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1.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 42(5): 640-645, 2020 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-33131519

RESUMO

Objective To explore the value of contrast-enhanced ultrasound(CEUS)in the detection of peripheral nerve crush injury.Methods Thirty New Zealand white rabbits were randomly divided into normal control group and sciatic nerve crush injury group(which included 3-day,2-week,4-week,and 8-week groups after operation).The morphological structure and blood perfusion of the injured sciatic nerves were detected by high-frequency ultrasound,power Doppler ultrasound(PDUS),CEUS,and histopathology.Results Conventional ultrasound revealed that the internal diameter of nerves showed no significant difference between the 8-week group and the control group [(1.14±0.15)mm vs.(0.92±0.11)mm;t=4.72,P=0.86].Analysis of nerve blood perfusion showed that PDUS had a high sensitivity in displaying fine blood flow signal inside the injured nerve in the acute stage of inflammation(3-day group)but not good enough in the 4-and 8-week groups.CEUS could clearly show the microcirculation perfusion in the 3-day,2-week,4-week,and 8-week groups,and analyses of the area under the curve,the peak time,and the peak intensity showed that the nerve blood perfusion increased significantly 3 days after operation and then decreased gradually.Histopathological examination showed that the median cumulative OD value was 12 035.6(10 566.3,14 805.8)8 weeks after operation,which was still significantly lower than that 18 784.8(15 904.5,21 103.5)in the normal control group(H=6.10, P=0.0003).Conclusions Conventional high-frequency ultrasound and PDUS can not adequately evaluate the microcirculation perfusion in different periods after nerve injury.CEUS can quantitatively evaluate the microvascular perfusion of injured nerve at any period and provide more information for indirect evaluation of nerve regeneration.


Assuntos
Meios de Contraste , Lesões por Esmagamento , Traumatismos dos Nervos Periféricos , Ultrassonografia , Animais , Meios de Contraste/normas , Lesões por Esmagamento/diagnóstico por imagem , Microcirculação , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/diagnóstico por imagem , Traumatismos dos Nervos Periféricos/patologia , Coelhos , Distribuição Aleatória , Nervo Isquiático/diagnóstico por imagem , Nervo Isquiático/lesões , Nervo Isquiático/patologia
2.
PLoS One ; 15(11): e0240911, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33211695

RESUMO

PURPOSE: The treatment strategy is different for acute traumatic peripheral nerve injury and acute compressive neuropathy. This study aimed to compare magnetic resonance imaging (MRI) features of acute traumatic peripheral nerve injury and acute compressive neuropathy in a rat model. MATERIALS AND METHODS: Twenty female Sprague-Dawley rats were divided into two groups. In the crush injury group (n = 10), the unilateral sciatic nerve was crushed using forceps to represent acute traumatic peripheral nerve injury. In the compression injury group (n = 10), the unilateral sciatic nerve was ligated using silk to represent acute compressive neuropathy. The MRI of eight rats from each group were acquired on postoperative days 3 and 10. Fat-suppressed T2-weighted images were acquired. Changes in the injured nerve were divided into three grades. A Fisher's exact test was used to compare the changes in the nerves of the two groups. Histological staining and a western blot analysis were performed on one rat in each group on day 3. Neurofilament, myelin basic protein (MBP), and p75NTR staining were performed. Expression of neurofilament, MBP, p75NTR, and c-jun was evaluated by western blot analysis. RESULTS: MR neurography revealed substantial nerve changes in the compression injury group compared with the crush injury group at two-time points (p = 0.001 on day 3, p = 0.026 on day 10). The histopathological analysis indicated the destruction of the axon and myelin, mainly at the injury site and the distal portion of the injury in the crush injury group. It was prominent in the proximal portion, the injury site, and the distal portion of the injury in the compression injury group. The degree of axonal and myelin destruction was more pronounced in the compression injury group than in the crush injury group. CONCLUSION: MR neurography showed prominent and long-segmental changes associated with the injured nerve in acute compressive neuropathy compared with acute traumatic peripheral nerve injury.


Assuntos
Síndromes de Compressão Nervosa/diagnóstico por imagem , Traumatismos dos Nervos Periféricos/diagnóstico por imagem , Doença Aguda , Animais , Lesões por Esmagamento/diagnóstico por imagem , Lesões por Esmagamento/metabolismo , Lesões por Esmagamento/patologia , Modelos Animais de Doenças , Feminino , Imagem por Ressonância Magnética/métodos , Síndromes de Compressão Nervosa/metabolismo , Síndromes de Compressão Nervosa/patologia , Degeneração Neural/diagnóstico por imagem , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Proteínas do Tecido Nervoso/metabolismo , Traumatismos dos Nervos Periféricos/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
3.
J Vis Exp ; (164)2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33104075

RESUMO

Peripheral and central nerve injuries are mostly studied in rodents, especially rats, given the fact that these animal models are both cost-effective and a lot of comparative data has been published in the literature. This includes a multitude of assessment methods to study functional recovery following nerve injury and repair. Besides evaluation of nerve regeneration by means of histology, electrophysiology, and other in vivo and in vitro assessment techniques, functional recovery is the most important criterion to determine the degree of neural regeneration. Automated gait analysis allows recording of a vast quantity of gait-related parameters such as Paw Print Area and Paw Swing Speed as well as measures of inter-limb coordination. Additionally, the method provides digital data of the rats' paws after neuronal damage and during nerve regeneration, adding to our understanding of how peripheral and central nervous injuries affect their locomotor behavior. Besides the predominantly used sciatic nerve injury model, other models of peripheral nerve injury such as the femoral nerve can be studied by means of this method. In addition to injuries of the peripheral nervous systems, lesions of the central nervous system, e.g., spinal cord contusion can be evaluated. Valid and reproducible data assessment is strongly dependent on meticulous adjustment of the hard- and software settings prior to data acquisition. Additionally, proper training of the experimental animals is of crucial importance. This work aims to illustrate the use of computerized automated gait analysis to assess functional recovery in different animal models of peripheral nerve injury as well as spinal cord contusion injury. It also emphasizes the method's limitations, e.g., evaluation of nerve regeneration in rats with sciatic nerve neurotmesis due to limited functional recovery. Therefore, this protocol is thought to help researchers interested in peripheral and central nervous injuries to assess functional recovery in rodent models.


Assuntos
Análise da Marcha/métodos , Traumatismos dos Nervos Periféricos/fisiopatologia , Recuperação de Função Fisiológica/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Animais , Autoenxertos , Automação , Modelos Animais de Doenças , Nervo Femoral/patologia , Nervo Femoral/fisiopatologia , Marcha/fisiologia , Membro Posterior/fisiopatologia , Abrigo para Animais , Masculino , Regeneração Nervosa/fisiologia , Ratos Endogâmicos Lew , Ratos Sprague-Dawley , Nervo Isquiático/patologia , Nervo Isquiático/fisiopatologia , Neuropatia Ciática/fisiopatologia , Vértebras Torácicas/patologia , Vértebras Torácicas/fisiopatologia
4.
PLoS One ; 15(9): e0238208, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32881928

RESUMO

INTRODUCTION: Peripheral nerve injury (PNI) often leads to significant functional loss in patients and poses a challenge to physicians since treatment options for improving functional outcomes are limited. Recent studies suggest that erythropoietin and glucocoticoids have beneficial effects as mediators of neuro-regenerative processes. We hypothesized that combination treatment with erythropoietin and glucocoticoids would have a synergistic effect on functional outcome after PNI. MATERIALS AND METHODS: Sciatic nerve crush injury was simulated in ten-week-old male C57BL/6 mice. The mice were divided into four groups according to the type of drugs administered (control, erythropoietin, dexamethasone, and erythropoietin with dexamethasone). Motor functional recovery was monitored by walking track analysis at serial time points up to 28 days after injury. Morphological analysis of the nerve was performed by immunofluorescent staining for neurofilament (NF) heavy chain and myelin protein zero (P0) in cross-sectional and whole-mount nerve preparations. Additionally, morphological analysis of the muscle was performed by Hematoxylin and eosin staining. RESULTS: Combination treatment with erythropoietin and dexamethasone significantly improved the sciatic functional index at 3, 7, 14, and 28 days after injury. Fluorescence microscopy of cross sectional nerve revealed that the combination treatment increased the ratio of P0/NF-expressing axons. Furthermore, confocal microscopy of the whole-mount nerve revealed that the combination treatment increased the fluorescence intensity of P0 expression. The cross-sectional area and minimum Feret's diameter of the muscle fibers were significantly larger in the mice which received combination treatment than those in the controls. CONCLUSION: Our results demonstrated that combination treatment with erythropoietin and dexamethasone accelerates functional recovery and reduces neurogenic muscle atrophy caused by PNI in mice, which may be attributed to the preservation of myelin and Schwann cell re-myelination. These findings may provide practical therapeutic options for patients with acute PNI.


Assuntos
Dexametasona/uso terapêutico , Eritropoetina/uso terapêutico , Músculos/metabolismo , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Nervo Isquiático/metabolismo , Doença Aguda , Animais , Axônios/metabolismo , Dexametasona/farmacologia , Modelos Animais de Doenças , Quimioterapia Combinada , Eritropoetina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Músculos/patologia , Atrofia Muscular/patologia , Atrofia Muscular/prevenção & controle , Proteína P0 da Mielina/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Recuperação de Função Fisiológica/efeitos dos fármacos , Remielinização/efeitos dos fármacos , Células de Schwann/citologia , Células de Schwann/metabolismo , Nervo Isquiático/patologia
5.
Nat Metab ; 2(9): 918-933, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32778834

RESUMO

Regeneration after injury occurs in axons that lie in the peripheral nervous system but fails in the central nervous system, thereby limiting functional recovery. Differences in axonal signalling in response to injury that might underpin this differential regenerative ability are poorly characterized. Combining axoplasmic proteomics from peripheral sciatic or central projecting dorsal root ganglion (DRG) axons with cell body RNA-seq, we uncover injury-dependent signalling pathways that are uniquely represented in peripheral versus central projecting sciatic DRG axons. We identify AMPK as a crucial regulator of axonal regenerative signalling that is specifically downregulated in injured peripheral, but not central, axons. We find that AMPK in DRG interacts with the 26S proteasome and its CaMKIIα-dependent regulatory subunit PSMC5 to promote AMPKα proteasomal degradation following sciatic axotomy. Conditional deletion of AMPKα1 promotes multiple regenerative signalling pathways after central axonal injury and stimulates robust axonal growth across the spinal cord injury site, suggesting inhibition of AMPK as a therapeutic strategy to enhance regeneration following spinal cord injury.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Axônios , Gânglios Espinais/metabolismo , Regeneração Nervosa , Células Receptoras Sensoriais/metabolismo , Traumatismos da Medula Espinal/metabolismo , ATPases Associadas a Diversas Atividades Celulares/metabolismo , Animais , Transporte Axonal , Axotomia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Feminino , Gânglios Espinais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteômica , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia , Células Receptoras Sensoriais/patologia , Traumatismos da Medula Espinal/patologia
6.
PLoS One ; 15(8): e0237101, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817686

RESUMO

Mutations in the genes encoding for voltage-gated sodium channels cause profound sensory disturbances and other symptoms dependent on the distribution of a particular channel subtype in different organs. Humans with the gain-of-function mutation p.Leu811Pro in SCN11A (encoding for the voltage-gated Nav1.9 channel) exhibit congenital insensitivity to pain, pruritus, self-inflicted injuries, slow healing wounds, muscle weakness, Charcot-like arthropathies, and intestinal dysmotility. As already shown, knock-in mice (Scn11a+/L799P) carrying the orthologous mutation p.Leu799Pro replicate reduced pain sensitivity and show frequent tissue lesions. In the present study we explored whether Scn11a+/L799P mice develop also pruritus, muscle weakness, and changes in gastrointestinal transit time. Furthermore, we analyzed morphological and functional differences in nerves, skeletal muscle, joints and small intestine from Scn11a+/L799P and Scn11a+/+ wild type mice. Compared to Scn11a+/+ mice, Scn11a+/L799P mice showed enhanced scratching bouts before skin lesions developed, indicating pruritus. Scn11a+/L799P mice exhibited reduced grip strength, but no disturbances in motor coordination. Skeletal muscle fiber types and joint architecture were unaltered in Scn11a+/L799P mice. Their gastrointestinal transit time was unaltered. The small intestine from Scn11a+/L799P showed a small shift towards less frequent peristaltic movements. Similar proportions of lumbar dorsal root ganglion neurons from Scn11a+/L799P and Scn11a+/+ mice were calcitonin gene-related peptide (CGRP-) positive, but isolated sciatic nerves from Scn11a+/L799P mice exhibited a significant reduction of the capsaicin-evoked release of CGRP indicating reduced neurogenic inflammation. These data indicate important Nav1.9 channel functions in several organs in both humans and mice. They support the pathophysiological relevance of increased basal activity of Nav1.9 channels for sensory abnormalities (pain and itch) and suggest resulting malfunctions of the motor system and of the gastrointestinal tract. Scn11a+/L799P mice are suitable to investigate the role of Nav1.9, and to explore the pathophysiological changes and mechanisms which develop as a consequence of Nav1.9 hyperactivity.


Assuntos
Mutação com Ganho de Função , Debilidade Muscular/genética , Canal de Sódio Disparado por Voltagem NAV1.9/genética , Prurido/genética , Animais , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Feminino , Trânsito Gastrointestinal , Força da Mão , Intestino Delgado/metabolismo , Intestino Delgado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Movimento , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Canal de Sódio Disparado por Voltagem NAV1.9/metabolismo , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
7.
Chem Biol Interact ; 330: 109232, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32860822

RESUMO

Currently, whether nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation contributes to neuropathy induced by 2,5-Hexanedione (HD), the toxic metabolite of n-hexane, remains unknown. In this study, we found that HD intoxication elevated NLRP3 expression, caspase-1 activation and interleukin-1ß production in sciatic nerve of rats, indicating activation of NLRP3 inflammasome. The increased cleavage of gasdermin D (GSDMD) protein, an important mediator of pyroptosis, and axon degeneration were also observed in sciatic nerves of HD-intoxicated rats. Interestingly, glybenclamide, a widely used inhibitor of NLRP3 inflammasome, significantly reduced NLRP3 inflammasome activation, which was associated with decreased GSDMD cleavage and axon degeneration as well as improved motor performance of HD-intoxicated rats. Subsequently, we found that inhibition of NLRP3 inflammasome by glybenclamide attenuated macrophage infiltration, activation and M1 polarization in sciatic nerves of HD-intoxicated rats. Furthermore, decreased malondialdehyde (MDA) contents and increased glutathione (GSH) level and total anti-oxidative capacity were also observed in sciatic nerves of rats treated with combined glybenclamide and HD compared with HD alone group. Altogether, our findings suggest that NLRP3 inflammasome activation contributes to HD-induced neurotoxicity by enhancing macrophage infiltration and activation as well as oxidative stress, providing a novel mechanism of neuropathy induced by this neurotoxicant.


Assuntos
Hexanonas/toxicidade , Macrófagos/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/farmacologia , Síndromes Neurotóxicas/etiologia , Animais , Antioxidantes/metabolismo , Movimento Celular/efeitos dos fármacos , Glutationa/metabolismo , Glibureto/farmacologia , Inflamassomos/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Síndromes Neurotóxicas/tratamento farmacológico , Estresse Oxidativo , Proteínas de Ligação a Fosfato/metabolismo , Piroptose , Ratos , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia
8.
Eur. j. anat ; 24(4): 281-284, jul. 2020. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-193961

RESUMO

Severe hamstring injuries warranting surgical repair are rare and mainly affect athletes, young and middle-aged people. A minority of these patients report postoperative complications of denervation. Symptoms of denervation range from muscle weakness to sciatic nerve palsy. Recent anatomical observations suggest that a recurrent motor nerve, which inserts into the proximal ham-strings, may be responsible for this denervation. The recurrent motor nerve was identified through cadaveric dissection and the site of nerve penetration into the muscle, measured 1.5 cm from the ischial tuberosity. This distance is significantly shorter than previous studies report. Awareness of this nerve branch is an important consideration in hamstring injury and repair. Due to its course, the recurrent motor nerve’s name is also a source of discussion


No disponible


Assuntos
Humanos , Nervo Isquiático/anatomia & histologia , Denervação/métodos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/inervação , Cadáver , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Nervos Periféricos/anatomia & histologia
9.
J Biol Chem ; 295(31): 10807-10821, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32532796

RESUMO

In the peripheral nerve, mechanosensitive axons are insulated by myelin, a multilamellar membrane formed by Schwann cells. Here, we offer first evidence that a myelin degradation product induces mechanical hypersensitivity and global transcriptomics changes in a sex-specific manner. Focusing on downstream signaling events of the functionally active 84-104 myelin basic protein (MBP(84-104)) fragment released after nerve injury, we demonstrate that exposing the sciatic nerve to MBP(84-104) via endoneurial injection produces robust mechanical hypersensitivity in female, but not in male, mice. RNA-seq and systems biology analysis revealed a striking sexual dimorphism in molecular signatures of the dorsal root ganglia (DRG) and spinal cord response, not observed at the nerve injection site. Mechanistically, intra-sciatic MBP(84-104) induced phospholipase C (PLC)-driven (females) and phosphoinositide 3-kinase-driven (males) phospholipid metabolism (tier 1). PLC/inositol trisphosphate receptor (IP3R) and estrogen receptor co-regulation in spinal cord yielded Ca2+-dependent nociceptive signaling induction in females that was suppressed in males (tier 2). IP3R inactivation by intrathecal xestospongin C attenuated the female-specific hypersensitivity induced by MBP(84-104). According to sustained sensitization in tiers 1 and 2, T cell-related signaling spreads to the DRG and spinal cord in females, but remains localized to the sciatic nerve in males (tier 3). These results are consistent with our previous finding that MBP(84-104)-induced pain is T cell-dependent. In summary, an autoantigenic peptide endogenously released in nerve injury triggers multisite, sex-specific transcriptome changes, leading to neuropathic pain only in female mice. MBP(84-104) acts through sustained co-activation of metabolic, estrogen receptor-mediated nociceptive, and autoimmune signaling programs.


Assuntos
Sinalização do Cálcio , Gânglios Espinais/metabolismo , Neuralgia/metabolismo , RNA-Seq , Nervo Isquiático/metabolismo , Caracteres Sexuais , Transcriptoma , Animais , Feminino , Gânglios Espinais/patologia , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Camundongos , Proteína Básica da Mielina/toxicidade , Neuralgia/induzido quimicamente , Neuralgia/patologia , Fragmentos de Peptídeos/toxicidade , Nervo Isquiático/patologia , Fosfolipases Tipo C/metabolismo
10.
PLoS One ; 15(6): e0234691, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555658

RESUMO

BACKGROUND: Therapeutic ultrasound (US) is a promising physical therapy modality for peripheral nerve regeneration. However, it is necessary to identify the most effective US parameters and clarify the underlying mechanisms before its clinical application. The intensity of US is one of the most important parameters. However, the optimum intensity for the promotion of peripheral nerve regeneration has yet to be determined. OBJECTIVES: To identify the optimum intensity of US necessary for the promotion of peripheral nerve regeneration after crush injuries in rats and to clarify the underlying mechanisms of US by mRNA expression analysis. METHODS: We inflicted sciatic nerve crush injuries on adult Lewis rats and performed ultrasound irradiation using 4 different US intensities: 0 (sham stimulation), 30, 140, and 250 mW/cm2 with frequency (5 days/week) and duration (5 min/day). We evaluated peripheral nerve regeneration by quantitative real-time PCR one week after injury. Histomorphometric analyses and motor function analysis were evaluated 3 weeks after injury. RESULTS: US stimulation enhanced re-myelination as well as sprouting of axons, especially at an intensity of 140 mW/cm2. mRNA expression revealed that US suppressed the expression of the inflammatory cytokines TNF and IL-6 and the axonal growth inhibitors SEMA3A and GSK3ß. CONCLUSIONS: An intensity of 140 mW/cm2 was optimal to support regeneration of the sciatic nerve after a crush injury in rats by, in part, the suppression of pro-inflammatory and nerve growth inhibitor gene expression.


Assuntos
Regulação da Expressão Gênica , Glicogênio Sintase Quinase 3 beta/genética , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/fisiopatologia , Traumatismos dos Nervos Periféricos/terapia , Semaforina-3A/genética , Terapia por Ultrassom , Animais , Citocinas/metabolismo , Glicogênio Sintase Quinase 3 beta/metabolismo , Mediadores da Inflamação/metabolismo , Masculino , Bainha de Mielina/metabolismo , Compressão Nervosa , Regeneração Nervosa/genética , Traumatismos dos Nervos Periféricos/diagnóstico por imagem , Traumatismos dos Nervos Periféricos/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Endogâmicos Lew , Nervo Isquiático/lesões , Nervo Isquiático/patologia , Nervo Isquiático/fisiopatologia , Nervo Isquiático/ultraestrutura , Semaforina-3A/metabolismo
11.
Life Sci ; 256: 117959, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32531375

RESUMO

Resveratrol has the ability to promote functional recovery after sciatic nerve crush injury (SNCI), though the mechanism through which this occurs in not fully understood. Resveratrol can promote autophagy, a key process in Wallerian degeneration; thus, we hypothesized that resveratrol could promote recovery from SNCI by promoting Schwann cell autophagy and acceleration of Wallerian degeneration. Motor function recovery was assessed by calculating Sciatic Function Indexes (SFIs) at days 7, 14, 21, 28 post SNCI. Autophagy and myelin clearance were assessed by microtubule-associated protein light chain 3B (LC3B) and myelin protein zero (MPZ) immunofluorescence and Western blot analysis on the fourth day after SNCI. The autophagy of Schwann cells following resveratrol administration was quantified by immunofluorescence in RSC96 cells. Immunofluorescence and Transmission electron microscopy (TEM) were also used in Resveratrol treated sciatic nerve four days post-SNCI to find LC3B positive areas and typical double membrane structures represent for autophagy. The SNCI+resveratrol (crush+Res) groups recovered faster than the SNCI+vehicles (crush+V) group. On day four, almost all of the myelin had regenerated in the crush+Res rats, while the crush+V group's myelin remained intact and the expression levels of LC3-II/I was the highest. On day 28 post-injury, both the control and crush+Res groups' myelin neurofibers reached peak numbers as did the thickness of the myelin sheath. Both in vitro and in vivo immunofluorescence showed that LC3B was colocalized with Schwann cells. This is the first study to observe that resveratrol can promote recovery from SCNI by accelerating the myelin clearance process by promoting autophagy of Schwann cells.


Assuntos
Autofagia/efeitos dos fármacos , Lesões por Esmagamento/fisiopatologia , Compressão Nervosa , Recuperação de Função Fisiológica/efeitos dos fármacos , Resveratrol/farmacologia , Células de Schwann/patologia , Nervo Isquiático/patologia , Nervo Isquiático/fisiopatologia , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Lesões por Esmagamento/patologia , Masculino , Proteínas Associadas aos Microtúbulos/metabolismo , Atividade Motora/efeitos dos fármacos , Proteína P0 da Mielina/metabolismo , Bainha de Mielina/efeitos dos fármacos , Bainha de Mielina/metabolismo , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/patologia , Regeneração Nervosa/efeitos dos fármacos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Células de Schwann/efeitos dos fármacos , Células de Schwann/metabolismo , Nervo Isquiático/efeitos dos fármacos
12.
World Neurosurg ; 140: 4-9, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32407922

RESUMO

BACKGROUND: Adipose lesions of nerve are generally distinguished as either extraneural or intraneural lipomas or, alternatively, lipomatosis of nerve. We present a patient with an unusual circumferential lipoma that completely encircles the right sciatic nerve and discuss a possible pathogenesis. CASE DESCRIPTION: A 44-year-old woman presented with progressive symptoms and signs of sciatic neuropathy for 1 year. Magnetic resonance imaging revealed a large lipomatous mass extending from the level of the lesser trochanter to the distal third of the femur. The sciatic nerve was completely enveloped by the lipoma in the proximal segment, partially enveloped in the mid-segment and was separate from the nerve in the distal segment. The lipoma was not covered by the epineurium. The tumor was completely resected and the patient's neurologic symptoms improved. CONCLUSIONS: The pathogenetic mechanism of the reported circumferential lipoma of the sciatic nerve is not known. Two possible mechanisms considered included 1) envelopment by an extraneural lipoma over time and 2) occurrence of a lipoma in the paraneurial compartment (and in this case, extension into an extraneural one). Based on the available literature, lipomas that circumferentially envelop the entire nerve seem to be underrecognized and poorly understood. Analogous cases of lipomas enveloping nerves or other structures than nerves have been reported in the literature. Our reported case highlights the complexity of adipose lesions affecting nerves.


Assuntos
Lipoma/patologia , Nervo Isquiático/patologia , Adulto , Feminino , Humanos , Lipoma/cirurgia , Nervo Isquiático/cirurgia
13.
Int J Mol Sci ; 21(7)2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32235682

RESUMO

We evaluated the mechanisms underlying the spinal cord stimulation (SCS)-induced analgesic effect on neuropathic pain following spared nerve injury (SNI). On day 3 after SNI, SCS was performed for 6 h by using electrodes paraspinally placed on the L4-S1 spinal cord. The effects of SCS and intraperitoneal minocycline administration on plantar mechanical sensitivity, microglial activation, and neuronal excitability in the L4 dorsal horn were assessed on day 3 after SNI. The somatosensory cortical responses to electrical stimulation of the hind paw on day 3 following SNI were examined by using in vivo optical imaging with a voltage-sensitive dye. On day 3 after SNI, plantar mechanical hypersensitivity and enhanced microglial activation were suppressed by minocycline or SCS, and L4 dorsal horn nociceptive neuronal hyperexcitability was suppressed by SCS. In vivo optical imaging also revealed that electrical stimulation of the hind paw-activated areas in the somatosensory cortex was decreased by SCS. The present findings suggest that SCS could suppress plantar SNI-induced neuropathic pain via inhibition of microglial activation in the L4 dorsal horn, which is involved in spinal neuronal hyperexcitability. SCS is likely to be a potential alternative and complementary medicine therapy to alleviate neuropathic pain following nerve injury.


Assuntos
Microglia/patologia , Neuralgia/terapia , Traumatismos dos Nervos Periféricos/terapia , Nervo Isquiático/lesões , Estimulação da Medula Espinal , Animais , Masculino , Neuralgia/patologia , Traumatismos dos Nervos Periféricos/patologia , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/patologia , Estimulação da Medula Espinal/métodos
14.
Artigo em Inglês | MEDLINE | ID: mdl-32233950

RESUMO

Homeobox A9 (HOXA9), the expression of which is promoted by mixed lineage leukemia 1 (MLL1) and WD-40 repeat protein 5 (WDR5), is a homeodomain-containing transcription factor that plays an essential role in regulating stem cell activity. HOXA9 has been found to inhibit skeletal muscle regeneration and delay recovery after muscle wounding in aged mice, but little is known about its role in denervated/reinnervated muscles. We performed detailed time-dependent expression analyses of HOXA9 and its promoters, MLL1 and WDR5, in rat gastrocnemius muscles after the following three types of sciatic nerve surgeries: nerve transection (denervation), end-to-end repair (repair), and sham operation (sham). Then, the specific mechanisms of HOXA9 were detected in vitro by transfecting primary satellite cells with empty pIRES2-DsRed2, pIRES2-DsRed2-HOXA9, empty pPLK/GFP-Puro, and pPLK/GFP-Puro-HOXA9 small hairpin RNA (shRNA) plasmids. We found, for the first time, that HOXA9 protein expression simultaneously increased with increasing denervated muscle atrophy severity and that upregulated MLL1 and WDR5 expression was partly associated with denervation. Indeed, in vitro experiments revealed that HOXA9 inhibited myogenic differentiation, affected the best known atrophic signaling pathways, and promoted apoptosis but did not eliminate the differentiation potential of primary satellite cells. HOXA9 may promote denervated muscle atrophy by regulating the activity of satellite cells.


Assuntos
Proteínas de Homeodomínio/metabolismo , Desenvolvimento Muscular , Músculo Esquelético/inervação , Atrofia Muscular/metabolismo , Regeneração Nervosa , Células Satélites de Músculo Esquelético/metabolismo , Nervo Isquiático/cirurgia , Animais , Animais Recém-Nascidos , Apoptose , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Regulação da Expressão Gênica , Membro Posterior , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Proteínas de Homeodomínio/genética , Masculino , Denervação Muscular , Atrofia Muscular/genética , Atrofia Muscular/patologia , Atrofia Muscular/fisiopatologia , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Ratos Sprague-Dawley , Células Satélites de Músculo Esquelético/patologia , Nervo Isquiático/metabolismo , Nervo Isquiático/patologia , Transdução de Sinais , Fatores de Tempo
15.
PLoS One ; 15(4): e0231194, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271817

RESUMO

Various injuries to the neural tissues can cause irreversible damage to multiple functions of the nervous system ranging from motor control to cognitive function. The limited treatment options available for patients have led to extensive interest in studying the mechanisms of neuronal regeneration and recovery from injury. Since many neurons are terminally differentiated, by increasing cell survival following injury it may be possible to minimize the impact of these injuries and provide translational potential for treatment of neuronal diseases. While several cell types are known to survive injury through plasma membrane repair mechanisms, there has been little investigation of membrane repair in neurons and even fewer efforts to target membrane repair as a therapy in neurons. Studies from our laboratory group and others demonstrated that mitsugumin 53 (MG53), a muscle-enriched tripartite motif (TRIM) family protein also known as TRIM72, is an essential component of the cell membrane repair machinery in skeletal muscle. Interestingly, recombinant human MG53 (rhMG53) can be applied exogenously to increase membrane repair capacity both in vitro and in vivo. Increasing the membrane repair capacity of neurons could potentially minimize the death of these cells and affect the progression of various neuronal diseases. In this study we assess the therapeutic potential of rhMG53 to increase membrane repair in cultured neurons and in an in vivo mouse model of neurotrauma. We found that a robust repair response exists in various neuronal cells and that rhMG53 can increase neuronal membrane repair both in vitro and in vivo. These findings provide direct evidence of conserved membrane repair responses in neurons and that these repair mechanisms can be targeted as a potential therapeutic approach for neuronal injury.


Assuntos
Regeneração Nervosa , Nervo Isquiático/lesões , Nervo Isquiático/fisiopatologia , Cicatrização , Animais , Linhagem Celular , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Lesões por Esmagamento/patologia , Lesões por Esmagamento/fisiopatologia , Modelos Animais de Doenças , Humanos , Proteínas de Membrana/metabolismo , Membranas , Camundongos Endogâmicos C57BL , Regeneração Nervosa/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Proteínas Recombinantes/farmacologia , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Proteínas com Motivo Tripartido/farmacologia , Cicatrização/efeitos dos fármacos
16.
Wei Sheng Yan Jiu ; 49(1): 14-18, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-32290908

RESUMO

OBJECTIVE: To investigate the expression of S100ß protein and mRNA of Schwann cells(SC) in sciatic nerves of 2, 5-hexanedione(HD) intoxicated rats. METHODS: Nine-week old SPF male Wistar rats were administered at daily dosing of 100 and 300 mg/kg by intraperitoneal injection for continuous 8 weeks(five times every week). Age-matched control rats received an equivalent volume of normal saline. Ten rats in each group were sacrificed and sciatic nerves were excised for S100ß determination, with excised sciatic nerves from another three rats for morphological observation through electron microscope. At the end of the exposure, the other 8-week treated animals were allowed to naturally recover for 8 weeks and sciatic nerves were excised at the end of the test. S100ß protein contents were determined by immunohistochemistry method, and mRNA expression was observed by real-time quantitative polymerase chain reaction(PCR). RESULTS: HD intoxication with 300 mg/kg was associated with severe neurological deficits of paralysis in hindlimbs, accompanied with evident movement gait abnormalities for 100 mg/kg dosage. The morphological abnormalities in myelin sheath of sciatic nerves were observed through electron microscope after HD-exposure. The S100ß contents in 100 mg/kg and 300 mg/kg groups remained relatively unaffected with 92% and 79% of the control respectively after HD-intoxication, and a increase to 149%(P<0. 05) and 119% after a recovery of 8 weeks was accompanied with. As to S100ß mRNA, HD-intoxication was associated with decreased expression to 0. 65(P<0. 05) and 0. 56 times(P<0. 05) of the control, and 1. 46 and 0. 87 times for 8-week recovery individually. CONCLUSION: The S100ß protein and mRNA levels were influenced by HD exposure, and the result suggested that S100ß might be involved in HD-induced peripheral axonopathy.


Assuntos
Hexanonas/toxicidade , Subunidade beta da Proteína Ligante de Cálcio S100/metabolismo , Células de Schwann/efeitos dos fármacos , Nervo Isquiático/efeitos dos fármacos , Animais , Masculino , Ratos , Ratos Wistar , Células de Schwann/metabolismo , Nervo Isquiático/patologia , Testes de Toxicidade
17.
Acta Neuropathol Commun ; 8(1): 32, 2020 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-32169121

RESUMO

Charcot-Marie-Tooth disease (CMT) is a group of inherited neurological disorders of the peripheral nervous system. CMT is subdivided into two main types: a demyelinating form, known as CMT1, and an axonal form, known as CMT2. Nearly 30 genes have been identified as a cause of CMT2. One of these is the 'dehydrogenase E1 and transketolase domain containing 1' (DHTKD1) gene. We previously demonstrated that a nonsense mutation [c.1455 T > G (p.Y485*)] in exon 8 of DHTKD1 is one of the disease-causing mutations in CMT2Q (MIM 615025). The aim of the current study was to investigate whether human disease-causing mutations in the Dhtkd1 gene cause CMT2Q phenotypes in a mouse model in order to investigate the physiological function and pathogenic mechanisms associated with mutations in the Dhtkd1 gene in vivo. Therefore, we generated a knock-in mouse model with the Dhtkd1Y486* point mutation. We observed that the Dhtkd1 expression level in sciatic nerve of knock-in mice was significantly lower than in wild-type mice. Moreover, a histopathological phenotype was observed, reminiscent of a peripheral neuropathy, including reduced large axon diameter and abnormal myelination in peripheral nerves. The knock-in mice also displayed clear sensory defects, while no abnormalities in the motor performance were observed. In addition, accumulation of mitochondria and an elevated energy metabolic state was observed in the knock-in mice. Taken together, our study indicates that the Dhtkd1Y486* knock-in mice partially recapitulate the clinical phenotypes of CMT2Q patients and we hypothesize that there might be a compensatory effect from the elevated metabolic state in the knock-in mice that enables them to maintain their normal locomotor function.


Assuntos
Doença de Charcot-Marie-Tooth/genética , Modelos Animais de Doenças , Camundongos , Mitocôndrias/patologia , Nervo Isquiático/metabolismo , Distúrbios Somatossensoriais/genética , Animais , Axônios/patologia , Axônios/ultraestrutura , Doença de Charcot-Marie-Tooth/patologia , Doença de Charcot-Marie-Tooth/fisiopatologia , Códon sem Sentido , Metabolismo Energético , Técnicas de Introdução de Genes , Cetona Oxirredutases/genética , Cetona Oxirredutases/metabolismo , Camundongos Transgênicos , Microscopia Eletrônica de Transmissão , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Mitocôndrias Musculares/metabolismo , Mitocôndrias Musculares/patologia , Mitocôndrias Musculares/ultraestrutura , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Músculo Esquelético/ultraestrutura , Bainha de Mielina/patologia , Bainha de Mielina/ultraestrutura , Condução Nervosa , Degradação do RNAm Mediada por Códon sem Sentido/genética , Nervos Periféricos/patologia , Nervos Periféricos/ultraestrutura , Fenótipo , Mutação Puntual , Nervo Isquiático/patologia , Nervo Isquiático/ultraestrutura , Distúrbios Somatossensoriais/patologia , Distúrbios Somatossensoriais/fisiopatologia
18.
ACS Appl Mater Interfaces ; 12(14): 16168-16177, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32182427

RESUMO

Peripheral nerve injury (PNI) was the leading cause of permanent dysfunction in movement and sensation. Synthesized nerve guide conduits (NGCs) with Schwann Cells (SCs) can help peripheral nerve regeneration. However, poor accessibility of SCs and lack of full coverage of seeded cells on NGCs can lead to failure of nerve regeneration across long gaps and full functional recovery. To overcome these limitations, bone marrow stromal cells (BMSCs) and a novel culture method were proposed in the current study. BMSCs were harvested and seeded on a never growth factor (NGF)-loaded PCL nanofibrous NGCs and cultured with a rotary cell culture system (RCCS) before implantation. The NGCs were tested in vitro with PC-12 cells to validate the bioactivity of released NGF and to access its ability to promote neurite extension. Also, the NGCs were tested in vivo with rat sciatic nerve model to exam its potential in bridging the long gap (15 mm segmental defect). The efficacy of the NGCs was investigated based on the results of the functional test, electrophysiology test, muscle atrophy, and histological analysis. The results of in vitro PC-12 cell study confirmed the bioactivity of released NGF and showed a significant increase in the neurite extension with the help of PEG-diamine and BSA. These results showed that the novel loading method could preserve the bioactivity of growth factors and achieve a sustained release in vitro. Besides, the results of the in vivo study exhibited a significant increase with the combination of all additives. These results showed that with the help of NGF and RCCS, the NGCs with the seeded BMSCs could enhance peripheral nerve regeneration across long nerve injury gaps.


Assuntos
Nanofibras/química , Regeneração Nervosa/efeitos dos fármacos , Traumatismos dos Nervos Periféricos/terapia , Nervo Isquiático/efeitos dos fármacos , Animais , Reatores Biológicos , Técnicas de Cultura de Células , Modelos Animais de Doenças , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Nanofibras/uso terapêutico , Fatores de Crescimento Neural/química , Fatores de Crescimento Neural/metabolismo , Células PC12 , Traumatismos dos Nervos Periféricos/patologia , Nervos Periféricos/efeitos dos fármacos , Nervos Periféricos/crescimento & desenvolvimento , Nervos Periféricos/patologia , Ratos , Células de Schwann/efeitos dos fármacos , Nervo Isquiático/crescimento & desenvolvimento , Nervo Isquiático/patologia
19.
Oxid Med Cell Longev ; 2020: 6431459, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32184918

RESUMO

Oxidative stress has been recognized as the contributor to diabetic peripheral neuropathy (DPN). Antioxidant strategies have been most widely explored; nevertheless, whether antioxidants alone prevent DPN still remains inconclusive. In the present study, we established an in vitro DPN cell model for drug screening using Schwann RSC96 cells under high glucose (HG) stimulation, and we found that salvianolic acid A (SalA) mitigated HG-induced injury evidenced by cell viability and myelination. Mechanistically, SalA exhibited strong antioxidative effects by inhibiting 1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing reactive oxygen species (ROS), malondialdehyde (MDA), and oxidized glutathione (GSSG) content, as well as upregulating antioxidative enzyme mRNA expression. In addition, SalA significantly extenuated neuroinflammation with downregulated inflammatory factor mRNA expression. Furthermore, SalA improved the mitochondrial function of HG-injured Schwann cells by scavenging mitochondrial ROS, decreasing mitochondrial membrane potential (MMP), and enhancing ATP production, as well as upregulating oxidative phosphorylation gene expression. More importantly, we identified nuclear factor-E2-related factor 2 (Nrf2) as the upstream regulator which mediated protective effects of SalA on DPN. SalA directly bound to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) and thus disrupted the interaction of Nrf2 and Keap1 predicted by LibDock of Discovery Studio. Additionally, SalA significantly inhibited Nrf2 promoter activity and downregulated Nrf2 mRNA expression but without affecting Nrf2 protein expression. Interestingly, SalA upregulated the nuclear Nrf2 expression and promoted Nrf2 nuclear translocation by high content screening assay, which was confirmed to be involved in its antiglucotoxicity effect by the knockdown of Nrf2 in RSC96 cells. In KK-Ay mice, we demonstrated that SalA could effectively improve the abnormal glucose and lipid metabolism and significantly protect against DPN by increasing the mechanical withdrawal threshold and sciatic nerve conduction velocity and restoring the ultrastructural impairment of the injured sciatic nerve induced by diabetes. Hence, SalA protected against DPN by antioxidative stress, attenuating neuroinflammation, and improving mitochondrial function via Nrf2. SalA may be prospective therapeutics for treating DPN.


Assuntos
Ácidos Cafeicos/uso terapêutico , Neuropatias Diabéticas/tratamento farmacológico , Neuropatias Diabéticas/metabolismo , Lactatos/uso terapêutico , Fator 2 Relacionado a NF-E2/metabolismo , Fármacos Neuroprotetores/uso terapêutico , Doenças do Sistema Nervoso Periférico/tratamento farmacológico , Doenças do Sistema Nervoso Periférico/metabolismo , Animais , Ácidos Cafeicos/química , Ácidos Cafeicos/farmacologia , Linhagem Celular , Neuropatias Diabéticas/patologia , Glucose/toxicidade , Inflamação/patologia , Lactatos/química , Lactatos/farmacologia , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Doenças do Sistema Nervoso Periférico/patologia , Ratos , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Nervo Isquiático/ultraestrutura
20.
J Nanobiotechnology ; 18(1): 46, 2020 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-32169062

RESUMO

BACKGROUND: Peripheral nerve injury is one common clinical disease worldwide, in which sciatic nerve is anatomically the most challenging to regenerate given its length and large cross-sectional area. For the present, autologous nerve grafting remains to be the most ideal strategy when treating with sciatic nerve injury. However, this method sacrifices healthy nerves and requires highly intensive surgery, still calling for other advanced alternatives for nerve grafting. RESULTS: In this study, we utilized previously well-established gene delivery system to dually deliver plasmid DNA (pDNA) encoding vascular endothelial growth factor (VEGF) and nerve growth factor (NGF), exploring therapeutics for sciatic nerve injury. Low-molecular-weight branched polyethylenimine (bPEI) was constructed as the backbone structure of gene vectors, and it was further crosslinked to synthesize degradable polycations via the conjugation of dialdehydes. Potential synergistic effect between VEGF and NGF proteins were observed on rat sciatic nerve crush injury model in this study. CONCLUSIONS: We concluded that dual delivery of plasmid VEGF and NGF as gene therapy could enhance sciatic nerve regeneration.


Assuntos
Fator de Crescimento Neural/genética , Fator de Crescimento Neural/metabolismo , Regeneração Nervosa/fisiologia , Nervo Isquiático/crescimento & desenvolvimento , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Anoplura/química , Autoenxertos , Modelos Animais de Doenças , Técnicas de Transferência de Genes , Terapia Genética/métodos , Vetores Genéticos , Nanopartículas/química , Tamanho da Partícula , Polietilenoimina , Piridinas , Ratos , Nervo Isquiático/lesões , Nervo Isquiático/patologia , Neuropatia Ciática
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