Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 3.606
Filtrar
1.
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
2.
Scand J Immunol ; 92(2): e12896, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32557749

RESUMO

Sciatic nerve injury affects quality of life. Many immune cells and inflammatory cytokines have been reported to be involved in sciatic nerve injury, but little is known about the ligands and receptors that trigger inflammatory responses. By using a modified sciatic nerve clamp injury method, we found that the recruitment of Schwann cells and the inflammatory response were enhanced after sciatic nerve injury. Toll-like receptor 4 (TLR4), one of the major members of the TLR family, is highly expressed in Schwann cells. Under certain conditions, myeloid differentiation protein 2 (MD2) binds to TLR4 on the membrane and plays important roles in the inflammatory response. The reductions in the recruitment of Schwann cells and the inflammatory response induced by the blockade of TLR4 or MD2 suggest that TLR4 and MD2 are involved in sciatic nerve injury. What are the endogenous signals that activate the inflammatory response? A large number of free saturated fatty acids (SFAs) are released from Schwann cells, adipocytes and the blood after sciatic nerve injury. Liang et al reported that Schwann cells can be stimulated by palmitic acid (PA). Here, we found that the expression and secretion of TNF-α and IL-6 were enhanced by PA treatment. Moreover, PA activated TLR4 signalling pathway-related proteins and stimulated a strong association between TLR4 and MD2. Blocking TLR4 or MD2 reversed the PA-induced inflammatory response and TLR4 downstream signalling pathway. Thus, we speculated that SFAs act as endogenous ligands that activate TLR4/MD2, thus triggering Schwann cell inflammation during sciatic nerve injury.


Assuntos
Ácidos Graxos/farmacologia , Inflamação/metabolismo , Células de Schwann/efeitos dos fármacos , Nervo Isquiático/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Ácidos Graxos/metabolismo , Masculino , Compressão Nervosa , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões
3.
Acta Orthop Traumatol Turc ; 54(3): 330-336, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32544069

RESUMO

OBJECTIVE: The aim of this study was to compare the outcomes of primary nerve repair using either ethyl-cyanoacrylate or conventional microsuture technique in a rat peripheral nerve injury model. METHODS: In this study, a total of 30 Wistar Albino rats weighing between 220 and 275 g were used. The rats were randomly divided into three groups (10 in each), including one control (group 1) and two experimental groups (group 2, conventional microsuture repair; group 3, cyanoacrylate repair). In each group, the sciatic nerve was identified and transected. No further intervention was performed in group 1. The nerve was repaired using the epineural technique with a 10/0 atraumatic nylon in group 2 and synthetic cyanoacrylate adhesive in group 3. At the fifth postoperative week, needle electromyography (EMG) was performed to measure distal latency, combined muscle action potential (CMAP), and motor nerve conduction velocity (MNCV). Following the EMG recordings, animals were euthanized. Nerve samples were collected to evaluate vacuolar degeneration, fibrosis, and foreign body reaction histopathologically. RESULTS: In the EMG analysis, mean distal latency was significantly shorter in group 1 (0.85±0.09 ms) than in groups 2 (1.17±0.25 ms) (p=0.0052) and 3 (1.14±0.14 ms) (p=0.0026) while no significant differences existed between groups 2 and 3 (p>0.9999). The mean CMAP was greater in group 1 (10.5±0.35 mV) than in groups 2 (2.86±1.28 mV) (p=0.011) and 3 (2.16±1.34 mV) (p=0.0002), but there was no significant difference between groups 2 and 3 (p>0.9999). The mean MNCV was 53.5±5.95, 39.62±7.31, and 39.84±4.73 mm/sec in groups 1, 2, and 3, respectively. There was a significant difference between groups 1 and 2 (p=0.0052) and between 1 and 3 (p=0.0026), but not between 2 and 3 (p>0.9999). In the histopathological evaluation, the mean vacuolar degeneration score was 0, 2.12, and 1.88 in groups 1, 2, and 3, respectively. No obvious difference was observed between groups 2 and 3 (p=0.743). The mean fibrosis score was 0, 1.62, and 1.77 in groups 1, 2, and 3, respectively. There was no significant difference between groups 2 and 3 (p=0.888). The mean foreign body reaction score was 0, 2.5, and 2.44 in groups 1, 2, and 3, respectively. No difference was present between groups 2 and 3 (p=0.743). CONCLUSION: Primary nerve repair using the cyanoacrylate adhesive may provide similar electrophysiological and histopathological results as compared to the conventional microsuture repair.


