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1.
J Orthop Res ; 41(12): 2579-2587, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37132369

RESUMO

Whole-body vibration has been considered as a countermeasure against muscle atrophy. However, its effects on muscle atrophy are poorly understood. We evaluated the effects of whole-body vibration on denervated skeletal muscle atrophy. Whole-body vibration was performed on rats from Day 15 to 28 after denervation injury. Motor performance was evaluated using an inclined-plane test. Compound muscle action potentials of the tibial nerve were examined. Muscle wet weight and muscle fiber cross-sectional area were measured. Myosin heavy chain isoforms were analyzed in both muscle homogenates and single myofibers. Whole-body vibration resulted in a significantly decreased inclination angle and muscle weight, but not muscle fiber cross-sectional area of fast-twitch gastrocnemius compared to denervation only. In denervated gastrocnemius, a fast-to-slow shift was observed in myosin heavy chain isoform composition following whole-body vibration. There were no significant changes in muscle weight, muscle fiber cross-sectional area, and myosin heavy chain isoform composition in denervated slow-twitch soleus. These results imply that whole-body vibration does not promote recovery of denervation-induced muscle atrophy.


Assuntos
Cadeias Pesadas de Miosina , Vibração , Ratos , Animais , Vibração/uso terapêutico , Denervação Muscular/métodos , Atrofia Muscular/etiologia , Atrofia Muscular/terapia , Músculo Esquelético/fisiologia , Isoformas de Proteínas , Fibras Musculares de Contração Lenta , Fibras Musculares de Contração Rápida
2.
Methods Mol Biol ; 2640: 217-225, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36995598

RESUMO

The nerve transection model is an established and validated experimental model of skeletal muscle atrophy prepared by denervating the skeletal muscle in rodents. While a number of denervation techniques are available in rats, the development of various transgenic and knockout mice has also led to the wide use of mouse models of nerve transection. Skeletal muscle denervation experiments expand our knowledge of the physiological role of nerval activity and/or neurotrophic factors in the plasticity of skeletal muscle. The denervation of the sciatic or tibial nerve is a common experimental procedure in mice and rats, as these nerves can be resected without great difficulty. An increasing number of reports have recently been published on experiments using a tibial nerve transection technique in mice. In this chapter, we demonstrate and explain the procedures used to transect the sciatic and tibial nerves in mice.


Assuntos
Denervação Muscular , Nervo Isquiático , Ratos , Camundongos , Animais , Denervação Muscular/métodos , Nervo Isquiático/fisiologia , Músculo Esquelético/patologia , Nervo Tibial/fisiologia , Atrofia Muscular/patologia
3.
J Reconstr Microsurg ; 39(9): 695-704, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36948213

RESUMO

BACKGROUND: We have developed a novel muscle reinnervation technique called "nerve-muscle-endplate grafting (NMEG) in the native motor zone (NMZ)." This study aimed to augment the outcomes of the NMEG-NMZ (NN) by focal application of exogenous neurotrophic factors (ENFs) for limb reinnervation. METHODS: Adult rats were used to conduct NN plus ENF (NN/ENF) and autologous nerve grafting (ANG, technique control). The nerve innervating the left tibialis anterior (TA) muscle was resected and the denervated TA was immediately treated with NN/ENF or ANG. For NN procedure, an NMEG pedicle was taken from the lateral gastrocnemius muscle and transferred to the NMZ of the denervated TA. For ANG, the nerve gap was bridged with sural nerve. Three months after treatment, the extent of functional and neuromuscular recovery was assessed by measuring static toe spread, maximal muscle force, wet muscle weight, regenerated axons, and innervated motor endplates (MEPs). RESULTS: NN/ENF resulted in 90% muscle force recovery of the treated TA, which is far superior to ANG (46%) and NN alone (79%) as reported elsewhere. Toe spread recovered up to 89 and 49% of the control for the NN/ENF and ANG groups, respectively. The average wet muscle weight was 87 and 52% of the control for muscles treated with NN/ENF and ANG, respectively. The mean number of the regenerated axons was 88% of the control for the muscles treated with NN/ENF, which was significantly larger than that for the ANG-repaired muscles (39%). The average percentage of the innervated MEPs in the NN/ENF-treated TA (89%) was higher compared with that in the ANG-repaired TA (48%). CONCLUSION: ENF enhances nerve regeneration and MEP reinnervation that further augment outcomes of NN. The NN technique could be an alternative option to treat denervated or paralyzed limb muscles caused by traumatic nerve injuries or lesions.


