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Messa GAM, Korhonen MT, Degens H. No ageing-related increase in fibre type grouping in sprint-trained masters runners: A 10-year follow-up study. J Cachexia Sarcopenia Muscle 2024; 15:552-561. [PMID: 38228574 PMCID: PMC10995270 DOI: 10.1002/jcsm.13416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/09/2023] [Accepted: 11/28/2023] [Indexed: 01/18/2024] Open
Abstract
BACKGROUND Previous research suggests that an ageing-associated remodelling and loss of motor units due to motor neuron death contributes significantly to muscle weakness in old age. In histological sections, motor unit remodelling is reflected by increased fibre type grouping. While regular exercise may not attenuate the loss of motor units during ageing, it has been suggested to facilitate reinnervation resulting in larger motor units, and a higher number and larger fibre type groups in histological sections of muscles from aged individuals. METHODS In a 10-year follow-up study, we assessed changes in the prevalence and size of fibre type groups in the vastus lateralis muscle from 34 male masters sprinters (40-85 years at start). RESULTS Over the 10 years, there was an ageing-related reduction in performance in the 60-m sprint (P < 0.001) without significant changes in fibre type composition and fibre cross-sectional area. Neither the number of fibre type groups, defined as a fibre surrounded exclusively by fibres of the same type, nor the group size changed significantly in the 10-year period. CONCLUSIONS These histological data show that there is limited to no significant fibre type grouping over a 10-year period in masters athletes who continued sprint run training. This observation challenges the paradigm that ageing, at least in systematically trained sprinters, is associated with motor unit remodelling.
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Affiliation(s)
- Guy Anselme Mpaka Messa
- Higher Institute of Medical TechnologyISTM‐KinshasaKinshasaDemocratic Republic of Congo
- Faculty of MedicineUniversity Kasa‐Vubu (UKV)BomaDemocratic Republic of Congo
- Faculty of MedicineUniversity de Bandundu (UNIBAND)BandunduDemocratic Republic of Congo
| | - Marko T. Korhonen
- Gerontology Research Center, Faculty of Sport and Health SciencesUniversity of JyväskyläJyväskyläFinland
| | - Hans Degens
- Department of Life Sciences, Institute of SportManchester Metropolitan UniversityManchesterUK
- Institute of Sport Science and InnovationsLithuanian Sports UniversityKaunasLithuania
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2
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Fogarty MJ. Loss of larger hypoglossal motor neurons in aged Fischer 344 rats. Respir Physiol Neurobiol 2023:104092. [PMID: 37331418 DOI: 10.1016/j.resp.2023.104092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023]
Abstract
The intrinsic (longitudinal, transversalis and verticalis) and extrinsic (genioglossus, styloglossus, hyoglossus and geniohyoid) tongue muscles are innervated by hypoglossal motor neurons (MNs). Tongue muscle activations occur during many behaviors: maintaining upper airway patency, chewing, swallowing, vocalization, vomiting, coughing, sneezing and grooming/sexual activities. In the tongues of the elderly, reduced oral motor function and strength contribute to increased risk of obstructive sleep apnoea. Tongue muscle atrophy and weakness is also described in rats, yet hypoglossal MN numbers are unknown. In young (6-months, n=10) and old (24-months, n=8) female and male Fischer 344 (F344) rats, stereological assessment of hypoglossal MN numbers and surface areas were performed on 16µm Nissl-stained brainstem cryosections. We observed a robust loss of ~15% of hypoglossal MNs and a modest ~8% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of hypoglossal MNs approached ~30% These findings uncover a potential neurogenic locus of pathology for age-associated tongue dysfunctions.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905.
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Gras S, Blasco A, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Rueda R, Pereira SL, Navarro X, Esquerda JE, Calderó J. Beneficial effects of dietary supplementation with green tea catechins and cocoa flavanols on aging-related regressive changes in the mouse neuromuscular system. Aging (Albany NY) 2021; 13:18051-18093. [PMID: 34319911 PMCID: PMC8351677 DOI: 10.18632/aging.203336] [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: 04/29/2021] [Accepted: 06/19/2021] [Indexed: 12/17/2022]
Abstract
Besides skeletal muscle wasting, sarcopenia entails morphological and molecular changes in distinct components of the neuromuscular system, including spinal cord motoneurons (MNs) and neuromuscular junctions (NMJs); moreover, noticeable microgliosis has also been observed around aged MNs. Here we examined the impact of two flavonoid-enriched diets containing either green tea extract (GTE) catechins or cocoa flavanols on age-associated regressive changes in the neuromuscular system of C57BL/6J mice. Compared to control mice, GTE- and cocoa-supplementation significantly improved the survival rate of mice, reduced the proportion of fibers with lipofuscin aggregates and central nuclei, and increased the density of satellite cells in skeletal muscles. Additionally, both supplements significantly augmented the number of innervated NMJs and their degree of maturity compared to controls. GTE, but not cocoa, prominently increased the density of VAChT and VGluT2 afferent synapses on MNs, which were lost in control aged spinal cords; conversely, cocoa, but not GTE, significantly augmented the proportion of VGluT1 afferent synapses on aged MNs. Moreover, GTE, but not cocoa, reduced aging-associated microgliosis and increased the proportion of neuroprotective microglial phenotypes. Our data indicate that certain plant flavonoids may be beneficial in the nutritional management of age-related deterioration of the neuromuscular system.
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Affiliation(s)
- Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alejandro Barranco
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - Tapas Das
- Abbott Nutrition, Research and Development, Columbus, OH 43215, USA
| | - Ricardo Rueda
- Abbott Nutrition, Research and Development, Granada, Spain
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Josep E. Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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4
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Blasco A, Gras S, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Pereira SL, Navarro X, Rueda R, Esquerda JE, Calderó J. Motoneuron deafferentation and gliosis occur in association with neuromuscular regressive changes during ageing in mice. J Cachexia Sarcopenia Muscle 2020; 11:1628-1660. [PMID: 32691534 PMCID: PMC7749545 DOI: 10.1002/jcsm.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying the age-associated loss of muscle mass and function (sarcopenia) are poorly understood, hampering the development of effective treatment strategies. Here, we performed a detailed characterization of age-related pathophysiological changes in the mouse neuromuscular system. METHODS Young, adult, middle-aged, and old (1, 4, 14, and 24-30 months old, respectively) C57BL/6J mice were used. Motor behavioural and electrophysiological tests and histological and immunocytochemical procedures were carried out to simultaneously analyse structural, molecular, and functional age-related changes in distinct cellular components of the neuromuscular system. RESULTS Ageing was not accompanied by a significant loss of spinal motoneurons (MNs), although a proportion (~15%) of them in old mice exhibited an abnormally dark appearance. Dark MNs were also observed in adult (~9%) and young (~4%) animals, suggesting that during ageing, some MNs undergo early deleterious changes, which may not lead to MN death. Old MNs were depleted of cholinergic and glutamatergic inputs (~40% and ~45%, respectively, P < 0.01), suggestive of age-associated alterations in MN excitability. Prominent microgliosis and astrogliosis [~93% (P < 0.001) and ~100% (P < 0.0001) increase vs. adults, respectively] were found in old spinal cords, with increased density of pro-inflammatory M1 microglia and A1 astroglia (25-fold and 4-fold increase, respectively, P < 0.0001). Ageing resulted in significant reductions in the nerve conduction velocity and the compound muscle action potential amplitude (~30%, P < 0.05, vs. adults) in old distal plantar muscles. Compared with adult muscles, old muscles exhibited significantly higher numbers of both denervated and polyinnervated neuromuscular junctions, changes in fibre type composition, higher proportion of fibres showing central nuclei and lipofuscin aggregates, depletion of satellite cells, and augmented expression of different molecules related to development, plasticity, and maintenance of neuromuscular junctions, including calcitonin gene-related peptide, growth associated protein 43, agrin, fibroblast growth factor binding protein 1, and transforming growth factor-β1. Overall, these alterations occurred at varying degrees in all the muscles analysed, with no correlation between the age-related changes observed and myofiber type composition or muscle topography. CONCLUSIONS Our data provide a global view of age-associated neuromuscular changes in a mouse model of ageing and help to advance understanding of contributing pathways leading to development of sarcopenia.
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Affiliation(s)
- Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | | | - Tapas Das
- Abbott Nutrition Research and Development, Columbus, OH, USA
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Ricardo Rueda
- Abbott Nutrition Research and Development, Granada, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
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Larsson L, Degens H, Li M, Salviati L, Lee YI, Thompson W, Kirkland JL, Sandri M. Sarcopenia: Aging-Related Loss of Muscle Mass and Function. Physiol Rev 2019; 99:427-511. [PMID: 30427277 DOI: 10.1152/physrev.00061.2017] [Citation(s) in RCA: 718] [Impact Index Per Article: 143.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility, diminishes quality of life, and can lead to fall-related injuries, which require costly hospitalization and extended rehabilitation. This review focuses on the aging-related structural changes and mechanisms at cellular and subcellular levels underlying changes in the individual motor unit: specifically, the perikaryon of the α-motoneuron, its neuromuscular junction(s), and the muscle fibers that it innervates. Loss of muscle mass with aging, which is largely due to the progressive loss of motoneurons, is associated with reduced muscle fiber number and size. Muscle function progressively declines because motoneuron loss is not adequately compensated by reinnervation of muscle fibers by the remaining motoneurons. At the intracellular level, key factors are qualitative changes in posttranslational modifications of muscle proteins and the loss of coordinated control between contractile, mitochondrial, and sarcoplasmic reticulum protein expression. Quantitative and qualitative changes in skeletal muscle during the process of aging also have been implicated in the pathogenesis of acquired and hereditary neuromuscular disorders. In experimental models, specific intervention strategies have shown encouraging results on limiting deterioration of motor unit structure and function under conditions of impaired innervation. Translated to the clinic, if these or similar interventions, by saving muscle and improving mobility, could help alleviate sarcopenia in the elderly, there would be both great humanitarian benefits and large cost savings for health care systems.
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Affiliation(s)
- Lars Larsson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Hans Degens
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Meishan Li
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Leonardo Salviati
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Young Il Lee
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Wesley Thompson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - James L Kirkland
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Marco Sandri
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
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Wang W, Qi B, Lv H, Wu F, Liu L, Wang W, Wang Q, Hu L, Hao Y, Wang Y. A new method of isolating spinal motor neurons from fetal mouse. J Neurosci Methods 2017. [PMID: 28648716 DOI: 10.1016/j.jneumeth.2017.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Isolating of primary motor neurons from animal embryos is critical for the study of neurological disease including mechanistic discovery and therapeutic development. Density gradient centrifuge taking advantage of the buoyant of motor neuron permits the enrichment of motor neurons. Despite the metrizamide, an OptiPrep medium has been introduced to separate the motor neurons by gradient centrifuge. NEW METHOD We hereby used single density gradient of OptiPrep medium to isolate the spinal motor neurons from the fetal mouse. RESULTS Single density gradient of OptiPrep medium is effective to isolate spinal motor neurons from the fetal mouse. The immunofluorescence staining analysis showed that the purity of cultured motor neurons at 72h was between 90% and 95%. COMPARISON WITH EXISTING METHOD Four gradients of OptiPrep medium have been previously used to isolate the motor neurons from spinal cord of mouse. In this study, the single gradient of OptiPrep medium was demonstrated to effectively isolate spinal motor neurons from the fetal mouse. CONCLUSIONS The single gradient of OptiPrep medium is enough to produce high purity of spinal motor neurons from the fetal mouse.
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Affiliation(s)
- Weifang Wang
- Graduate School of Shandong University, Jinan, Shandong Province, People's Republic of China; Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Bao Qi
- Graduate School of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Hui Lv
- Graduate School of Tianjin Medical University, Tianjin, People's Republic of China
| | - Fei Wu
- Department of Neurobiology, Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Lulu Liu
- Central Laboratory, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Wei Wang
- Department of Pathology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Quanquan Wang
- Graduate School of Shandong University, Jinan, Shandong Province, People's Republic of China; Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Liangchen Hu
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China; Graduate School of Jining Medical University, Jining, Shandong Province, People's Republic of China
| | - Yanlei Hao
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China.
| | - Yuzhong Wang
- Department of Neurology, Affiliated Hospital of Jining Medical University, Jining, Shandong Province, People's Republic of China.
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Marcon RM, Cristante AF, de Barros Filho TEP, Ferreira R, dos Santos GB. Effects of ganglioside G(M1) and erythropoietin on spinal cord lesions in rats: functional and histological evaluations. Clinics (Sao Paulo) 2016; 71:351-60. [PMID: 27438570 PMCID: PMC4930661 DOI: 10.6061/clinics/2016(06)11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/21/2016] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE To evaluate the functional and histological effects of ganglioside G(M1) and erythropoietin after experimental spinal cord contusion injury. METHODS Fifty male Wistar rats underwent experimental spinal cord lesioning using an NYU-Impactor device and were randomly divided into the following groups, which received treatment intraperitoneally. The G(M1) group received ganglioside G(M1) (30 mg/kg); the erythropoietin group received erythropoietin (1000 IU/kg); the combined group received both drugs; and the saline group received saline (0.9%) as a control. A fifth group was the laminectomy group, in which the animals were subjected to laminectomy alone, without spinal lesioning or treatment. The animals were evaluated according to the Basso, Beattie and Bresnahan (BBB) scale, motor evoked potential recordings and, after euthanasia, histological analysis of spinal cord tissue. RESULTS The erythropoietin group had higher BBB scores than the G(M1) group. The combined group had the highest BBB scores, and the saline group had the lowest BBB scores. No significant difference in latency was observed between the three groups that underwent spinal cord lesioning and intervention. However, the combined group showed a significantly higher signal amplitude than the other treatment groups or the saline group (p<0.01). Histological tissue analysis showed no significant difference between the groups. Axonal index was significantly enhanced in the combined group than any other intervention (p<0.01). CONCLUSION G(M1) and erythropoietin exert therapeutic effects on axonal regeneration and electrophysiological and motor functions in rats subjected to experimental spinal cord lesioning and administering these two substances in combination potentiates their effects.
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Affiliation(s)
- Raphael Martus Marcon
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (IOT-HCFMUSP), Divisão de Cirurgia de Coluna Vertebral, Laboratório de Investigação Médica (LIM 41), São Paulo/SP, Brazil
- E-mail: .
| | - Alexandre Fogaça Cristante
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (IOT-HCFMUSP), Divisão de Cirurgia de Coluna Vertebral, Laboratório de Investigação Médica (LIM 41), São Paulo/SP, Brazil
| | - Tarcísio Eloy Pessoa de Barros Filho
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (IOT-HCFMUSP), Divisão de Cirurgia de Coluna Vertebral, Laboratório de Investigação Médica (LIM 41), São Paulo/SP, Brazil
| | - Ricardo Ferreira
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (IOT-HCFMUSP), Divisão de Cirurgia de Coluna Vertebral, Laboratório de Investigação Médica (LIM 41), São Paulo/SP, Brazil
| | - Gustavo Bispo dos Santos
- Instituto de Ortopedia e Traumatologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (IOT-HCFMUSP), Divisão de Cirurgia de Coluna Vertebral, Laboratório de Investigação Médica (LIM 41), São Paulo/SP, Brazil
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8
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Perturbed cholesterol homeostasis in aging spinal cord. Neurobiol Aging 2016; 45:123-135. [PMID: 27459933 DOI: 10.1016/j.neurobiolaging.2016.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 04/28/2016] [Accepted: 05/16/2016] [Indexed: 12/14/2022]
Abstract
The spinal cord is vital for the processing of sensorimotor information and for its propagation to and from both the brain and the periphery. Spinal cord function is affected by aging, however, the mechanisms involved are not well-understood. To characterize molecular mechanisms of spinal cord aging, microarray analyses of gene expression were performed on cervical spinal cords of aging rats. Of the metabolic and signaling pathways affected, cholesterol-associated pathways were the most comprehensively altered, including significant downregulation of cholesterol synthesis-related genes and upregulation of cholesterol transport and metabolism genes. Paradoxically, a significant increase in total cholesterol content was observed-likely associated with cholesterol ester accumulation. To investigate potential mechanisms for the perturbed cholesterol homeostasis, we quantified the expression of myelin and neuroinflammation-associated genes and proteins. Although there was minimal change in myelin-related expression, there was an increase in phagocytic microglial and astrogliosis markers, particularly in the white matter. Together, these results suggest that perturbed cholesterol homeostasis, possibly as a result of increased inflammatory activation in spinal cord white matter, may contribute to impaired spinal cord function with aging.
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Lavinsky D, Wang J, Huie P, Dalal R, Lee SJ, Lee DY, Palanker D. Nondamaging Retinal Laser Therapy: Rationale and Applications to the Macula. Invest Ophthalmol Vis Sci 2016; 57:2488-500. [PMID: 27159441 PMCID: PMC5995023 DOI: 10.1167/iovs.15-18981] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/25/2016] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Retinal photocoagulation and nondamaging laser therapy are used for treatment of macular disorders, without understanding of the response mechanism and with no rationale for dosimetry. To establish a proper titration algorithm, we measured the range of tissue response and damage threshold. We then evaluated safety and efficacy of nondamaging retinal therapy (NRT) based on this algorithm for chronic central serous chorioretinopathy (CSCR) and macular telangiectasia (MacTel). METHODS Retinal response to laser treatment below damage threshold was assessed in pigmented rabbits by expression of the heat shock protein HSP70 and glial fibrillary acidic protein (GFAP). Energy was adjusted relative to visible titration using the Endpoint Management (EpM) algorithm. In clinical studies, 21 eyes with CSCR and 10 eyes with MacTel were treated at 30% EpM energy with high spot density (0.25-diameter spacing). Visual acuity, retinal and choroidal thickness, and subretinal fluid were monitored for 1 year. RESULTS At 25% EpM energy and higher, HSP70 was expressed acutely in RPE, and GFAP upregulation in Müller cells was observed at 1 month. Damage appeared starting at 40% setting. Subretinal fluid resolved completely in 81% and partially in 19% of the CSCR patients, and visual acuity improved by 12 ± 3 letters. Lacunae in the majority of MacTel patients decreased while preserving the retinal thickness, and vision improved by 10 letters. CONCLUSIONS Heat shock protein expression in response to hyperthermia helps define the therapeutic window for NRT. Lack of tissue damage enables high-density treatment to boost clinical efficacy, therapy in the fovea, and retreatments to manage chronic diseases.
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Affiliation(s)
- Daniel Lavinsky
- Department of Ophthalmology, Federal University Rio Grande do Sul, Porto Alegre, Brazil
| | - Jenny Wang
- Department of Applied Physics, Stanford University, Stanford, California, United States
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
| | - Philip Huie
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Roopa Dalal
- Department of Ophthalmology, Stanford University, Stanford, California, United States
| | - Seung Jun Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Kangwon National University, Chuncheon, South Korea
| | - Dae Yeong Lee
- Department of Ophthalmology, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, South Korea
| | - Daniel Palanker
- Hansen Experimental Physics Laboratory, Stanford University, Stanford, California, United States
- Department of Ophthalmology, Stanford University, Stanford, California, United States
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Ballak SB, Degens H, de Haan A, Jaspers RT. Aging related changes in determinants of muscle force generating capacity: a comparison of muscle aging in men and male rodents. Ageing Res Rev 2014; 14:43-55. [PMID: 24495393 DOI: 10.1016/j.arr.2014.01.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 01/20/2014] [Accepted: 01/24/2014] [Indexed: 12/25/2022]
Abstract
Human aging is associated with a progressive decline in skeletal muscle mass and force generating capacity, however the exact mechanisms underlying these changes are not fully understood. Rodents models have often been used to enhance our understanding of mechanisms of age-related changes in human skeletal muscle. However, to what extent age-related alterations in determinants of muscle force generating capacity observed in rodents resemble those in humans has not been considered thoroughly. This review compares the effect of aging on muscle force generating determinants (muscle mass, fiber size, fiber number, fiber type distribution and muscle specific tension), in men and male rodents at similar relative age. It appears that muscle aging in male F344*BN rat resembles that in men most; 32-35-month-old rats exhibit similar signs of muscle weakness to those of 70-80-yr-old men, and the decline in 36-38-month-old rats is similar to that in men aged over 80 yrs. For male C57BL/6 mice, age-related decline in muscle force generating capacity seems to occur only at higher relative age than in men. We conclude that the effects on determinants of muscle force differ between species as well as within species, but qualitatively show the same pattern as that observed in men.
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Affiliation(s)
- Sam B Ballak
- School of Healthcare Science, Cognitive Motor Function Research Group, Manchester Metropolitan University, Manchester M1 5GD, United Kingdom; Laboratory for Myology, Move Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam 1081 BT, The Netherlands.
| | - Hans Degens
- School of Healthcare Science, Cognitive Motor Function Research Group, Manchester Metropolitan University, Manchester M1 5GD, United Kingdom
| | - Arnold de Haan
- School of Healthcare Science, Cognitive Motor Function Research Group, Manchester Metropolitan University, Manchester M1 5GD, United Kingdom; Laboratory for Myology, Move Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam 1081 BT, The Netherlands
| | - Richard T Jaspers
- Laboratory for Myology, Move Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam 1081 BT, The Netherlands
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Power GA, Dalton BH, Rice CL. Human neuromuscular structure and function in old age: A brief review. JOURNAL OF SPORT AND HEALTH SCIENCE 2013; 2:215-226. [PMID: 27011872 PMCID: PMC4801513 DOI: 10.1016/j.jshs.2013.07.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Natural adult aging is associated with many functional impairments of the human neuromuscular system. One of the more observable alterations is the loss of contractile muscle mass, termed sarcopenia. The loss of muscle mass occurs primarily due to a progressive loss of viable motor units, and accompanying atrophy of remaining muscle fibers. Not only does the loss of muscle mass contribute to impaired function in old age, but alterations in fiber type and myosin heavy chain isoform expression also contribute to weaker, slower, and less powerful contracting muscles. This review will focus on motor unit loss associated with natural adult aging, age-related fatigability, and the age-related differences in strength across contractile muscle actions.
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Affiliation(s)
- Geoffrey A. Power
- Human Performance Laboratory, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Brian H. Dalton
- School of Kinesiology, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Charles L. Rice
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario N6A 5B1, Canada
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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Abstract
Heat shock proteins (HSP) are molecular chaperones and have been implicated in longevity and aging in many species. Their major functions include chaperoning misfolded or newly synthesised polypeptides, protecting cells from proteotoxic stress, and processing of immunogenic agents. These proteins are expressed constitutively and can be induced by stresses such as heat, oxidative stress and many more. The induction of HSP in aging could potentially maintain protein homeostasis and longevity by refolding the damaged proteins which accumulate during aging and are toxic to cells. HSP are shown to increase life span in model organisms such as Caenorhabditis elegans and decrease aging-related proteotoxicity. Thus, decrease in HSP in aging is associated with disruption of cellular homeostasis which causes diseases such as cancer, cell senescence and neurodegeneration. HSP levels are decreased with aging in most organs including neurons. Aging also causes attenuation or alteration of many signalling pathways as well as the expression of transcription factors such as heat shock factor (HSF). The alteration in regulation and synthesis of Forkhead box O3a (FoxO3a) family of transcription factors as well as major antioxidant enzymes (manganese superoxide dismutase, catalase) are also seen in aging. Among many signalling mechanisms involved in altering longevity and aging, the insulin/IGF-1 pathway and the Sir2 deacetylase are highly significant. This review enquires into the role of some of these pathways in longevity/aging along with HSP.
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Affiliation(s)
- Ayesha Murshid
- Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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Cristante AF, Filho TEPB, Oliveira RP, Marcon RM, Ferreira R, Santos GB. Effects of antidepressant and treadmill gait training on recovery from spinal cord injury in rats. Spinal Cord 2013; 51:501-7. [PMID: 23567756 DOI: 10.1038/sc.2013.18] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
STUDY DESIGN Experimental, controlled, animal study. OBJECTIVES To evaluate the influences of antidepressant treatment, treadmill gait training and a combination of these therapies in rats with experimental, acute spinal cord injury (SCI). SETTING Brazil. METHODS 48 Wistar rats were given standardized SCI; rats were then randomly assigned to four treatment groups: (1) motor rehabilitation therapy for 1 hour daily (gait training); (2) daily treatment with the antidepressant, fluoxetine (0.3 ml per 100 g intraperitoneally), beginning 24 h after the trauma; (3) combined fluoxetine treatment and gait training, or (4) untreated (controls). Neurological recovery was tested with the Basso, Beattie and Bresnahan (BBB) scale at 2, 7, 14, 21, 28 ,35 and 42 days after injury. Moreover, on day 42, all rats underwent a motor-evoked potential test (MEP); then, after euthanasia, histopathological evaluation was conducted in the area of SCI. RESULTS Based on the BBB scale, the combined treatment group showed significantly greater improvement compared with the other three groups, from the 14th to the 42nd day of observation. The MEP revealed that all treated groups showed significant improvement compared with the control group (P<0.02 for latency and P<0.01 for amplitude). CONCLUSION Our results indicated that a combination of antidepressant and treadmill gait training was superior to either treatment alone for improving functional deficits in rats with experimental, acute SCI.
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Affiliation(s)
- A F Cristante
- Department of Orthopaedics and Traumatology, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Pauloo, São Paulo, Brazil.
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Power GA, Dalton BH, Behm DG, Doherty TJ, Vandervoort AA, Rice CL. Motor unit survival in lifelong runners is muscle dependent. Med Sci Sports Exerc 2012; 44:1235-42. [PMID: 22246219 DOI: 10.1249/mss.0b013e318249953c] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED A contributing factor to the loss of muscle mass and strength with adult aging is the reduction in the number of functioning motor units (MUs). Recently, we reported that lifelong competitive runners (master runners = ~66 yr) had greater numbers of MUs in a leg muscle (tibialis anterior) than age-matched recreationally active controls. This suggested that long-term exposure to high levels of physical activity may limit the loss of MU numbers with adult aging. However, it is unknown if this finding is the result of long-term activation of the specifically exercised motoneuron pool (i.e., tibialis anterior) or an overall systemic neuroprotective effect of high levels of physical activity. PURPOSE The purpose was to estimate the number of functioning MUs (MUNEs) in the biceps brachii (an upper body muscle not directly loaded by running) of nine young (27 ± 5 yr) and nine old (70 ± 5 yr) men and nine lifelong competitive master runners (67 ± 4 yr). METHODS Decomposition-enhanced spike-triggered averaging was used to measure surface and intramuscular EMG signals during elbow flexion at 10% of maximum voluntary isometric contraction. RESULTS Derived MUNEs were lower in the biceps brachii of runners (185 ± 69 MUs) and old men (133 ± 69 MUs) than the young (354 ± 113 MUs), but the old and master runners were similar. CONCLUSIONS Although there were no significant differences in MUNE between both older groups in the biceps brachii muscle, with the number of subjects tested here, we cannot eliminate the possibility of some whole-body neuroprotective effect. However, when compared with the remote biceps muscle, a greater influence on age-related spinal motoneuron survival was found in a chronically activated MN pool specific to the exercised muscle.
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Affiliation(s)
- Geoffrey A Power
- Canadian Centre for Activity and Aging, School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London, Ontario, Canada
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Loncarevic-Vasiljkovic N, Pesic V, Todorovic S, Popic J, Smiljanic K, Milanovic D, Ruzdijic S, Kanazir S. Caloric restriction suppresses microglial activation and prevents neuroapoptosis following cortical injury in rats. PLoS One 2012; 7:e37215. [PMID: 22615943 PMCID: PMC3352891 DOI: 10.1371/journal.pone.0037215] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 04/17/2012] [Indexed: 12/21/2022] Open
Abstract
Traumatic brain injury (TBI) is a widespread cause of death and a major source of adult disability. Subsequent pathological events occurring in the brain after TBI, referred to as secondary injury, continue to damage surrounding tissue resulting in substantial neuronal loss. One of the hallmarks of the secondary injury process is microglial activation resulting in increased cytokine production. Notwithstanding that recent studies demonstrated that caloric restriction (CR) lasting several months prior to an acute TBI exhibits neuroprotective properties, understanding how exactly CR influences secondary injury is still unclear. The goal of the present study was to examine whether CR (50% of daily food intake for 3 months) alleviates the effects of secondary injury on neuronal loss following cortical stab injury (CSI). To this end, we examined the effects of CR on the microglial activation, tumor necrosis factor-α (TNF-α) and caspase-3 expression in the ipsilateral (injured) cortex of the adult rats during the recovery period (from 2 to 28 days) after injury. Our results demonstrate that CR prior to CSI suppresses microglial activation, induction of TNF-α and caspase-3, as well as neurodegeneration following injury. These results indicate that CR strongly attenuates the effects of secondary injury, thus suggesting that CR may increase the successful outcome following TBI.
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Affiliation(s)
| | - Vesna Pesic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Smilja Todorovic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Jelena Popic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Kosara Smiljanic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Desanka Milanovic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Sabera Ruzdijic
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
| | - Selma Kanazir
- Department of Neurobiology, Institute for Biological Research, University of Belgrade, Belgrade, Republic of Serbia
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Denervation causes fiber atrophy and myosin heavy chain co-expression in senescent skeletal muscle. PLoS One 2012; 7:e29082. [PMID: 22235261 PMCID: PMC3250397 DOI: 10.1371/journal.pone.0029082] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 11/21/2011] [Indexed: 01/06/2023] Open
Abstract
Although denervation has long been implicated in aging muscle, the degree to which it is causes the fiber atrophy seen in aging muscle is unknown. To address this question, we quantified motoneuron soma counts in the lumbar spinal cord using choline acetyl transferase immunhistochemistry and quantified the size of denervated versus innervated muscle fibers in the gastrocnemius muscle using the in situ expression of the denervation-specific sodium channel, Nav1.5, in young adult (YA) and senescent (SEN) rats. To gain insights into the mechanisms driving myofiber atrophy, we also examined the myofiber expression of the two primary ubiquitin ligases necessary for muscle atrophy (MAFbx, MuRF1). MN soma number in lumbar spinal cord declined 27% between YA (638±34 MNs×mm−1) and SEN (469±13 MNs×mm−1). Nav1.5 positive fibers (1548±70 μm2) were 35% smaller than Nav1.5 negative fibers (2367±78 μm2; P<0.05) in SEN muscle, whereas Nav1.5 negative fibers in SEN were only 7% smaller than fibers in YA (2553±33 μm2; P<0.05) where no Nav1.5 labeling was seen, suggesting denervation is the primary cause of aging myofiber atrophy. Nav1.5 positive fibers had higher levels of MAFbx and MuRF1 (P<0.05), consistent with involvement of the proteasome proteolytic pathway in the atrophy of denervated muscle fibers in aging muscle. In summary, our study provides the first quantitative assessment of the contribution of denervation to myofiber atrophy in aging muscle, suggesting it explains the majority of the atrophy we observed. This striking result suggests a renewed focus should be placed on denervation in seeking understanding of the causes of and treatments for aging muscle atrophy.
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Hwang IK, Ahn JH, Yoo DY, Lee CH, Yoo KY, Choi JH, Moon SM, Shin HC, Won MH. Increased immunoreactivities of cleaved αII-spectrin and cleaved caspase-3 in the aged dog spinal cord. Neurochem Res 2011; 37:480-6. [PMID: 22037840 DOI: 10.1007/s11064-011-0633-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 09/05/2011] [Accepted: 10/13/2011] [Indexed: 11/27/2022]
Abstract
The activation of caspase-3 is considered to be a reliable marker for apoptotic cell death, and a 120-kDa fragment of αII-spectrin is generated by caspase-3 mediated cleavage of this structural protein. In the present study, we compared cleaved αII-spectrin (120-kDa) and cleaved caspase-3-immunoreactive cells and their protein levels in the cervical (C₅-C₆) and lumbar (L₃-L₄) levels of the spinal cord in adult (1-2 year-old) and aged (10-12 year-old) dogs (German shepherds). Weak cleaved αII-spectrin and cleaved caspase-3 immunoreactivity was found in neurons of the adult group; however, their immunoreactivity was distinctively increased in the neuronal cytoplasm in the aged group compared to those in the adult group, although the distribution pattern of their neurons was similar between the adult and age group. In addition, cleaved αII-spectrin and cleaved caspase-3 levels in the aged spinal cord were markedly increased compared to those in the adult group. These findings suggest that the increases of cleaved αII-spectrin and cleaved caspase-3 immunoreactivity may be related to aging of the spinal cord in dogs.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, South Korea
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