Assuntos
Cianoacrilatos/farmacologia , Procedimentos Neurocirúrgicos/métodos , Traumatismos dos Nervos Periféricos/cirurgia , Nervo Isquiático , Procedimentos Cirúrgicos sem Sutura/métodos , Animais , Eletromiografia/métodos , Masculino , Regeneração Nervosa , Traumatismos dos Nervos Periféricos/diagnóstico , Ratos , Ratos Wistar , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Técnicas de Sutura , Adesivos Teciduais/farmacologia , Resultado do Tratamento
5.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 42(2): 190-196, 2020 Apr 28.
Artigo em Chinês | MEDLINE | ID: mdl-32385024

RESUMO

Objective To explore the value of conventional ultrasound combined with shear-wave elastography in the quantitative evaluation of sciatic nerve crush injury in rabbit models. Methods Forty healthy male New Zealand white rabbits were randomly divided into four groups (n=10 in each group):three crush injury (CI) groups (2,4,and 8 weeks after crush) and control group (without injury). The thickness and stiffness of the crushed sciatic nerves and denervated triceps surae muscles were measured at different time points and compared with histopathologic parameters. Inter-reader variability was assessed with intraclass correlation coefficients. Results Compared with the control group,the inner diameters of the sciatic nerves significantly increased in the 2-week CI group [(1.65±0.34) mm vs. (0.97±0.15) mm,P=0.00] but recovered to the nearly normal level in the 8-week CI group [(1.12±0.18) mm vs. (0.97±0.15) mm,P=0.06];however,compared with control group [(8.75±1.02)kPa],the elastic modulus of the nerves increased significantly in all the CI groups [2-week:(14.77±2.53) kPa;4-week:(19.12±3.46) kPa;and 8-week:(28.39±5.26) kPa;all P=0.00];pathologically,massive hyperplasia of collagen fibers were found in the nerve tissues. The thickness of denervated triceps surae muscle decreased gradually,and the elastic modulus decreased 2 weeks after injury but increased gradually in the following 6 weeks;pathologically,massive hyperplasia of collagen fibers and adipocytes infiltration were visible,along with decreased muscle wet-weight ratio and muscle fiber cross-sectional area. The inter-reader agreements were good. Conclusion Conventional ultrasound combined with shear-wave elastography is feasible for the quantitative evaluation of the morphological and mechanical properties of crushed nerves and denervated muscles.


Assuntos
Lesões por Esmagamento/diagnóstico por imagem , Técnicas de Imagem por Elasticidade , Nervo Isquiático/lesões , Ultrassonografia , Animais , Módulo de Elasticidade , Masculino , Músculo Esquelético/inervação , Músculo Esquelético/patologia , Coelhos , Distribuição Aleatória
6.
Ulus Travma Acil Cerrahi Derg ; 26(3): 361-365, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32436974

RESUMO

BACKGROUND: The debate continues concerning surgical timing in a peripheral nerve injury. This study aims to evaluate the result of immediate versus delayed primary (after seven days) repair of peripheral nerve injury. METHODS: In this study, Wistar rats were divided into four groups as follows: The nerve was sharply transected in Group 1, 2 and 4. It was immediately sutured in Group 1 and sutured seven days later in Group 2, and it was not sutured in Group 4. In Group 3, the left sciatic nerve was only explored. Eight weeks later, tissue samples were extracted from the injured nerve area. Both gastrocnemius muscles were weighed. The nerve samples were examined for axon degeneration. Myelin vacuolization, axon irregularity, and edema/inflammation parameters were evaluated. RESULTS: There were not any significant differences in the score of axon degeneration and the weight of the gastrocnemius muscle between the immediate and delayed primary repair groups. However, these parameters were significantly better in both repair groups than to be in the control group and significantly worse than to be in the sham-operated group. CONCLUSION: To delay the repair about one week did not affect the histological results and weight of the muscle that was innervated by the sectioned nerve comparing to be in the immediate repair in a sciatic nerve transaction model in rats.


