaB protein families; and (iii) sequences bound by unknown proteins. The functional characterization of the minimal promoter in C2C12 cells and in the rat soleus muscle in vivo model indicates the existence of cis elements having positive and negative effects on transcription. In addition, our data demonstrate that in striated muscle cells the calcium-dependent transcription factor MEF-2 is crucial for the transcription activity directed by the P2 promoter. The transcription directed by the AbetaH-J-J P2 promoter is induced by high expression of MEF-2, further stimulated by calcineurin and Ca2+/calmodulin-dependent protein kinase I, and inhibited by histone deacetylase 4.
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Affiliation(s)
- Giordana Feriotto
- Biotechnology Center, Biology, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy
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19
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Takekura H, Tamaki H, Nishizawa T, Kasuga N. Plasticity of the transverse tubules following denervation and subsequent reinnervation in rat slow and fast muscle fibres. J Muscle Res Cell Motil 2004; 24:439-51. [PMID: 14677647 DOI: 10.1023/a:1027356912404] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have studied the effects of short term denervation followed by reinnervation on the ultrastructure of the membrane systems and on the content of and distribution of key proteins involved in calcium regulation of fast-twitch (FT) extensor digitorum longus (EDL) and slow-twitch (ST) soleus (SOL) muscle fibres. Ischiadic nerve freezing resulted in total lack of neuromuscular transmission for 3 days followed by a slow recovery, but no decline in twitch force elicited by direct stimulation. The latter measurements indicate no significant atrophy within this time frame. The membrane systems of skeletal muscle fibres were visualized using Ca92+)-K3Fe(CN)6-OsO4 techniques and observed using a high voltage electron microscope. [3H]nitrendipine binding was used to detect levels of dihydropyridine receptor (DHPR) expression. The Ca2+ pumping free sarcoplasmic reticulum domains were not affected by the denervation, but the Ca2+ release domains were dramatically increased, particularly in the FT-EDL muscle fibres. The increase is evidenced by a doubling up of the areas of contacts between SR and transverse (t-) tubules, so that in place of the normal triadic arrangement, pentadic and heptadic junctions, formed by multiple interacting layers of ST and t-tubules are seen. Frequency of pentads and heptads increases and declines in parallel to the denervation and reinnervation but with a delay. Immunofluorecence and electron microscopy observations show presence of DHPR and ryanodine receptor clusters at pentads and heptads junctions. A significant (P < 0.01) positive correlation between the level of [3H]nitrendipine binding component and the frequency pentads and heptads was observed in both the FT-EDL and ST-SOL muscle fibres indicating that overexpression of DHPRs accompanies the build up extra junctional contacts. The results indicate that denervation reversibly affects the domains of the membrane systems involved in excitation-contraction coupling.
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Affiliation(s)
- Hiroaki Takekura
- Department of Physiological Sciences, National Institute of Fitness and Sports, Kanoya, Kagoshima 891-2393, Japan.
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20
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Reznick AZ, Menashe O, Bar-Shai M, Coleman R, Carmeli E. Expression of matrix metalloproteinases, inhibitor, and acid phosphatase in muscles of immobilized hindlimbs of rats. Muscle Nerve 2003; 27:51-9. [PMID: 12508295 DOI: 10.1002/mus.10277] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
External fixation procedures of limb immobilization provide excellent experimental models to study mechanisms involved in muscle disuse atrophy and recovery. Female Wistar rats (7-8 months old) had their right hindlimbs immobilized by an external fixation procedure for 5, 10, 21, and 30 days. Muscle mass of the gastrocnemius and quadriceps muscles was reduced by 41-46% in comparison with contralateral nonimmobilized legs. Acid phosphatase activities were significantly increased after 21 and 30 days of hindlimb immobilization. Histochemical staining for acid phosphatase activities increased in myofibers after the external fixation and also in macrophages in the adjacent extracellular matrix. Matrix metalloproteinase (MMP-2 and MMP-9) activities assessed by gel zymography and also a tissue inhibitor of metalloproteinases (TIMP-1) assessed by Western blot were elevated in the immobilized hindlimb muscles. Our study demonstrated that metalloproteinases are expressed relatively late after limb immobilization and appear to be responsible to a large degree for degradation of the extracellular matrix in experimental disuse atrophy.