Assuntos
Fatores de Crescimento Neural , Procedimentos Neurocirúrgicos , Ratos , Animais , Procedimentos Neurocirúrgicos/métodos , Regeneração Nervosa/fisiologia , Músculo Esquelético/inervação , Placa Motora/patologia , Denervação Muscular/métodos
4.
Neurosurgery ; 92(5): 1091-1098, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-36700699

RESUMO

BACKGROUND: We have developed a novel reinnervation technique called nerve-muscle-endplate grafting in the native motor zone (NMEG-NMZ). However, it remains unknown whether the NMEG-NMZ is effective for limb reinnervation. OBJECTIVE: To evaluate the efficacy of the NMEG-NMZ in limb muscle reinnervation. METHODS: Forty-five adult rats were divided into 3 groups: NMEG, end-to-end anastomosis (EEA, technique control), and denervation control (DC). The left tibialis anterior muscle was denervated by resecting its nerve. For NMEG-NMZ, the denervated tibialis anterior was reinnervated by transferring a NMEG pedicle from the lateral gastrocnemius muscle. Three months after surgery, static toe spread analysis was performed for all rats and muscle force was measured for the rats treated with NMEG and EEA. Muscle weight, myofiber morphology, regenerated axons, and reinnervated motor endplates in the treated muscles were also quantified and compared with those in the DC group. RESULTS: NMEG-NMZ technique resulted in better muscle force recovery (79% of the control) compared with EEA (51% of the control, P = .048). Toe spread analysis in NMEG-NMZ reinnervated muscles showed static sciatic index = -16.8, whereas -41.4 in EEA, P < .0001). The average weight of the NMEG-NMZ reinnervated muscles (86%) was greater than those of the EEA treated (71%) and DC (26%) muscles (all P < .0001). The mean count of the regenerated axons in the muscles with NMEG-NMZ was 76% of the control, which was larger than that in the muscles with EEA (46%), P < .0001. CONCLUSION: NMEG-NMZ technique has unique advantages and is superior to EEA for muscle reinnervation and functional recovery.


Assuntos
Regeneração Nervosa , Neurogênese , Ratos , Animais , Regeneração Nervosa/fisiologia , Ratos Sprague-Dawley , Neurogênese/fisiologia , Procedimentos Neurocirúrgicos/métodos , Músculo Esquelético/inervação , Denervação Muscular/métodos
5.
Biochem Pharmacol ; 203: 115186, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35882305

RESUMO

The molecular mechanism underlying denervation-induced muscle atrophy is complex and incompletely understood. Our previous results suggested that inflammation may play an important role in the early stages of muscle atrophy. Celecoxib is reported to exert anti-inflammatory effects. Here, we explored the effect of celecoxib on denervation-induced muscle atrophy and sought to identify the mechanism involved. We found that celecoxib treatment significantly increased the wet weight ratio and CSA of the tibialisanteriormuscle. Additionally, celecoxib downregulated the levels of COX-2, inflammatory factors and reduced inflammatory cell infiltration. GO and KEGG pathway enrichment analysis indicated that after 3 days of celecoxib treatment in vivo, the differentially expressed genes (DEGs) were mainly associated with the regulation of immune responses related to complement activation; after 14 days, the DEGs were mainly involved in the regulation of oxidative stress and inflammation-related responses. Celecoxib administration reduced the levels of ROS and oxidative stress-related proteins. Furthermore, we found that celecoxib treatment inhibited the denervation-induced up-regulation of the ubiquitin-proteasome and autophagy-lysosomal systems related proteins; decreased mitophagy in target muscles; and increased levels of MHC. Finally, celecoxib also attenuated microvascular damage in denervated skeletal muscle. Combined, our findings demonstrated that celecoxib inhibits inflammation and oxidative stress in denervated skeletal muscle, thereby suppressing mitophagy and proteolysis, improving blood flow in target muscles, and, ultimately, alleviating denervation-induced muscle atrophy. Our results confirmed that inflammatory responses play a key role in denervation-induced muscle atrophy and highlight a novel strategy for the prevention and treatment of this condition.


Assuntos
Denervação Muscular , Atrofia Muscular , Celecoxib/farmacologia , Celecoxib/uso terapêutico , Humanos , Inflamação/metabolismo , Microcirculação , Denervação Muscular/métodos , Músculo Esquelético , Atrofia Muscular/tratamento farmacológico , Atrofia Muscular/metabolismo , Estresse Oxidativo
7.
Life Sci ; 287: 120117, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34740577

RESUMO

Denervated skeletal muscular atrophy is primarily characterized by loss of muscle strength and mass and an unideal functional recovery of the muscle after extended denervation. This review emphasizes the interaction between the immune system and the denervated skeletal muscle. Immune cells such as neutrophils, macrophages and T-cells are activated and migrate to denervated muscle, where they release a high concentration of cytokines and chemokines. The migration of these immune cells, the transformation of different functional immune cell subtypes, and the cytokine network in the immune microenvironment may be involved in the regulatory process of muscle atrophy or repair. However, the exact mechanisms of the interaction between these immune cells and immune molecules in skeletal muscles are unclear. In this paper, the immune microenvironment regulation of muscle atrophy induced by peripheral nerve injury is reviewed.


Assuntos
Pesquisa Biomédica/tendências , Microambiente Celular/fisiologia , Imunidade Celular/fisiologia , Músculo Esquelético/imunologia , Atrofia Muscular/imunologia , Traumatismos dos Nervos Periféricos/imunologia , Animais , Humanos , Macrófagos/imunologia , Macrófagos/metabolismo , Denervação Muscular/métodos , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo
8.
Life Sci ; 286: 120067, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34678261

RESUMO

AIMS: Brain derived neurotrophic factor (BDNF) and the related receptors TrkB and p75NTR are expressed in skeletal muscle, yet their functions remain to be fully understood. Skeletal muscle denervation, which occurs in spinal injury, peripheral neuropathies, and aging, negatively affects muscle mass and function. In this study, we wanted to understand the role of BDNF, TrkB, and p75NTR in denervation-induced adverse effects on skeletal muscle. MAIN METHODS: Mice with unilateral sciatic denervation were used. Protein levels of pro- and mature BDNF, TrkB, p75NTR, activations of their downstream signaling pathways, and inflammation in the control and denervated muscle were measured with Western blot and tissue staining. Treatment with a p75NTR inhibitor and BDNF skeletal muscle specific knockout in mice were used to examine the role of p75NTR and pro-BDNF. KEY FINDINGS: In denervated muscle, pro-BDNF and p75NTR were significantly upregulated, and JNK and NF-kB, two major downstream signaling pathways of p75NTR, were activated, along with muscle atrophy and inflammation. Inhibition of p75NTR using LM11A-31 significantly reduced JNK activation and inflammatory cytokines in the denervated muscle. Moreover, skeletal muscle specific knockout of BDNF reduced pro-BDNF level, JNK activation and inflammation in the denervated muscle. SIGNIFICANCE: These results reveal for the first time that the upregulation of pro-BDNF and activation of p75NTR pathway are involved in denervation-induced inflammation in skeletal muscle. The results suggest that inhibition of pro-BDNF-p75NTR pathway can be a new target to treat skeletal muscle inflammation.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Músculo Esquelético/metabolismo , Receptores de Fator de Crescimento Neural/metabolismo , Animais , Fator Neurotrófico Derivado do Encéfalo/fisiologia , Feminino , Isoleucina/análogos & derivados , Isoleucina/farmacologia , Masculino , Glicoproteínas de Membrana/metabolismo , Glicoproteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Morfolinas/farmacologia , Denervação Muscular/métodos , Músculo Esquelético/fisiologia , Atrofia Muscular/metabolismo , Doenças do Sistema Nervoso Periférico , Precursores de Proteínas/metabolismo , Precursores de Proteínas/fisiologia , Proteínas Tirosina Quinases/metabolismo , Proteínas Tirosina Quinases/fisiologia , Receptores de Fator de Crescimento Neural/fisiologia , Transdução de Sinais/fisiologia
9.
Biochem Biophys Res Commun ; 582: 111-117, 2021 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-34710825

RESUMO

Skeletal muscle is known to regulate bone homeostasis through muscle-bone interaction, although factors that control this activity remain unclear. Here, we newly established Smad3-flox mice, and then generated skeletal muscle-specific Smad2/Smad3 double conditional knockout mice (DcKO) by crossing Smad3-flox with skeletal muscle-specific Ckmm Cre and Smad2-flox mice. We show that immobilization-induced gastrocnemius muscle atrophy occurring due to sciatic nerve denervation was partially but significantly inhibited in DcKO mice, suggesting that skeletal muscle cell-intrinsic Smad2/3 is required for immobilization-induced muscle atrophy. Also, tibial bone atrophy seen after sciatic nerve denervation was partially but significantly inhibited in DcKO mice. Bone formation rate in wild-type mouse tibia was significantly inhibited by immobilization, but inhibition was abrogated in DcKO mice. We propose that skeletal muscle regulates immobilization-induced bone atrophy via Smad2/3, and Smad2/3 represent potential therapeutic targets to prevent both immobilization-induced bone and muscle atrophy.


Assuntos
Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/prevenção & controle , Nervo Isquiático/lesões , Proteína Smad2/genética , Proteína Smad3/genética , Animais , Cruzamentos Genéticos , Feminino , Regulação da Expressão Gênica , Integrases/genética , Integrases/metabolismo , Masculino , Camundongos , Camundongos Knockout , Denervação Muscular/métodos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Proteínas Ligases SKP Culina F-Box/genética , Proteínas Ligases SKP Culina F-Box/metabolismo , Transdução de Sinais , Proteína Smad2/deficiência , Proteína Smad3/deficiência , Tíbia/inervação , Tíbia/metabolismo , Proteínas com Motivo Tripartido/genética , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
10.
Nutrients ; 13(9)2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34578826

RESUMO

Maslinic acid (MA) is a pentacyclic triterpene abundant in olive peels. MA reportedly increases skeletal muscle mass and strength in older adults; however, the underlying mechanism is unknown. This study aimed to investigate the effects of MA on denervated muscle atrophy and strength and to explore the underlying molecular mechanism. Mice were fed either a control diet or a 0.27% MA diet. One week after intervention, the sciatic nerves of both legs were cut to induce muscle atrophy. Mice were examined 14 days after denervation. MA prevented the denervation-induced reduction in gastrocnemius muscle mass and skeletal muscle strength. Microarray gene expression profiling in gastrocnemius muscle demonstrated several potential mechanisms for muscle maintenance. Gene set enrichment analysis (GSEA) revealed different enriched biological processes, such as myogenesis, PI3/AKT/mTOR signaling, TNFα signaling via NF-κB, and TGF-ß signaling in MA-treated mice. In addition, qPCR data showed that MA induced Igf1 expression and suppressed the expressions of Atrogin-1, Murf1 and Tgfb. Altogether, our results suggest the potential of MA as a new therapeutic and preventive dietary ingredient for muscular atrophy and strength.


Assuntos
Força Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Atrofia Muscular/tratamento farmacológico , Triterpenos/farmacologia , Animais , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Denervação Muscular/métodos , Desenvolvimento Muscular/genética , Músculo Esquelético/inervação , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Doenças Musculares/patologia , NF-kappa B/metabolismo , Olea/química , Nervo Isquiático/lesões , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
11.
JCI Insight ; 6(13)2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34128833

RESUMO

Neurogenic muscle atrophy is the loss of skeletal muscle mass and function that occurs with nerve injury and in denervating diseases, such as amyotrophic lateral sclerosis. Aside from prompt restoration of innervation and exercise where feasible, there are currently no effective strategies for maintaining skeletal muscle mass in the setting of denervation. We conducted a longitudinal analysis of gene expression changes occurring in atrophying skeletal muscle and identified growth arrest and DNA damage-inducible A (Gadd45a) as a gene that shows one of the earliest and most sustained increases in expression in skeletal muscle after denervation. We evaluated the role of this induction using genetic mouse models and found that mice lacking GADD45A showed accelerated and exacerbated neurogenic muscle atrophy, as well as loss of fiber type identity. Our genetic analyses demonstrate that, rather than directly contributing to muscle atrophy as proposed in earlier studies, GADD45A induction likely represents a protective negative feedback response to denervation. Establishing the downstream effectors that mediate this protective effect and the pathways they participate in may yield new opportunities to modify the course of muscle atrophy.


Assuntos
Esclerose Lateral Amiotrófica , Proteínas de Ciclo Celular/metabolismo , Retroalimentação Fisiológica , Músculo Esquelético , Atrofia Muscular , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Animais , Atrofia , Modelos Animais de Doenças , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Camundongos , Denervação Muscular/métodos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Atrofia Muscular/fisiopatologia , Fatores de Proteção , Transdução de Sinais
12.
Exp Neurol ; 341: 113717, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33839142

RESUMO

Schwann cells are essential for peripheral nerve regeneration but, over short distances in acellular nerve grafts, extracellular matrix (ECM) molecules can support growth. The ECM molecules are present also on denervated muscle surfaces where they can support nerve growth. In this study, we addressed the efficacy of the ECM molecules of denervated muscle to support nerve fiber regeneration and muscle reinnervation. In the hindlimb of Sprague-Dawley rats, the proximal stump of the transected posterior tibial nerve, was cross-sutured to the distal nerve stump (NN) of each of three denervated muscles, tibialis anterior, extensor digitorum longus, and soleus, or implanted onto the denervated muscles' surfaces (N-M), proximal or distal to the endplate zone. Recordings of muscle and motor unit (MU) isometric forces and silver/cholinesterase histochemical staining of longitudinal muscle cryosections were used to determine the numbers of reinnervated MUs and the spatial course of regenerating nerve fibers, respectively. MU numbers declined significantly after N-M (>50%) as compared to those after NN. Muscle forces were reduced despite each nerve reinnervating up to three times the normal MU muscle fiber number. Regenerating nerves 'streamed' from the N-M site either proximal or distal to endplate zones toward the denervated intramuscular endoneurial tubes, with reduced numbers reinnervating endplates. We conclude that there is preferential reinnervation through the endoneurial tube and that it is important to drive implanted nerve fibers to enter endoneurial tubes for optimal muscle reinnervation. Schwann cells play the essential role in guiding regenerating nerve fibers to reinnervate denervated muscle fibers.


Assuntos
Contração Isométrica/fisiologia , Músculo Esquelético/fisiologia , Regeneração Nervosa/fisiologia , Nervos Periféricos/fisiologia , Recrutamento Neurofisiológico/fisiologia , Animais , Eletromiografia/métodos , Feminino , Denervação Muscular/métodos , Músculo Esquelético/inervação , Ratos , Ratos Sprague-Dawley
13.
Exp Neurol ; 339: 113650, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33607079

RESUMO

Functional recovery following peripheral nerve injury worsens with increasing durations of delay prior to repair. From the time of injury until re-innervation occurs, denervated muscle undergoes progressive atrophy that limits the extent to which motor function can be restored. Similarly, Schwann cells (SC) in the distal nerve lacking axonal interaction progressively lose their capacity to proliferate and support regenerating axons. The relative contributions of these processes to diminished functional recovery is unclear. We developed a novel rat model to isolate the effects of SC vs. muscle denervation on functional recovery. Four different groups underwent the following interventions for 12 weeks prior to nerve transfer: 1) muscle denervation; 2) SC denervation; 3) muscle + SC denervation (negative control); 4) no denervation (positive control). Functional recovery was measured weekly using the stimulated grip strength testing (SGST). Animals were sacrificed 13 weeks post nerve transfer. Retrograde labeling was used to assess the number of motor neurons that regenerated their axons. Immunofluorescence was performed to evaluate target muscle re-innervation and atrophy, and to assess the phenotype of the SC within the distal nerve segment. Functional recovery in the muscle denervation and SC denervation groups mirrored that of the negative and positive control groups, respectively. The SC denervation group achieved better functional recovery, with a greater number of reinnervated motor endplates and less muscle atrophy, than the muscle denervation group. Retrograde labeling suggested a higher number of neurons contributing to muscle reinnervation in the muscle denervation group as compared to SC denervation (p > 0.05). The distal nerve segment in the muscle denervation group had a greater proportion of SCs expressing the proliferation marker Ki67 as compared to the SC denervation group (p < 0.05). Conversely, the SC denervation group had a higher percentage of senescent SCs expressing p16 as compared to the muscle denervation group (p < 0.05). The deleterious effects of muscle denervation are more consequential than the effects of SC denervation on functional recovery. The effects of 12 weeks of SC denervation on functional outcome were negligible. Future studies are needed to determine whether longer periods of SC denervation negatively impact functional recovery.


Assuntos
Nervo Mediano/fisiologia , Denervação Muscular/métodos , Regeneração Nervosa/fisiologia , Recuperação de Função Fisiológica/fisiologia , Células de Schwann/fisiologia , Nervo Ulnar/fisiologia , Animais , Força da Mão/fisiologia , Masculino , Nervo Mediano/transplante , Denervação Muscular/tendências , Atrofia Muscular , Traumatismos dos Nervos Periféricos/patologia , Traumatismos dos Nervos Periféricos/cirurgia , Ratos , Ratos Endogâmicos Lew , Nervo Ulnar/transplante
14.
FEBS Lett ; 595(5): 655-666, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33421114

RESUMO

Neonatal brachial plexus injury (NBPI) causes disabling and incurable muscle contractures that are driven by impaired growth of denervated muscles. A rare form of NBPI, which maintains afferent muscle innervation despite motor denervation, does not cause contractures. As afferent innervation regulates various aspects of skeletal muscle homeostasis through NRG/ErbB signaling, our current study investigated the role of this pathway in modulating contracture development. Through pharmacologic modification with an ErbB antagonist and NRG1 isoforms, we discovered that NRG/ErbB signaling does not modulate the development of contractures in neonatal mice. Instead, ErbB inhibition impeded growth in nondenervated skeletal muscles, whereas increased ErbB activation exacerbated denervation-induced skeletal muscle atrophy. This potential regulatory effect of NRG/ErbB signaling on neonatal muscle growth warrants deeper investigation.


Assuntos
Contratura/genética , Receptores ErbB/genética , Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Neuregulina-1/genética , Animais , Animais Recém-Nascidos , Plexo Braquial/efeitos dos fármacos , Plexo Braquial/lesões , Plexo Braquial/metabolismo , Contratura/metabolismo , Contratura/fisiopatologia , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , Regulação da Expressão Gênica , Camundongos , Morfolinas/farmacologia , Denervação Muscular/métodos , Desenvolvimento Muscular/genética , Músculo Esquelético/citologia , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/inervação , Atrofia Muscular/metabolismo , Atrofia Muscular/fisiopatologia , Neuregulina-1/metabolismo , Junção Neuromuscular/efeitos dos fármacos , Junção Neuromuscular/lesões , Junção Neuromuscular/metabolismo , Transdução de Sinais
15.
J Vasc Interv Radiol ; 31(6): 912-916.e1, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32376178

RESUMO

Eight patients who underwent percutaneous cryoablation of mixed and/or motor nerves over a period of 5 years were identified. Distances from the ablation sites to origins of distal musculature were measured, and times to initial clinical recovery were collected. Strength progression over time following muscle activation was also collected and analyzed. All patients demonstrated activation of all muscles distal to the ablation, and the calculated mean rate of nerve regeneration based on distance to the origin of the assessed musculature and time to muscle activation for the group was 1.5 mm/day ± 1.1.


Assuntos
Criocirurgia , Denervação Muscular/métodos , Força Muscular , Músculo Esquelético/inervação , Regeneração Nervosa , Dor/cirurgia , Traumatismos dos Nervos Periféricos/fisiopatologia , Nervos Periféricos/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Criocirurgia/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios Motores/patologia , Denervação Muscular/efeitos adversos , Dor/diagnóstico , Dor/fisiopatologia , Traumatismos dos Nervos Periféricos/diagnóstico , Traumatismos dos Nervos Periféricos/etiologia , Traumatismos dos Nervos Periféricos/patologia , Nervos Periféricos/patologia , Nervos Periféricos/fisiopatologia , Estudos Prospectivos , Recuperação de Função Fisiológica , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
16.
Cells ; 9(4)2020 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-32268508

RESUMO

The decline in muscle mass and function with age is partly caused by a loss of muscle fibres through denervation. The purpose of this study was to investigate the potential of exercise to influence molecular targets involved in neuromuscular junction (NMJ) stability in healthy elderly individuals. Participants from two studies (one group of 12 young and 12 elderly females and another group of 25 elderly males) performed a unilateral bout of resistance exercise. Muscle biopsies were collected at 4.5 h and up to 7 days post exercise for tissue analysis and cell culture. Molecular targets related to denervation and NMJ stability were analysed by immunohistochemistry and real-time reverse transcription polymerase chain reaction. In addition to a greater presence of denervated fibres, the muscle samples and cultured myotubes from the elderly individuals displayed altered gene expression levels of acetylcholine receptor (AChR) subunits. A single bout of exercise induced general changes in AChR subunit gene expression within the biopsy sampling timeframe, suggesting a sustained plasticity of the NMJ in elderly individuals. These data support the role of exercise in maintaining NMJ stability, even in elderly inactive individuals. Furthermore, the cell culture findings suggest that the transcriptional capacity of satellite cells for AChR subunit genes is negatively affected by ageing.


Assuntos
Envelhecimento/fisiologia , Exercício Físico/fisiologia , Denervação Muscular/métodos , Fibras Musculares Esqueléticas/fisiologia , Junção Neuromuscular/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
J Musculoskelet Neuronal Interact ; 20(1): 114-120, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-32131375

RESUMO

OBJECTIVES: In the skeletal muscles, water metabolism is mainly regulated by water channel aquaporin 4 (AQP4). Although the expression level of AQP4 was reduced by long-term denervation, during denervation the relationship between muscle atrophy initiation and AQP4 expression decrease initiation remains unknown. The present study examined the relationship between the timing of muscle atrophy initiation and that of AQP4 expression decrease initiation, during the early stage of denervation. METHODS: Female 344 rats (8 weeks of age) were randomly assigned to control (C), day 1 post-sciatic denervation (D1), day 4 post- sciatic denervation (D4) and day 7 post- sciatic denervation (D7) groups (n=6 per group). In the tibialis anterior (TA) muscles of each group, the expression levels of some target proteins were quantified by Western blot analysis. RESULTS: The expression level of AQP4 significantly decreased on day 4 post-denervation (p<0.05). Moreover, the beginning of the decrease in AQP4 expression level was concurrent with the timing of muscle atrophy in the skeletal muscles during the early stage of denervation. CONCLUSIONS: The present study suggested that the progression of the decrease in the AQP4 expression level is partly related to the progression of muscle atrophy during the early stage of denervation.


Assuntos
Aquaporina 4/biossíntese , Denervação Muscular/tendências , Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Animais , Aquaporina 4/genética , Feminino , Expressão Gênica , Denervação Muscular/métodos , Músculo Esquelético/patologia , Atrofia Muscular/patologia , Ratos , Ratos Endogâmicos F344 , Fatores de Tempo
18.
Life Sci ; 248: 117465, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32105707

RESUMO

BACKGROUND: Severe peripheral nerve injury leads to skeletal muscle atrophy and impaired limb function that is not sufficiently improved by existing treatments. Fibroblast growth factor 6 (FGF6) is involved in tissue regeneration and is dysregulated in denervated rat muscles. However, the way that FGF6 affects skeletal muscle repair after peripheral nerve injury has not been fully elucidated. METHODS: In this study, we investigated the role of FGF6 in the regeneration of denervated muscles using myoblast cells and an in vivo model of peripheral nerve injury. RESULTS: FGF6 promoted the viability and migration of C2C12 and primary myoblasts in a dose-dependent manner through FGFR1-mediated upregulation of cyclin D1. Low concentrations of FGF6 promoted myoblast differentiation through FGFR4-mediated activation of ERK1/2, which upregulated expression of MyHC, MyoD, and myogenin. FGFR-1, FGFR4, MyoD, and myogenin were not upregulated when FGF6 expression was inhibited in myoblasts by shRNA-mediated knockdown. Injection of FGF6 into denervated rat muscles enhanced the MyHC-IIb muscle fiber phenotype and prevented muscular atrophy. CONCLUSION: These findings indicate that FGF6 reduces skeletal muscle atrophy by relying on the ERK1/2 mechanism and enhances the conversion of slow muscle to fast muscle fibers, thereby promoting functional recovery of regenerated skeletal muscle after innervation.


Assuntos
Fator 6 de Crescimento de Fibroblastos/genética , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/genética , Músculo Esquelético/metabolismo , Traumatismos dos Nervos Periféricos/genética , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/genética , Regeneração/genética , Animais , Diferenciação Celular , Linhagem Celular , Movimento Celular , Proliferação de Células , Ciclina D1/genética , Ciclina D1/metabolismo , Fator 6 de Crescimento de Fibroblastos/antagonistas & inibidores , Fator 6 de Crescimento de Fibroblastos/metabolismo , Regulação da Expressão Gênica , Masculino , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Denervação Muscular/métodos , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Proteína MyoD/genética , Proteína MyoD/metabolismo , Mioblastos/metabolismo , Mioblastos/patologia , Miogenina/genética , Miogenina/metabolismo , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Cultura Primária de Células , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor Tipo 1 de Fator de Crescimento de Fibroblastos/metabolismo , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 4 de Fator de Crescimento de Fibroblastos/metabolismo , Nervo Isquiático/lesões
19.
FEBS J ; 287(1): 73-93, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31545558

RESUMO

Physiological or pathological muscle disuse/inactivity or loss of the neural-muscular junction cause muscle atrophy. Atrophy-inducing conditions cause metabolic oxidative stress in the muscle tissue, activation of the ubiquitin-proteasome and of the autophagosome-lysosome systems, enhanced removal of the damaged proteins and organelles, and loss of muscle mass and strength. The signaling pathways that control these catabolic processes are only partially known. In this study, we systematically analyzed the role of p38α mitogen-activated protein kinase (MAPK) in denervation-mediated atrophy. Mice with attenuated activity of p38α (p38AF ) are partially protected from muscle damage and atrophy. Denervated (Den) muscles of these mutant mice exhibit reduced signs of oxidative stress, decreased unfolded protein response and lower levels of ubiquitinated proteins relative to Den muscles of control mice. Further, whereas autopahagy flux is inhibited in Den muscles of control mice, Den muscles of p38AF mice maintain normal level of autophagy flux. Last, muscle denervation affects differently the energy metabolism of muscles in normal and mutant mice; whereas denervation appears to increase mitochondrial oxidative metabolism in control mice, it elevates anaerobic glycolytic metabolism in p38AF mice. Our results indicate, therefore, that attenuation of p38α activity in mice protects Den muscles by reducing oxidative stress, lowering protein damage and improving the clearance of damaged mitochondria by autophagy.


Assuntos
Autofagia , Redes e Vias Metabólicas , Proteína Quinase 14 Ativada por Mitógeno/fisiologia , Denervação Muscular/métodos , Músculo Esquelético/patologia , Atrofia Muscular/patologia , Estresse Oxidativo , Animais , Feminino , Lisossomos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Músculo Esquelético/inervação , Músculo Esquelético/metabolismo , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Transdução de Sinais , Ubiquitina/metabolismo
20.
Reg Anesth Pain Med ; 45(1): 79-83, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31831629

RESUMO

In 2017, JAMA: Journal of the American Medical Association published the results of the MINT trials, prospective research involving 681 patients, all of whom received exercise therapy for low back pain. Half of the patients were randomized to additionally receive radiofrequency denervation (RFD) treatment. 88% of patients completed the 3-month follow-up, and 77% completed the 12-month follow-up. In this context, RFD provided no added benefit over the baseline of exercise therapy. In 2018, five authors, all experts in pain medicine, published a 'Daring Discourse' article in the journal Regional Anesthesia and Pain Medicine (RAPM), criticizing the findings of the MINT trials. Although 3 of the 5 authors of the RAPM 'Daring Discourse' article reported in conflict of interest statements-as is appropriate-that they were consultants to corporations that produce RFD equipment, the authors failed to disclose that 4 of 5 are on the editorial board of RAPM and all 5 are current officers in the medical organization that owns RAPM: that is, the American Society of Regional Anesthesia and Pain Medicine. Noteworthy, there was no published response from the MINT trial investigators to the Daring Discourse criticisms, either in the aforementioned example or in downstream venues where some of the same Daring Discourse authors continued their widely disseminated criticisms of the JAMA/MINT trials report. We believe that these actions taken by the Daring Discourse authors and RAPM have unfairly tipped the scales in the evaluation and application of RFD treatment of low back pain. In our commentary, we discuss: (1) the challenges associated with using clinical trials to predict clinical efficacy, (2) appropriate and inappropriate uses of postpublication commentary on original research findings, (3) the use of inappropriate commentary (and related means) to alter clinical practice in the presence of contradictory research findings, and (4) potential conflicts of interest related to the authors' and Journal's publication of the unopposed MINT trials criticism.


Assuntos
Medicina Baseada em Evidências/normas , Dor Lombar/terapia , Denervação Muscular/normas , Defesa do Paciente/normas , Terapia por Radiofrequência/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/normas , Medicina Baseada em Evidências/métodos , Humanos , Dor Lombar/diagnóstico , Dor Lombar/epidemiologia , Denervação Muscular/métodos , Terapia por Radiofrequência/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Resultado do Tratamento
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