Assuntos
Procedimentos Neurocirúrgicos , Traumatismos dos Nervos Periféricos/cirurgia , Nervo Isquiático , Animais , Modelos Animais de Doenças , Ratos , Ratos Wistar , Nervo Isquiático/lesões , Nervo Isquiático/cirurgia , Tempo para o Tratamento
7.
Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi ; 36(2): 111-116, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32314707

RESUMO

Objective To investigate the expression and distribution of spalt-like transcription factor 1 (Sall1) in the lumbar spinal dorsal horn of mice with sciatic nerve branch selective injury. Methods BALB/c mice aged 6~8 weeks old were randomly divided into a control group, a sham operation group and a sciatic nerve branch selective injury group. The mechanical withdrawal threshold (MWT) was measured on the 1st day before the establishment of the model and on the 3rd, 7th, 10th and 14th day after operation. On the 3rd, 7th, 10th and 14th day after operation, the dorsal horn was collected from the L4-6 segments of the affected spinal cord. The expression of Sall1 and the mRNA levels of inflammatory cytokines such as interleukin 1ß (IL-1ß), IL-6 and tumor necrosis factor alpha (TNF-α) on the 7th day after operation were detected by real-time quantitative PCR. The expression of Sall1 protein was determined by Western blot analysis at the above four time points. Immunohistochemical staining and semi-quantitative analysis were performed to analyze the expression and distribution of Sall1 in the spinal cord on the 3rd, 7th, 10th and 14th day after operation. Results Compared with the control group and the sham operation group, MWT of the SNI group decreased on the 3rd, 7th, 10th and 14th day after operation. Compared with the control group, the mRNA and protein levels of Sall1 in SNI group decreased on the 7th, 10th and 14th day after operation. The mRNA levels of IL-1ß, IL-6 and TNF-α increased at 7th day after operation. Sall1 in the control group and SNI group was mainly distributed in the spinal dorsal horn, and the expression in the SNI group was significantly lower than that in the control group at all time points except for the 3th day after operation. Conclusion Sall1 is distributed in the dorsal horn of spinal cord. Sciatic nerve branch selective injury could decrease the expression of Sall1 and increase the expression of IL-1ß, IL-6 and TNF-α mRNA in the dorsal horn of lumbar spinal cord.


Assuntos
Nervo Isquiático/lesões , Corno Dorsal da Medula Espinal/metabolismo , Fatores de Transcrição/metabolismo , Animais , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Aleatória , Fator de Necrose Tumoral alfa/metabolismo
8.
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
9.
Braz J Med Biol Res ; 53(5): e9255, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32348427

RESUMO

The neurochemical mechanisms underlying neuropathic pain (NP) are related to peripheral and central sensitization caused by the release of inflammatory mediators in the peripheral damaged tissue and ectopic discharges from the injured nerve, leading to a hyperexcitable state of spinal dorsal horn neurons. The aim of this work was to clarify the role played by cyclooxygenase (COX) in the lesioned peripheral nerve in the development and maintenance of NP by evaluating at which moment the non-steroidal anti-inflammatory drug indomethacin, a non-selective COX inhibitor, attenuated mechanical allodynia after placing one loose ligature around the nervus ischiadicus, an adaptation of Bennett and Xie's model in rodents. NP was induced in male Wistar rats by subjecting them to chronic constriction injury (CCI) of the nervus ischiadicus, placing one loose ligature around the peripheral nerve, and a sham surgery (without CCI) was used as control. Indomethacin (2 mg/kg) or vehicle was intraperitoneally and acutely administered in each group of rats and at different time windows (1, 2, 4, 7, 14, 21, and 28 days) after the CCI or sham surgical procedures, followed by von Frey's test for 30 min. The data showed that indomethacin decreased the mechanical allodynia threshold of rats on the first, second, and fourth days after CCI (P<0.05). These findings suggested that inflammatory mechanisms are involved in the induction of NP and that COX-1 and COX-2 are involved in the induction but not in the maintenance of NP.