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Affiliation(s)
- Abraham Z Reznick
- Department of Anatomy and Cell Biology, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, P.O. Box 9649, Haifa 31096, Israel.
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21
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Wagatsuma A, Fujimoto K, Yamada S. Alteration in albumin level during modified muscular activity. Scand J Med Sci Sports 2002; 12:143-9. [PMID: 12135446 DOI: 10.1034/j.1600-0838.2002.120304.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We have previously reported that albumin protein is increased in the atrophied muscle induced by hindlimb immobilization. The purpose of this study was to evaluate the effects of several disuse models on albumin protein and mRNA levels in mice skeletal muscle and to investigate whether the elevated amount of albumin returns to control level by muscular activity increased by hindlimb remobilization. Western blot analysis revealed that hindlimb immobilization, denervation, and tenotomy, except for hindlimb unloading, significantly increased albumin levels in soleus muscles by 2.1-, 1.9- and 2.0-fold, respectively (P < 0.001). Immunohistochemical analysis showed that albumin protein accumulates in the widened extracellular space. Reverse transcription-polymerase chain reaction (RT-PCR) assay revealed albumin gene expression to be downregulated in all disuse models relative to control level. During hindlimb remobilization, the amounts of albumin protein appeared to remain higher level after 3 and 7 days and had returned to control level after 14 days and muscle mass, the amounts of myosin heavy chain, and actin proteins seemed to restore control levels after 21 days. These results indicate that the amount of interstitial albumin protein may be modulated by muscular activity.
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Affiliation(s)
- Akira Wagatsuma
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro, Japan
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22
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Wagatsuma A, Fujimoto K, Yamada S. Effect of treatment with nifedipine, an L-type calcium channel blocker, on muscular atrophy induced by hindlimb immobilization. Scand J Med Sci Sports 2002; 12:26-30. [PMID: 11985762 DOI: 10.1034/j.1600-0838.2002.120105.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The purpose of this study was to investigate whether the prevention of calcium influx through L-type calcium channels contributed to the attenuation of muscular atrophy induced by hindlimb immobilization (HI) in a shortened position. Mice were divided into four groups (8 mice/group): control; nifedipine; HI; and HI with nifedipine. Mice received nifedipine at a dose of 5 mg/kg one day before and during the 8 days of HI. Quantitative alterations in the amount of myosin heavy chain (MyHC) and actin proteins in the soleus muscle were analyzed using SDS-PAGE. The weight of the soleus muscle decreased significantly by 40.8% (P<0.05) and 27.0% (P<0.05) after the hindlimb immobilization in the HI and HI with nifedipine groups, respectively, when compared to that of the control or nifedipine groups. Treatment with nifedipine alone appeared to have no effect on muscle mass or the amount of myofibrillar proteins. The level of MyHC proteins decreased significantly by 25.1% (P<0.001) and 17.4% (P<0.001) in the HI and HI with nifedipine groups, respectively. The level of MyHC protein in the HI with nifedipine group was significantly greater than that of the HI group (P<0.05), although there were no significant differences in the amount of actin protein. These findings suggest that nifedipine treatment may have a beneficial effect on muscular atrophy.
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Affiliation(s)
- A Wagatsuma
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
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23
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Muto M, Wakao Y, Morimoto M, Klomkleaw W, Fuller GA, Nakayama T, Oba T, Kasashima Y, Hamlin RL, Yamaguchi M. A semi-immobilization of a partial auricle induces hypertrophy and ultrastructural alteration of cardiomyocytes. Int J Cardiol 2001; 81:189-99. [PMID: 11744136 DOI: 10.1016/s0167-5273(01)00566-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Semi-immobilization of a partial area of the ventral edge, lateral epicardium of the left auricle (ventrolateral of left auricle), by using quick adhesion glue induces moderate hypertrophy of myocytes with an average increase of 34% in cross-sectional area. Intercellular connective tissues increased, and cellular sizes varied markedly. The ultrastructure of immobilized (semi-immobilized) myocytes commonly exhibited degenerating features in myofibrils, various cytoplasmic organelles including mitochondrial cristae and sarcoplasmic reticulum (SR) were disrupted, and T-tubules disappeared. Z-line streaming and widening (hypertrophic Z-line, rod bodies) and increase of metabolic particle deposition are typical phenomena in addition to intercalated disc (Id) disorganization. The results suggest that semi-immobilization of the auricle induces hypertrophy of myocytes in association with degeneration and disruption of myofibrils and other cytoplasmic organelles, and an increase of intercellular connective tissues, rather than increase of myofibril mass. This is the first study to immobilize only a part of the heart rather than the whole animal. Our results using artificial immobilization of cardiac myocytes were extremely significant since the structural alterations obtained were similar to that observed in cardiomyopathies. This suggests that myocytes progressing to heart failure are also subjected to inhibition of movement. Therefore, this experiment may prove very useful as a model for studying the functional effect of heart failure observed in cardiomyopathy.
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Affiliation(s)
- M Muto
- Department of Veterinary Surgery, Azabu University, Kanagawa, Japan
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24
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Takekura H, Fujinami N, Nishizawa T, Ogasawara H, Kasuga N. Eccentric exercise-induced morphological changes in the membrane systems involved in excitation-contraction coupling in rat skeletal muscle. J Physiol 2001; 533:571-83. [PMID: 11389213 PMCID: PMC2278631 DOI: 10.1111/j.1469-7793.2001.0571a.x] [Citation(s) in RCA: 141] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. Physiological evidence suggests that excitation-contraction (E-C) coupling failure results from eccentric contraction-induced muscle injury because of structural and morphological damage to membrane systems directly associated with the E-C coupling processes within skeletal muscle fibres. In this study using rats, we observed the ultrastructural features of the membrane systems of fast-twitch (FT) and slow-twitch (ST) muscle fibres involved in E-C coupling following level and downhill running exercise. Our aim was to find out whether mechanically mediated events following eccentric exercise caused disorder in the membrane systems involved in E-C coupling, and how soon after exercise such disorder occurred. We also compared the morphological changes of the membrane systems between ST and FT muscle fibres within the same muscles. 2. Single muscle fibres were dissected from triceps brachii muscles of male Fischer 344 rats after level or downhill (16 deg decline) motor-driven treadmill running (18 m min(-1), 5 min running with 2 min rest interval, 18 bouts). All single muscle fibres were histochemically classified into ST or FT fibres. The membrane systems were visualized using Ca(2+)-K(3)Fe(CN)(6)-OsO(4) techniques, and observed by high voltage electron microscopy (120-200 kV). 3. There were four obvious ultrastructural changes in the arrangement of the transverse (t)-tubules and the disposition of triads after the downhill running exercise: (1) an increase in the number of longitudinal segments of the t-tubule network, (2) changes in the direction and disposition of triads, (3) the appearance of caveolar clusters, and (4) the appearance of pentads and heptads (close apposition of two or three t-tubule elements with three or four elements of terminal cisternae of the sarcoplasmic reticulum). The caveolar clusters appeared almost exclusively in the ST fibres immediately after downhill running exercise and again 16 h later. The pentads and heptads appeared almost exclusively in the FT fibres, and their numbers increased dramatically 2-3 days after the downhill running exercise. 4. The eccentric exercise led to the formation of abnormal membrane systems involved in E-C coupling processes. These systems have unique morphological features, which differ between ST and FT fibres, even within the same skeletal muscle, and the damage appears to be concentrated in the FT fibres. These observations also support the idea that eccentric exercise- induced E-C coupling failure is due to physical and chemical disruption of the membrane systems involved in the E-C coupling process in skeletal muscle.
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Affiliation(s)
- H Takekura
- Department of Physiological Sciences, National Institute of Fitness and Sports, Kanoya, Kagoshima 891-2393, Japan.
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25
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Bastide B, Conti A, Sorrentino V, Mounier Y. Properties of ryanodine receptor in rat muscles submitted to unloaded conditions. Biochem Biophys Res Commun 2000; 270:442-7. [PMID: 10753644 DOI: 10.1006/bbrc.2000.2446] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Unloading of skeletal muscles by hindlimb unweighting is known to induce muscle atrophy and a shift toward faster contractile properties associated with an increase in the expression of fast contractile proteins, particularly in slow soleus muscles. Contractile properties suggest that slow soleus muscles acquire SR properties close to those of a faster one. We studied the expression and properties of the sarcoplasmic reticulum calcium release (RyR) channels in soleus and gastrocnemius muscles of rats submitted to hindlimb unloading (HU). An increase in RyR1 and a slight decrease in RyR3 expression was detected in atrophied soleus muscles only after 4 weeks of HU. No variation appeared in fast muscles. [(3)H]Ryanodine binding experiments showed that HU neither increased the affinity of the receptors for [(3)H]ryanodine nor changed the caffeine sensitivity of [(3)H]ryanodine binding. Our results suggested that not only RyR1 but also RyR3 expression can be regulated by muscle activity and innervation in soleus muscle. The changes in the RyR expression in slow fibers suggested a transformation of the SR from a slow to a fast phenotype.
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Affiliation(s)
- B Bastide
- Laboratoire de plasticité neuromusculaire, USTL, Villeneuve d'Ascq Cedex, 59655, France.
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26
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Masini A, Scotti C, Calligaro A, Cazzalini O, Stivala LA, Bianchi L, Giovannini F, Ceccarelli D, Muscatello U, Tomasi A, Vannini V. Zidovudine-induced experimental myopathy: dual mechanism of mitochondrial damage. J Neurol Sci 1999; 166:131-40. [PMID: 10475107 DOI: 10.1016/s0022-510x(99)00126-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Myopathy often complicates Zidovudine (AZT) treatment in patients with acquired immunodeficiency syndrome (AIDS). The pathogenesis of the myopathy is controversial, since clinical phenomena intrinsic to AIDS may interfere per se with the onset of the myopathy. In the present work we investigated the in vivo effect of AZT in an animal model species (rat) not susceptible to HIV infection. Histochemical and electron microscopic analyses demonstrated that, under the experimental conditions used, the in vivo treatment with AZT does not cause in skeletal muscle true dystrophic lesions, but rather mitochondrial alterations confined to the fast fibers. In the same animal models, the biochemical analysis confirmed that mitochondria are the target of AZT toxicity in muscles. The effects of AZT on mitochondria energy transducing mechanisms were investigated in isolated mitochondria both in vivo and in vitro. Membrane potential abnormalities, due to a partial impairment of the respiratory chain capability observed in muscle mitochondria from AZT-treated rats, closely resemble those of control mitochondria in the presence of externally added AZT. mtDNA deletion analysis by PCR amplification and Southern blot analysis did not show any relevant deletion, while mtDNA depletion analysis demonstrated a significant decrease in mtDNA in AZT-treated rats. The present findings show that AZT causes damage to mitochondria by two mechanisms: a short-term mechanism that affects directly the respiratory chain, and a long-term mechanism that alters the mitochondrial DNA thus impairing the mitochondrial protein synthesis. In addition, the ultrastructural observations indicate that the fiber types are differently affected upon AZT treatment, which poses a number of questions as to the pathogenesis of this myopathy.
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Affiliation(s)
- A Masini
- Dipartimento di Scienze Biomediche, Università di Modena, Italy
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Takekura H, Kasuga N. Differential response of the membrane systems involved in excitation-contraction coupling to early and later postnatal denervation in rat skeletal muscle. J Muscle Res Cell Motil 1999; 20:279-89. [PMID: 10471991 DOI: 10.1023/a:1005447317302] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We compared the morphological features of the membrane systems involved in excitation-contraction (E-C) coupling during early postnatal development stages in rat skeletal muscles (tibialis anterior) denervated either at birth or 7 days after birth. Four obvious structural changes are observed in the arrangement of the transverse (T) tubule network and the disposition of triads following early postnatal denervation: (1) an increase in the longitudinal segments of the T tubule network, (2) changes in the direction and disposition of triads, (3) the appearance of caveolae clusters, (4) the appearance of pentads and heptads (i.e. a close apposition of two or three T tubule elements with three or four elements of terminal cisternae of sarcoplasmic reticulum). The increased presence of longitudinal T tubules parallels the loss of cross striations, and this in turn is due to misalignment of the myofibrils. The clusters of caveolae appear almost exclusively in muscle fibres denervated at birth, and pentads and heptads are more frequently observed in muscles denervated at 7 days. The differential growth of muscle fibres in response to denervation leads to the formation of abnormal membrane systems involved in the E-C coupling with very unique morphological features, which differ from the case of denervation in adult muscle fibres.
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Affiliation(s)
- H Takekura
- Department of Physiological Sciences, National Institute of Fitness and Sports, Kagoshima, Japan.
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