Assuntos
Indometacina/administração & dosagem , Neuralgia/tratamento farmacológico , Medição da Dor , Nervo Isquiático/lesões , Animais , Constrição , Modelos Animais de Doenças , Masculino , Neuralgia/etiologia , Limiar da Dor , Ratos , Ratos Sprague-Dawley , Ratos Wistar
10.
Mol Immunol ; 121: 81-91, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32172028

RESUMO

Traumatic injury to the peripheral nervous system (PNS) is the most common cause of acquired nerve damage and impairs the quality of life of patients. The success of nerve regeneration depends on distal stump degeneration, tissue clearance and remodeling, processes in which the immune system participates. We previously reported improved motor recovery in sciatic nerve crush mice following adoptive transfer of lymphocytes, which migrated to the lesion site. However, lymphocyte activity and the nerve tissue response remain unexplored. Thus, in the present study, we evaluated sciatic nerve regeneration and T cell polarization in lymphocyte recipient mice. Splenic lymphocytes were isolated from mice 14 days after sciatic nerve crush and transferred to axotomized animals three days postinjury. Immediate lymphocyte migration to the crushed nerve was confirmed by in vivo imaging. Phenotyping of T helper (Th) cells by flow cytometry revealed an increased frequency of the proinflammatory Th1 and Th17 cell subsets in recipient mice at 7 days and showed that the frequency of these cells remained unchanged for up to 21 days. Moreover, nerve regeneration was improved upon cell therapy, as shown by sustained immunolabeling of axons, Schwann cells, growth-associated protein 43 and BDNF from 14 to 28 days after lesion. Macrophage and IgG immunolabeling were also higher in cell-transferred mice at 14 and 21 days following nerve crush. Functionally, we observed better sensory recovery in the lymphocyte-treated group. Overall, our data demonstrate that enhanced inflammation early after nerve injury has beneficial effects for the regenerative process, improving tissue clearance and axonal regrowth towards the target organs.


Assuntos
Transferência Adotiva/métodos , Transfusão de Linfócitos , Regeneração Nervosa/imunologia , Traumatismos dos Nervos Periféricos/terapia , Nervo Isquiático/lesões , Animais , Axônios/fisiologia , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Compressão Nervosa/efeitos adversos , Traumatismos dos Nervos Periféricos/imunologia , Traumatismos dos Nervos Periféricos/patologia , Qualidade de Vida , Nervo Isquiático/citologia , Nervo Isquiático/fisiologia , Baço/citologia
11.
Plast Reconstr Surg ; 145(4): 949-956, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32221212

RESUMO

BACKGROUND: Nerve regeneration after an injury should occur in a timely fashion for function to be restored. Current methods cannot monitor regeneration prior to muscle reinnervation. Diffusion tensor imaging has been previously shown to provide quantitative indices after nerve recovery. The goal of this study was to validate the use of this technology following nerve injury via a series of rat sciatic nerve injury/repair studies. METHODS: Sprague-Dawley rats were prospectively divided by procedure (sham, crush, or cut/repair) and time points (1, 2, 4, and 12 weeks after surgery). At the appropriate time point, each animal was euthanized and the sciatic nerve was harvested and fixed. Data were obtained using a 7-Tesla magnetic resonance imaging system. For validation, findings were compared to behavioral testing (foot fault asymmetry and sciatic function index) and cross-sectional axonal counting of toluidine blue-stained sections examined under light microscopy. RESULTS: Sixty-three rats were divided into three treatment groups (sham, n = 21; crush, n = 23; and cut/repair, n = 19). Fractional anisotropy was able to differentiate between recovery following sham, crush, and cut/repair injuries as early as 2 weeks (p < 0.05), with more accurate differentiation thereafter. More importantly, the difference in anisotropy between distal and proximal regions recognized animals with successful and failed recoveries according to behavioral analysis, especially at 12 weeks. In addition, diffusion tension imaging-based tractography provided a visual representation of nerve continuity in all treatment groups. CONCLUSIONS: Diffuse tensor imaging is an objective and noninvasive tool for monitoring nerve regeneration. Its use could facilitate earlier detection of failed repairs to potentially help improve outcomes.


Assuntos
Imagem de Tensor de Difusão/métodos , Nervo Isquiático/lesões , Animais , Lesões por Esmagamento/fisiopatologia , Lesões por Esmagamento/cirurgia , Modelos Animais de Doenças , Masculino , Regeneração Nervosa/fisiologia , Ratos Sprague-Dawley , Recuperação de Função Fisiológica/fisiologia , Nervo Isquiático/fisiologia , Nervo Isquiático/cirurgia
12.
J Vis Exp ; (156)2020 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-32116292

RESUMO

Compared to the Sciatic Functional Index (SFI), kinematic analysis is a more reliable and sensitive method for performing functional evaluations of sciatic nerve injury rodent models. In this protocol, we describe a novel kinematic analysis method that uses a three-dimensional (3D) motion capture apparatus for functional evaluations using a rat sciatic nerve crush injury model. First, the rat is familiarized with treadmill walking. Markers are then attached to the designated bone landmarks and the rat is made to walk on the treadmill at the desired speed. Meanwhile, the posterior limb movements of the rat are recorded using four cameras. Depending on the software used, marker tracings are created using both automatic and manual modes and the desired data are produced after subtle adjustments. This method of kinematic analysis, which uses a 3D motion capture apparatus, offers numerous advantages, including superior precision and accuracy. Many more parameters can be investigated during the comprehensive functional evaluations. This method has several shortcomings that require consideration: The system is expensive, can be complicated to operate, and may produce data deviations due to skin shifting. Nevertheless, kinematic analysis using a 3D motion capture apparatus is useful for performing functional anterior and posterior limb evaluations. In the future, this method may become increasingly useful for generating accurate assessments of various traumas and diseases.


Assuntos
Lesões por Esmagamento/fisiopatologia , Nervo Isquiático/lesões , Neuropatia Ciática/fisiopatologia , Animais , Fenômenos Biomecânicos , Masculino , Ratos Endogâmicos Lew , Nervo Isquiático/fisiologia , Caminhada/fisiologia
13.
J Surg Res ; 251: 311-320, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32200322

RESUMO

BACKGROUND: Outcome assessments that evaluate post-transection nerve repair do not often correlate with one another. The aims of this study were twofold: to compare four nerve repair techniques with each other and incorporate both negative and positive control groups and to identify possible correlations between outcome assessments. MATERIALS AND METHODS: Sciatic nerve transection and repair was performed in Lewis rats using one of the following techniques: interrupted epineural, running epineural, grouped fascicular, epineural with absorbable type I collagen wrap, and high tension for incorporation of a negative control. A sham surgery group was also included as a positive control group. Outcomes were compared using assessments of functional recovery (behavior and electrophysiology) and nerve regrowth (imaging and histomorphometry). Three-dimensional printed custom electrode stabilization and imaging devices were designed and fabricated to provide standardization in assessment between subjects. RESULTS: Nerve repair was performed in 48 male Lewis rats. In all animals, functional testing was performed at week 13. The sham group (n = 7) performed the best on both behavioral assays (P < 0.001) and electrophysiology assessments (P < 0.001). The negative control group (high tension) performed poorest on multiple assessments, and there were no significant differences observed for any of the four repair types. Positive correlations were observed between behavioral and histomorphometric tests. CONCLUSIONS: There was no difference in outcome between the four types of nerve repair. High-tension nerve repair represents an ideal negative control. Not all assessment methods correlate equally, and consistent use of complimentary outcome assessments could allow for improved comparison between studies.


Assuntos
Regeneração Nervosa , Procedimentos Neurocirúrgicos/métodos , Nervo Isquiático/lesões , Animais , Masculino , Procedimentos Neurocirúrgicos/reabilitação , Ratos Endogâmicos Lew , Teste de Desempenho do Rota-Rod , Nervo Isquiático/fisiologia
14.
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
15.
Pain Pract ; 20(5): 510-521, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32124540

RESUMO

OBJECTIVES: To assess the supraspinal working mechanisms of the burst spinal cord stimulation (SCS) mode, we used functional magnetic resonance imaging (fMRI) in chronic neuropathic rats. We hypothesized that active recharge burst SCS would induce a more profound blood oxygenation level-dependent (BOLD) signal increase in areas associated with cognitive-emotional aspects of pain, as compared to tonic SCS. METHODS: Sprague Dawley rats (n = 17) underwent a unilateral partial sciatic nerve ligation, which resulted in chronic neuropathic pain. Quadripolar SCS electrodes were epidurally positioned on top of the dorsal columns at Th13. Isoflurane-anesthetized (1.5%) rats received either tonic SCS (n = 8) or burst SCS (n = 9) at 66% of motor threshold. BOLD fMRI was conducted before, during, and after SCS using a 9.4-T horizontal bore scanner. RESULTS: Overall, both tonic and burst SCS induced a significant increase of BOLD signal levels in areas associated with the location and intensity of pain, and areas associated with cognitive-emotional aspects of pain. Additionally, burst SCS significantly increased BOLD signal levels in the raphe nuclei, nucleus accumbens, and caudate putamen. Tonic SCS did not induce a significant increase in BOLD signal levels in these areas. CONCLUSIONS: In conclusion, active recharge burst and tonic SCS have different effects on the intensity and localization of SCS-induced activation responses in the brain. This work demonstrates that active recharge burst is another waveform that can engage brain areas associated with cognitive-emotional aspects of pain as well as areas associated with location and intensity of pain. Previous studies showing similar engagement used only passive recharge burst.


Assuntos
Encéfalo/fisiopatologia , Neuralgia/fisiopatologia , Estimulação da Medula Espinal/métodos , Animais , Imagem por Ressonância Magnética , Masculino , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Medula Espinal/fisiopatologia
16.
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
17.
PLoS One ; 15(2): e0226289, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32015563

RESUMO

Calcium binding proteins are expressed throughout the central and peripheral nervous system and disruption of their activity has major consequences in a wide array of cellular processes, including transmission of nociceptive signals that are processed at the level of the spinal cord. We previously reported that the calcium binding protein, hippocalcin-like 4 (Hpcal4), is heavily expressed in interneurons of the superficial dorsal horn, and that its expression is significantly downregulated in a TR4 mutant mouse model that exhibits major pain and itch deficits due to loss of a subpopulation of excitatory interneurons. That finding suggested that Hpcal4 may be a contributor to the behavioral phenotype of the TR4 mutant mouse. To address this question, here we investigated the behavioral consequences of global deletion of Hpcal4 in a battery of acute and persistent pain and itch tests. Unexpectedly, with the exception of a mild reduction in acute baseline thermal responses, Hpcal4-deficient mice exhibit no major deficits in pain or itch responses, under normal conditions or in the setting of tissue or nerve injury. Taken together, our results indicate that the neural calcium sensor Hpcal4 likely makes a limited contribution to pain and itch processing.


Assuntos
Neurocalcina/metabolismo , Dor/metabolismo , Prurido/metabolismo , Animais , Escala de Avaliação Comportamental , Comportamento Animal , Cloroquina/administração & dosagem , Cloroquina/farmacologia , Técnicas de Inativação de Genes , Histamina/administração & dosagem , Histamina/farmacologia , Temperatura Alta , Interneurônios/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurocalcina/genética , Prurido/induzido quimicamente , Nervo Isquiático/lesões , Corno Dorsal da Medula Espinal/metabolismo
18.
Sci Rep ; 10(1): 1908, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024865

RESUMO

Perturbations in skeletal muscle metabolism have been reported for a variety of neuromuscular diseases. However, the role of metabolism after constriction injury to a nerve and the associated muscle atrophy is unclear. We have analyzed rat tibialis anterior (TA) four weeks after unilateral constriction injury to the sciatic nerve (DMG) and in the contralateral control leg (CTRL) (n = 7) to investigate changes of the metabolome, immunohistochemistry and protein levels. Untargeted metabolomics identified 79 polar metabolites, 27 of which were significantly altered in DMG compared to CTRL. Glucose concentrations were increased 2.6-fold in DMG, while glucose 6-phosphate (G6-P) was unchanged. Intermediates of the polyol pathway were increased in DMG, particularly fructose (1.7-fold). GLUT4 localization was scattered as opposed to clearly at the sarcolemma. Despite the altered localization, we found GLUT4 protein levels to be increased 7.8-fold while GLUT1 was decreased 1.7-fold in nerve damaged TA. PFK1 and GS levels were both decreased 2.1-fold, indicating an inability of glycolysis and glycogen synthesis to process glucose at sufficient rates. In conclusion, chronic nerve constriction causes increased GLUT4 levels in conjunction with decreased glycolytic activity and glycogen storage in skeletal muscle, resulting in accumulation of intramuscular glucose and polyol pathway intermediates.


Assuntos
Transportador de Glucose Tipo 4/metabolismo , Glucose/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/patologia , Traumatismos dos Nervos Periféricos/complicações , Polímeros/metabolismo , Animais , Modelos Animais de Doenças , Transportador de Glucose Tipo 1/metabolismo , Glicogênio/biossíntese , Glicólise , Humanos , Masculino , Metabolômica , Músculo Esquelético/inervação , Atrofia Muscular/etiologia , Traumatismos dos Nervos Periféricos/patologia , Ratos , Nervo Isquiático/lesões
19.
Sci Rep ; 10(1): 1880, 2020 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024965

RESUMO

FRMD6, a member of the group of FERM-domain proteins, is involved both in communication between cells, interactions with extracellular matrix, cellular apoptotic and regenerative mechanisms. FRMD6 was first discovered in the rodent sciatic nerve, and in the present immunohistochemical study we investigated the distribution of FRMD6 in the dorsal root ganglia (DRGs), sciatic nerve and spinal cord following sciatic nerve injury. FRMD6-immunoreactivity was found in the cytoplasm, nucleus or both, and in a majority of DRG neurons. FRMD6-immunoreactivity co-existed with several well-known neuronal markers, including calcitonin gene-related peptide, isolectin B4 and neurofilament 200 in mouse DRGs. After peripheral nerve injury, the FRMD6 mRNA levels and the overall percentage of FRMD6-positive neuron profiles (NPs) were decreased in ipsilateral lumbar DRGs, the latter mainly affecting small size neurons with cytoplasmic localization. Conversely, the proportion of NPs with nuclear FRMD6-immunoreactivity was significantly increased. In the sciatic nerve, FRMD6-immunoreactivity was observed in non-neuronal cells and in axons, and accumulated proximally to a ligation of the nerve. In the spinal cord FRMD6-immunoreactivity was detected in neurons in both dorsal and ventral horns, and was upregulated in ipsilateral dorsal horn after peripheral nerve axotomy. Our results demonstrate that FRMD6 is strictly regulated by peripheral nerve injury at the spinal level.


Assuntos
Gânglios Espinais/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Traumatismos dos Nervos Periféricos/patologia , Medula Espinal/patologia , Animais , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Modelos Animais de Doenças , Gânglios Espinais/citologia , Células HEK293 , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Células NIH 3T3 , Neurônios , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Nervo Isquiático/lesões , Regulação para Cima
20.
Sci Rep ; 10(1): 1984, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-32029747

RESUMO

The extracellular matrix is known to modulate cell adhesion and migration during tissue regeneration. However, the molecular mechanisms that fine-tune cells to extra-cellular matrix dynamics during regeneration of the peripheral nervous system remain poorly understood. Using the RSC96 Schwann cell line, we show that Sox2 directly controls fibronectin fibrillogenesis in Schwann cells in culture, to provide a highly oriented fibronectin matrix, which supports their organization and directional migration. We demonstrate that Sox2 regulates Schwann cell behaviour through the upregulation of multiple extracellular matrix and migration genes as well as the formation of focal adhesions during cell movement. We find that mouse primary sensory neurons and human induced pluripotent stem cell-derived motoneurons require the Sox2-dependent fibronectin matrix in order to migrate along the oriented Schwann cells. Direct loss of fibronectin in Schwann cells impairs their directional migration affecting the alignment of the axons in vitro. Furthermore, we show that Sox2 and fibronectin are co-expressed in proregenerative Schwann cells in vivo in a time-dependent manner during sciatic nerve regeneration. Taken together, our results provide new insights into the mechanisms by which Schwann cells regulate their own extracellular microenvironment in a Sox2-dependent manner to ensure the proper migration of neurons.


Assuntos
Fibronectinas/metabolismo , Regeneração Nervosa , Neurônios/fisiologia , Traumatismos dos Nervos Periféricos/patologia , Fatores de Transcrição SOXB1/metabolismo , Células de Schwann/fisiologia , Animais , Adesão Celular/fisiologia , Comunicação Celular/fisiologia , Linhagem Celular , Movimento Celular/fisiologia , Células Cultivadas , Microambiente Celular/fisiologia , Modelos Animais de Doenças , Matriz Extracelular/metabolismo , Feminino , Adesões Focais/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas , Microscopia Intravital , Cultura Primária de Células , Ratos , Células de Schwann/citologia , Nervo Isquiático/lesões
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA