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The in vivo three-dimensional genomic architecture of adult mature neurons at homeostasis and after medically relevant perturbations such as axonal injury remains elusive. Here, we address this knowledge gap by mapping the three-dimensional chromatin architecture and gene expression program at homeostasis and after sciatic nerve injury in wild-type and cohesin-deficient mouse sensory dorsal root ganglia neurons via combinatorial Hi-C, promoter-capture Hi-C, CUT&Tag for H3K27ac and RNA-seq. We find that genes involved in axonal regeneration form long-range, complex chromatin loops, and that cohesin is required for the full induction of the regenerative transcriptional program. Importantly, loss of cohesin results in disruption of chromatin architecture and severely impaired nerve regeneration. Complex enhancer-promoter loops are also enriched in the human fetal cortical plate, where the axonal growth potential is highest, and are lost in mature adult neurons. Together, these data provide an original three-dimensional chromatin map of adult sensory neurons in vivo and demonstrate a role for cohesin-dependent long-range promoter interactions in nerve regeneration.
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Axones , Cromatina , Cohesinas , Regeneración Nerviosa , Regiones Promotoras Genéticas , Células Receptoras Sensoriales , Animales , Células Receptoras Sensoriales/metabolismo , Células Receptoras Sensoriales/fisiología , Ratones , Regiones Promotoras Genéticas/genética , Cromatina/metabolismo , Regeneración Nerviosa/genética , Regeneración Nerviosa/fisiología , Axones/metabolismo , Axones/fisiología , Humanos , Proteínas Cromosómicas no Histona/metabolismo , Proteínas Cromosómicas no Histona/genética , Elementos de Facilitación Genéticos/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Ganglios Espinales/metabolismo , Ganglios Espinales/citología , Nervio Ciático/metabolismoRESUMEN
Objective: To explore the potential evidence of active peripheral nerve necrosis when n-hexane produces toxic effects on peripheral nerves. Methods: In May 2023, 36 SPF grade SD male rats with a body weight of 200-220 g were divided into 4 groups with 9 rats in each group and given normal saline and different doses of n-hexane (168, 675, 2 700 mg/kg) by gavage for 6 consecutive weeks (5 days/week). Three rats in each group were killed at the 2nd, 4th and 6th week, respectively. The spinal cord to sciatic nerve tissue was broken and the supernatant was extracted for SDS-PAGE protein isolation. The expression level of Sarm1 protein was analyzed with the ß-Actin color strip of internal reference protein by Western blot. The expression of Sarm1 protein was analyzed by the gray ratio of the two. At the 6th week, the sciatic nerve sections of the each group were observed by light microscope and electron microscope. Results: The number of axons was obviously reduced by light microscopy. According to electron microscope, myelin lesions were mainly local disintegration, deformation, and different thickness. The deformation of axonal surface became smaller. The axons in the nerve bundle membrane showed degeneration and reduction. The gray ratio of Sarm1 protein and internal reference protein bands in each group had no significant change at the second week of exposure, and the ratio of SARM1 protein to internal reference protein bands was 1.47 in the high dose group at the fourth week, and 1.51 and 1.89 in the middle and high dose group at the sixth week, respectively. Conclusion: Waller's degeneration was observed in sciatic neuropathologic manifestations of n-hexane-poisoned rats, and the expression level of Sarm1 protein increased.
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Hexanos , Nervio Ciático , Animales , Masculino , Ratas , Proteínas del Dominio Armadillo/metabolismo , Axones/metabolismo , Axones/patología , Proteínas del Citoesqueleto/metabolismo , Ratas Sprague-Dawley , Sarín/toxicidad , Sarín/envenenamiento , Nervio Ciático/metabolismoRESUMEN
The peripheral nervous system consists of ganglia, nerve trunks, plexuses, and nerve endings, that transmit afferent and efferent information. Regeneration after a peripheral nerve damage is sluggish and imperfect. Peripheral nerve injury frequently causes partial or complete loss of motor and sensory function, physical impairment, and neuropathic pain, all of which have a negative impact on patients' quality of life. Because the mechanism of peripheral nerve injury and healing is still unclear, the therapeutic efficacy is limited. As peripheral nerve injury research has processed, an increasing number of studies have revealed that biological scaffolds work in tandem with progenitor cells to repair peripheral nerve injury. Here, we fabricated collagen chitosan nerve conduit bioscaffolds together with collagen and then filled neuroepithelial stem cells (NESCs). Scanning electron microscopy showed that the NESCs grew well on the scaffold surface. Compared to the control group, the NESCs group contained more cells with bigger diameters and myelinated structures around the axons. Our findings indicated that a combination of chitosan-collagen bioscaffold and neural stem cell transplantation can facilitate the functional restoration of peripheral nerve tissue, with promising future applications and research implications.
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Quitosano , Colágeno , Regeneración Nerviosa , Traumatismos de los Nervios Periféricos , Andamios del Tejido , Quitosano/química , Regeneración Nerviosa/fisiología , Colágeno/química , Animales , Andamios del Tejido/química , Traumatismos de los Nervios Periféricos/terapia , Ratas , Células Neuroepiteliales/citología , Células-Madre Neurales/citología , Nervios Periféricos/fisiología , Nervio Ciático/fisiologíaRESUMEN
Peripheral nerve blocks provide a safe and reliable alternative in the anesthetic management of femur fractures in elderly subpopulations associated with significant comorbidities. Single-Insertion Multiple Nerve Block Anesthesia (SIMBA) is a technique where a single needle insertion is used to block all four nerves that supply the femur shaft: the femoral nerve, obturator nerve, lateral femoral cutaneous nerve, and sciatic nerve. The authors performed this technique in 11 cardiac compromised geriatric patients with midshaft/distal femur fractures, and the surgery was conducted successfully without any significant hemodynamic change and good postoperative analgesia.
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Fracturas del Fémur , Nervio Femoral , Extremidad Inferior , Bloqueo Nervioso , Humanos , Bloqueo Nervioso/métodos , Anciano , Masculino , Fracturas del Fémur/cirugía , Anciano de 80 o más Años , Femenino , Extremidad Inferior/cirugía , Extremidad Inferior/inervación , Nervio Ciático , Nervio Obturador , Punciones/métodosRESUMEN
INTRODUCTION: In India, the prevalence of diabetes mellitus neuropathy was reported to be as high as 30%. Eight percentage of the diabetic population suffer from foot ulceration and 1.8% have amputations. Popliteal nerve block can be potentially used for foot and ankle surgery with several advantages. AIM: To compare analgesic duration of an ultrasound (US)-guided popliteal sciatic nerve block between diabetics with neuropathy and nondiabetics without neuropathy. PATIENTS AND METHODS: Participants were allocated into two groups for popliteal sciatic nerve blocks under US guidance. The primary outcome was the duration to onset of sensory and motor blockade. The secondary outcome was the duration to rescue analgesic and the visual analog scale scoring within 24 h. Hemodynamic outcomes were also monitored along with the above variables. RESULTS: It was observed that the onset of sensory blockade was faster in participants with diabetes mellitus with peripheral neuropathy as compared to the nondiabetic participants and the duration for onset of motor blockade in dorsiflexion was faster in diabetic patients as compared to the nondiabetic patients (17.48 ± 3.21 min). However, there was no significant changes when comparing the onset of duration to loss of plantar flexion, in diabetics (17.86 ± 2.29 min) versus in nondiabetics (18.51 ± 3.32 min). The duration for rescue analgesics was found to be longer in diabetic participants (13.19 ± 2.14 h) as compared to the nondiabetic participants (11.44 ± 1.86 h). No differences were observed in the hemodynamic changes and the complications associated with local anesthetics in either group. CONCLUSION: Diabetic patients with neuropathy have faster onset of blockade when compared to nondiabetic patients without neuropathy which may be due to the degenerative condition of the peripheral nerves in them. The hemodynamic parameters do not play a role in defining the outcome of the block.
Résumé Introduction:En Inde, la prévalence de la neuropathie liée au diabète sucré atteignait 30 %. Huit pour cent de la population diabétique souffrent d'ulcères du pied et 1,8 % sont amputés. Le bloc du nerf poplité peut être potentiellement utilisé pour la chirurgie du pied et de la cheville avec plusieurs avantages.Objectif:Comparer la durée analgésique d'un bloc du nerf sciatique poplité guidé par échographie (É.-U.) entre des diabétiques atteints de neuropathie et des non diabétiques sans neuropathie.Patients et méthodes:Les participants ont été répartis en deux groupes pour les blocs du nerf sciatique poplité sous la direction des États-Unis. Le critère de jugement principal était la durée jusqu'à l'apparition du blocus sensoriel et moteur. Le résultat secondaire était la durée nécessaire pour sauver l'analgésique et l'échelle visuelle analogique après 24 h. Les résultats hémodynamiques ont également été surveillés avec les variables ci-dessus.Résultats:Il a été observé que l'apparition du blocage sensoriel était plus rapide chez les participants atteints de diabète sucré avec neuropathie périphérique que chez les participants non diabétiques et (la durée d'apparition du blocage moteur en dorsiflexion était plus rapide chez les patients diabétiques que chez les patients non diabétiques (Cependant, il n'y a eu aucun changement significatif en comparant le début de la durée à la perte de flexion plantaire, chez les diabétiques (17,86 ± 2,29 min) versus chez les non diabétiques (18,51 ± 3,32 min). La durée des analgésiques de secours a été trouvée être plus longue chez les participants diabétiques (13,19 ± 2,14 h) par rapport aux participants non diabétiques (11,44 ± 1,86 h). Aucune différence n'a été observée dans les changements hémodynamiques et les complications associées aux anesthésiques locaux dans les deux groupes.Conclusion:Patients diabétiques atteints de neuropathie ont un début de blocage plus rapide que les patients non diabétiques sans neuropathie, ce qui peut être dû à l'état dégénératif des nerfs périphériques chez eux. Les paramètres hémodynamiques ne jouent aucun rôle dans la définition de l'issue du bloc.
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Neuropatías Diabéticas , Bloqueo Nervioso , Nervio Ciático , Humanos , Bloqueo Nervioso/métodos , Masculino , Femenino , Persona de Mediana Edad , Adulto , Dimensión del Dolor , Ultrasonografía Intervencional/métodos , Resultado del Tratamiento , India/epidemiología , Factores de Tiempo , Anestésicos Locales/administración & dosificación , Estudios de Casos y ControlesRESUMEN
Application of polyethylene glycol (PEG) to a peripheral nerve injury at the time of primary neurorrhaphy is thought to prevent Wallerian degeneration via direct axolemma fusion. The molecular mechanisms of nerve fusion and recovery are unclear. Our study tested the hypothesis that PEG alters gene expression in neural and muscular environments as part of its restorative properties. Lewis rats underwent unilateral sciatic nerve transection with immediate primary repair. Subjects were randomly assigned to receive either PEG treatment or standard repair at the time of neurorrhaphy. Samples of sciatic nerve distal to the injury and tibialis muscle at the site of innervation were harvested at 24 hours and 4 weeks postoperatively. Total RNA sequencing and subsequent bioinformatics analyses were used to identify significant differences in differentially expressed genes (DEGs) and their related biological pathways (p<0.05) in PEG-treated subjects compared to non-PEG controls. No significant DEGs were identified in PEG-treated sciatic nerve compared to controls after 24 hours, but 1,480 DEGs were identified in PEG-treated tibialis compared to controls. At 4 weeks, 918 DEGs were identified in PEG-treated sciatic nerve, whereas only 3 DEGs remained in PEG-treated tibialis compared to controls. DEGs in sciatic were mostly upregulated (79%) and enriched in pathways present during nervous system development and growth, whereas DEGs in muscle were mostly downregulated (77%) and related to inflammation and tissue repair. Our findings indicate that PEG application during primary neurorrhaphy leads to significant differential gene regulation in the neural and muscular environment that is associated with improved functional recovery in animals treated with PEG compared to sham non-PEG controls. A detailed understanding of key molecules underlying PEG function in recovery after peripheral nerve repair may facilitate amplification of PEG effects through systemic or focal treatments at the time of neurotmesis.
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Músculo Esquelético , Traumatismos de los Nervios Periféricos , Polietilenglicoles , Ratas Endogámicas Lew , Nervio Ciático , Animales , Ratas , Nervio Ciático/lesiones , Traumatismos de los Nervios Periféricos/genética , Polietilenglicoles/farmacología , Músculo Esquelético/metabolismo , Músculo Esquelético/inervación , Músculo Esquelético/efectos de los fármacos , Modelos Animales de Enfermedad , Análisis de Secuencia de ARN , Regeneración Nerviosa/efectos de los fármacos , Regeneración Nerviosa/genética , Masculino , Regulación de la Expresión Génica/efectos de los fármacos , Perfilación de la Expresión GénicaRESUMEN
OBJECTIVE: Complete resection is the curative treatment choice for recurrent gynecological malignancies. Laterally extended endopelvic resection (LEER) is an effective surgical salvage therapy for lateral recurrence. However, when a recurrent tumor occupies the ischial spine and sacrum, LEER is not indicated, and surgical salvage therapy is abandoned. Theoretically, complete resection of such a tumor is possible by additional pelvic bone resection along with the standard LEER. Nevertheless, owing to the anatomical complexities of the beyond-LEER procedure, 2 major issues should be solved: sciatic nerve injury and tumor disruption during pelvic bone amputation. To overcome these technical challenges, we applied a multidirectional beyond-LEER approach, a novel salvage surgical procedure, with an aim of demonstrating its technical feasibility. METHODS: We created a simulation model of a laterally recurrent tumor that occupied the right ischial spine and sacrum in a Thiel-embalmed cadaver. RESULTS: Multidirectional approaches, including laparoscopic, perineal, and dorsal phases, were safely applied. We laparoscopically marked the L4-L5-S1 complex and S2 nerve with different colored tapes, and by pulling them out into a dorsal surgical field, the sciatic nerve was safely preserved. The dissection lines of the multidirectional approaches were aligned using tapes as landmarks, and complete tumor clearance without tumor disruption was accomplished. By following the cadaveric training, the first laparoscopic-assisted beyond-LEER procedure was successfully performed in a patient with recurrent ovarian cancer. CONCLUSION: Using a Thiel-embalmed cadaver, we demonstrated the technical feasibility of a sciatic nerve-preserved beyond-LEER procedure, which was successfully performed in a patient with recurrent ovarian cancer.
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Cadáver , Recurrencia Local de Neoplasia , Terapia Recuperativa , Nervio Ciático , Humanos , Femenino , Nervio Ciático/cirugía , Recurrencia Local de Neoplasia/cirugía , Terapia Recuperativa/métodos , Neoplasias de los Genitales Femeninos/cirugía , Laparoscopía/métodos , Laparoscopía/educación , Estudios de FactibilidadRESUMEN
Developing bones can adapt their shape in response to mechanical stresses from neighbouring growing organs. In a new study, Koichi Matsuo and colleagues examine how bone-forming osteoblasts and bone-resorbing osteoclasts coordinate growth in the mouse fibula. They describe the process called 'endo-forming trans-pairing', where bone resorption by osteoclasts in the outer periosteum is paired with bone formation by osteoblasts in the inner endosteum to shape the growing bone. To learn more about the story behind the paper, we caught up with first author Yukiko Kuroda and the corresponding author Koichi Matsuo, Professor at the School of Medicine, Keio University, Japan.
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Huesos , Microscopía/métodos , Huesos/citología , Osteoclastos/citología , Osteoclastos/metabolismo , Osteoblastos/citología , Osteoblastos/metabolismo , Nervio Ciático , Desarrollo Óseo , Animales , MorfogénesisRESUMEN
ABSTRACT: Magnetic resonance imaging (MRI) is a potentially powerful novel peripheral nerve diagnosis technique. To determine its validity, in-vivo preclinical studies are necessary. However, when using a rodent model, positioning rats and achieving high-resolution images can be challenging. We present a short report that outlines an optimal protocol for positioning rats for in-vivo MRI acquisition. Female Sprague-Dawley rats with sciatic nerve injury were induced into anesthesia using 4% isoflurane in oxygen and maintained at 1.5%. Rats were placed into a plexiglass cradle in a right lateral recumbent position, and a surface coil was placed over the left leg. Respiration rate and body temperature were monitored throughout the scan. Our protocol was successful as rats were able to undergo MRI scanning safely and efficiently. There were no adverse reactions, and clear images of the left sciatic nerve were obtained. Animal positioning took 30 minutes, and 5 different acquisitions were obtained in 2 hours. The total time from anesthesia induction to recovery was under 3 hours. Given the increasing interest in MRI diagnostic techniques, we hope this report aids other researchers studying peripheral nerve injury imaging in rat models.
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Imagen por Resonancia Magnética , Ratas Sprague-Dawley , Nervio Ciático , Animales , Imagen por Resonancia Magnética/métodos , Femenino , Ratas , Nervio Ciático/lesiones , Nervio Ciático/diagnóstico por imagen , Modelos Animales de Enfermedad , Traumatismos de los Nervios Periféricos/diagnóstico por imagenRESUMEN
The rat sciatic nerve model is commonly used to test novel therapies for nerve injury repair. The static sciatic index (SSI) is a useful metric for quantifying functional recovery, and involves comparing an operated paw versus a control paw using a weighted ratio between the toe spread and the internal toe spread. To calculate it, rats are placed in a transparent box, photos are taken from underneath and the toe distances measured manually. This is labour intensive and subject to human error due to the challenge of consistently taking photos, identifying digits and making manual measurements. Although several commercial kits have been developed to address this challenge, they have seen little dissemination due to cost. Here we develop a novel algorithm for automatic measurement of SSI metrics based on video data using casted U-Nets. The algorithm consists of three U-Nets, one to segment the hind paws and two for the two pairs of digits which input into the SSI calculation. A training intersection over union error of 60 % and 80 % was achieved for the back paws and for both digit segmentation U-Nets, respectfully. The algorithm was tested against video data from three separate experiments. Compared to manual measurements, the algorithm provides the same profile of recovery for every experiment but with a tighter standard deviation in the SSI measure. Through the open-source release of this algorithm, we aim to provide an inexpensive tool to more reliably quantify functional recovery metrics to the nerve repair research community.
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Algoritmos , Modelos Animales de Enfermedad , Traumatismos de los Nervios Periféricos , Animales , Ratas , Traumatismos de los Nervios Periféricos/fisiopatología , Simulación por Computador , Nervio Ciático/fisiología , Nervio Ciático/lesiones , Ratas Sprague-DawleyRESUMEN
This study aimed to investigate the therapeutic potential of human adipose-derived mesenchymal stem cells (hADSCs) modified with recombinant adeno-associated virus (rAAV) carrying the vascular endothelial growth factor 165 (VEGF165) gene in peripheral nerve injury (PNI). The hADSCs were categorized into blank, control (transduced with rAAV control vector), and VEGF165 (transduced with rAAV VEGF165 vector) groups. Subsequently, Schwann cell differentiation was induced, and Schwann cell markers were assessed. The sciatic nerve injury mouse model received injections of phosphate-buffered saline (PBS group), PBS containing hADSCs (hADSCs group), rAAV control vector (control-hADSCs group), or rAAV VEGF165 vector (VEGF165-hADSCs group) into the nerve defect site. Motor function recovery, evaluated through the sciatic function index (SFI), and nerve regeneration, assessed via toluidine blue staining along with scrutiny of Schwann cell markers and neurotrophic factors, were conducted. Modified hADSCs exhibited enhanced Schwann cell differentiation and elevated expression of Schwann cell markers [S100 calcium-binding protein B (S100B), NGF receptor (NGFR), and glial fibrillary acidic protein (GFAP)]. Mice in the VEGF165-hADSCs group demonstrated improved motor function recovery compared to those in the other three groups, accompanied by increased fiber diameter, axon diameter, and myelin thickness, as well as elevated expression of Schwann cell markers (S100B, NGFR, and GFAP) and neurotrophic factors [mature brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF)] in the distal nerve segment. rAAV-VEGF165 modification enhances hADSC potential in PNI, promoting motor recovery and nerve regeneration. Elevated Schwann cell markers and neurotrophic factors underscore therapy benefits, providing insights for nerve injury strategies.
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Diferenciación Celular , Dependovirus , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas , Traumatismos de los Nervios Periféricos , Células de Schwann , Factor A de Crecimiento Endotelial Vascular , Humanos , Dependovirus/genética , Factor A de Crecimiento Endotelial Vascular/metabolismo , Factor A de Crecimiento Endotelial Vascular/genética , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/citología , Animales , Traumatismos de los Nervios Periféricos/terapia , Traumatismos de los Nervios Periféricos/metabolismo , Traumatismos de los Nervios Periféricos/genética , Células de Schwann/metabolismo , Ratones , Regeneración Nerviosa , Tejido Adiposo/citología , Tejido Adiposo/metabolismo , Vectores Genéticos , Nervio Ciático/lesiones , Nervio Ciático/patología , MasculinoRESUMEN
Peripheral nerve injury (PNI) is a complex clinical challenge resulting in functional disability. Neurological recovery does not always ensure functional recovery, as extracellular matrix (ECM) alterations affect muscle function. This study evaluates hyaluronan (HA) and collagen concentration in the gastrocnemius muscle and thoracolumbar fascia (TLF) in unilateral lower limb PNI rats to explore systemic ECM alterations following PNI and their impacts on functional recovery. Eighteen 8-week-old male Sprague-Dawley rats were divided into experimental (n = 12 left sciatic nerve injury) and control (n = 6) groups. After six weeks, motor function was evaluated. Muscle and TLF samples were analysed for HA and collagen distribution and concentrations. SFI and gait analysis confirmed a functional deficit in PNI rats 6 weeks after surgery. HA concentration in both sides of the muscles decreased by approximately one-third; both sides showed significantly higher collagen concentration than healthy rats (12.74 ± 4.83 µg/g), with the left (32.92 ± 11.34 µg/g) significantly higher than the right (20.15 ± 7.03 µg/g). PNI rats also showed significantly lower HA (left: 66.95 ± 20.08 µg/g; right: 112.66 ± 30.53 µg/g) and higher collagen (left: 115.89 ± 28.18 µg/g; right: 90.43 ± 20.83 µg/g) concentrations in both TLF samples compared to healthy rats (HA: 167.18 ± 31.13 µg/g; collagen: 47.51 ± 7.82 µg/g), with the left TLF more affected. Unilateral lower limb PNI induced HA reduction and collagen accumulation in both the lower limb muscles and the TLF, potentially exacerbating motor function impairment and increasing the risk of low back dysfunctions.
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Colágeno , Matriz Extracelular , Fascia , Ácido Hialurónico , Extremidad Inferior , Músculo Esquelético , Ratas Sprague-Dawley , Nervio Ciático , Animales , Matriz Extracelular/metabolismo , Ratas , Masculino , Músculo Esquelético/metabolismo , Fascia/metabolismo , Fascia/patología , Colágeno/metabolismo , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Nervio Ciático/patología , Ácido Hialurónico/metabolismo , Traumatismos de los Nervios Periféricos/metabolismo , Traumatismos de los Nervios Periféricos/patologíaRESUMEN
BACKGROUND: Magnetic resonance neurography (MRN) is increasingly used as a diagnostic tool for peripheral neuropathies. Quantitative measures enhance MRN interpretation but require nerve segmentation which is time-consuming and error-prone and has not become clinical routine. In this study, we applied neural networks for the automated segmentation of peripheral nerves. METHODS: A neural segmentation network was trained to segment the sciatic nerve and its proximal branches on the MRN scans of the right and left upper leg of 35 healthy individuals, resulting in 70 training examples, via 5-fold cross-validation (CV). The model performance was evaluated on an independent test set of one-sided MRN scans of 60 healthy individuals. RESULTS: Mean Dice similarity coefficient (DSC) in CV was 0.892 (95% confidence interval [CI]: 0.888-0.897) with a mean Jaccard index (JI) of 0.806 (95% CI: 0.799-0.814) and mean Hausdorff distance (HD) of 2.146 (95% CI: 2.184-2.208). For the independent test set, DSC and JI were lower while HD was higher, with a mean DSC of 0.789 (95% CI: 0.760-0.815), mean JI of 0.672 (95% CI: 0.642-0.699), and mean HD of 2.118 (95% CI: 2.047-2.190). CONCLUSION: The deep learning-based segmentation model showed a good performance for the task of nerve segmentation. Future work will focus on extending training data and including individuals with peripheral neuropathies in training to enable advanced peripheral nerve disease characterization. RELEVANCE STATEMENT: The results will serve as a baseline to build upon while developing an automated quantitative MRN feature analysis framework for application in routine reading of MRN examinations. KEY POINTS: Quantitative measures enhance MRN interpretation, requiring complex and challenging nerve segmentation. We present a deep learning-based segmentation model with good performance. Our results may serve as a baseline for clinical automated quantitative MRN segmentation.
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Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Adulto , Femenino , Redes Neurales de la Computación , Enfermedades del Sistema Nervioso Periférico/diagnóstico por imagen , Nervio Ciático/diagnóstico por imagen , Nervios Periféricos/diagnóstico por imagen , Nervios Periféricos/anatomía & histología , Persona de Mediana EdadRESUMEN
Neuritin, also known as candidate plasticity gene 15 (CPG15), was first identified as one of the activity-dependent gene products in the brain. Previous studies have been reported that Neuritin induces neuritogenesis, neurite arborization, neurite outgrowth and synapse formation, which are involved in the development and functions of the central nervous system. However, the role of Neuritin in peripheral nerve injury is still unknown. Given the importance and necessity of Schwann cell dedifferentiation response to peripheral nerve injury, we aim to investigate the molecular mechanism of Neuritin steering Schwann cell dedifferentiation during Wallerian degeneration (WD) in injured peripheral nerve. Herein, using the explants of sciatic nerve, an ex vivo model of nerve degeneration, we provided evidences indicating that Neuritin vividly accelerates Schwann cell dedifferentiation. Moreover, we found that Neuritin promotes Schwann cell demyelination as well as axonal degeneration, phagocytosis, secretion capacity. In summary, we first described Neuritin acts as a positive regulator for Schwann cell dedifferentiation and WD after peripheral nerve injury.
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Desdiferenciación Celular , Neuropéptidos , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Células de Schwann , Nervio Ciático , Transducción de Señal , Serina-Treonina Quinasas TOR , Degeneración Walleriana , Células de Schwann/metabolismo , Células de Schwann/patología , Degeneración Walleriana/metabolismo , Degeneración Walleriana/patología , Animales , Serina-Treonina Quinasas TOR/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Neuropéptidos/metabolismo , Neuropéptidos/genética , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Nervio Ciático/patología , Proteínas Ligadas a GPI/metabolismo , Proteínas Ligadas a GPI/genética , Ratas , Traumatismos de los Nervios Periféricos/metabolismo , Traumatismos de los Nervios Periféricos/patología , Ratas Sprague-Dawley , Axones/metabolismo , Axones/patología , Masculino , Fagocitosis , RatonesRESUMEN
Anethole is a terpenoid with antioxidant, anti-inflammatory, and neuronal blockade effects, and the present work was undertaken to study the neuroprotective activity of anethole against diabetes mellitus (DM)-induced neuropathy. Streptozotocin-induced DM rats were used to investigate the effects of anethole treatment on morphological, electrophysiological, and biochemical alterations of the sciatic nerve (SN). Anethole partially prevented the mechanical hyposensitivity caused by DM and fully prevented the DM-induced decrease in the cross-sectional area of the SN. In relation to electrophysiological properties of SN fibers, DM reduced the frequency of occurrence of the 3rd component of the compound action potential (CAP) by 15%. It also significantly reduced the conduction velocity of the 1st and 2nd CAP components from 104.6 ± 3.47 and 39.8 ± 1.02 to 89.9 ± 3.03 and 35.4 ± 1.56 m/s, respectively, and increased the duration of the 2nd CAP component from 0.66 ± 0.04 to 0.82 ± 0.09 ms. DM also increases oxidative stress in the SN, altering values related to thiol, TBARS, SOD, and CAT activities. Anethole was capable of fully preventing all these DM electrophysiological and biochemical alterations in the nerve. Thus, the magnitude of the DM-induced neural effects seen in this work, and the prevention afforded by anethole treatment, place this compound in a very favorable position as a potential therapeutic agent for treating diabetic peripheral neuropathy.
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Derivados de Alilbenceno , Anisoles , Diabetes Mellitus Experimental , Estrés Oxidativo , Nervio Ciático , Animales , Derivados de Alilbenceno/farmacología , Nervio Ciático/efectos de los fármacos , Diabetes Mellitus Experimental/tratamiento farmacológico , Ratas , Anisoles/farmacología , Anisoles/uso terapéutico , Masculino , Estrés Oxidativo/efectos de los fármacos , Ratas Wistar , Neuropatías Diabéticas/tratamiento farmacológico , Neuropatías Diabéticas/prevención & control , Neuropatías Diabéticas/metabolismo , Potenciales de Acción/efectos de los fármacos , Antioxidantes/farmacología , Fármacos Neuroprotectores/farmacología , Fármacos Neuroprotectores/uso terapéuticoRESUMEN
BACKGROUND: Peripheral nerve injury is a challenging orthopedic issue in clinical management that often leads to limb dysfunction or even disability in severe cases. A thorough exploration of the repair process of peripheral nerve injury and the underlying mechanism contributes to formulate more effective therapeutic strategies. METHODS: In the present study, we established a sciatic nerve transection injury model in Sprague-Dawley (SD) rats. A 12-week compensatory repair of sciatic nerve transection injury using a chitin cannula for small gap anastomosis was then performed via sleeve jointing the proximal common peroneal nerve to the distal tibial nerve and common peroneal nerve, with a 2 mm interval. Compensatory repair via small gap amplification was observed via gross observation of nerve specimen, osmic acid staining, and electrophysiological stimulation of sciatic nerve branches of the tibial and common peroneal nerve. Rat limbs were observed, and the functional recovery of effector muscles of the gastrocnemius and tibialis anterior muscles was assessed through weighing the muscle wet weight, Hematoxylin and Eosin (H&E) staining, and muscle strength detection. H&E staining, Masson staining, and toluidine blue staining were performed to observe the morphological changes of the dorsal root ganglion. Positive expressions of key proteins involved in the Phosphatase and tensin homologue deleted on chromosome ten (PTEN)-protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, including PTEN, AKT, mTOR, Toll-like receptor 4 (TLR4), and Caspase9 in the dorsal root ganglion during compensatory repair of sciatic nerve after injury via small gap amplification, were detected by immunohistochemical staining. RESULTS: It is found that the compensatory repair of sciatic nerve transection injury using a chitin cannula for small gap anastomosis via sleeve jointing effectively restored the continuity, number of myelinated nerve fibers, and nerve conduction velocity. It promoted toe abduction recovery, improved muscle fiber morphology and increased the wet weight and muscle strength of the gastrocnemius muscle and tibialis anterior muscle. Moreover, it increased the number of neurons and nerve fibers, and improved their morphology. Downregulated PTEN, TLR4, and Caspase9 in the dorsal root ganglia and upregulated AKT and mTOR were observed after small gap amplification than those of the transection injury group, which were closer to those of the control group. CONCLUSIONS: Compensatory repair of sciatic nerve transection injury using a chitin cannula for small gap anastomosis via sleeve jointing can restore the morphology and function of the sciatic nerve, effector muscles, and corresponding dorsal root ganglia by activating the PTEN-AKT/mTOR signaling pathway in the dorsal root ganglia. Our findings provide novel therapeutic targets for peripheral nerve injuries.
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Ganglios Espinales , Regeneración Nerviosa , Transducción de Señal , Animales , Masculino , Ratas , Modelos Animales de Enfermedad , Ganglios Espinales/metabolismo , Regeneración Nerviosa/fisiología , Traumatismos de los Nervios Periféricos/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Fosfohidrolasa PTEN/metabolismo , Ratas Sprague-Dawley , Nervio Ciático/lesiones , Neuropatía Ciática/metabolismo , Transducción de Señal/fisiología , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
Peripheral nerve injury (PNI) often leads to retrograde cell death in the spinal cord and dorsal root ganglia (DRG), hindering nerve regeneration and functional recovery. Repetitive magnetic stimulation (rMS) promotes nerve regeneration following PNI. Therefore, this study aimed to investigate the effects of rMS on post-injury neuronal death and nerve regeneration. Seventy-two rats underwent autologous sciatic nerve grafting and were divided into two groups: the rMS group, which received rMS and the control (CON) group, which received no treatment. Motor neuron, DRG neuron, and caspase-3 positive DRG neuron counts, as well as DRG mRNA expression analyses, were conducted at 1-, 4-, and 8-weeks post-injury. Functional and axon regeneration analyses were performed at 8-weeks post-injury. The CON group demonstrated a decreased DRG neuron count starting from 1 week post-injury, whereas the rMS group exhibited significantly higher DRG neuron counts at 1- and 4-weeks post-injury. At 8-weeks post-injury, the rMS group demonstrated a significantly greater myelinated nerve fiber density in autografted nerves. Furthermore, functional analysis showed significant improvements in latency and toe angle in the rMS group. Overall, these results suggest that rMS can prevent DRG neuron death and enhance nerve regeneration and motor function recovery after PNI.
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Muerte Celular , Modelos Animales de Enfermedad , Ganglios Espinales , Regeneración Nerviosa , Traumatismos de los Nervios Periféricos , Nervio Ciático , Animales , Ganglios Espinales/metabolismo , Ratas , Nervio Ciático/lesiones , Traumatismos de los Nervios Periféricos/terapia , Masculino , Ratas Sprague-Dawley , Neuronas/metabolismo , Magnetoterapia/métodos , Recuperación de la Función , Neuronas Motoras/metabolismo , Neuronas Motoras/fisiologíaRESUMEN
AIM: To evaluate the effects of tramadol on inflammation by measuring NLRP1 and IL-1 beta (IL-1ß) levels in an experimental neuropathic pain model. MATERIAL AND METHODS: Sprague-Dawley rats were divided into three groups: control, chronic constriction injury (CCI), and CCI + tramadol. Neuropathic pain was assessed using mechanical allodynia, thermal hyperalgesia, and cold allodynia. IL-1ß and NLRP1 levels were evaluated using ELISA on sciatic nerve (SN), dorsal root ganglion (DRG), and serum either on day 3 or days 8 postsurgery. RESULTS: On day 3, paw withdrawal latency (PWL) was lower in the CCI and CCI + tramadol groups than the control group in both mechanical and cold allodynia tests. On day 8, the PWL in the CCI group was also lower than in the control group. In contrast, tramadol increased the PWL on day 8 compared to day 3 in the CCI group. During cold allodynia, PWL decreased in the CCI group, however, tramadol reversed this effect on days 3 and 8. Tramadol, therefore, ameliorated pain hypersensitivity in mechanical/cold allodynia tests. Serum IL-1ß levels were higher in the CCI + tramadol and CCI groups than the control group, although serum IL-1ß levels in the CCI and CCI + tramadol groups were comparable. Tramadol decreased the IL-1ß and NLRP1 in DRG compared with the CCI group. A similar trend was observed in the SN samples. CONCLUSION: Our experiments revealed an increase in IL-1ß and NLRP-1 levels in a neuropathic pain model and found that tramadol had an anti-inflammatory effect on the IL-1ß and NLRP1 inflammasomes.
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Modelos Animales de Enfermedad , Hiperalgesia , Inflamasomas , Interleucina-1beta , Neuralgia , Ratas Sprague-Dawley , Tramadol , Animales , Tramadol/farmacología , Tramadol/uso terapéutico , Interleucina-1beta/metabolismo , Interleucina-1beta/sangre , Neuralgia/tratamiento farmacológico , Neuralgia/metabolismo , Inflamasomas/efectos de los fármacos , Inflamasomas/metabolismo , Masculino , Hiperalgesia/tratamiento farmacológico , Hiperalgesia/metabolismo , Ratas , Analgésicos Opioides/farmacología , Nervio Ciático/efectos de los fármacos , Ganglios Espinales/efectos de los fármacos , Ganglios Espinales/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas del Tejido NerviosoRESUMEN
Immune cells are critical in promoting neuroinflammation and neuropathic pain and in facilitating pain resolution, depending on their inflammatory and immunoregulatory cytokine response. Interleukin (IL)-35, secreted by regulatory immune cells, is a member of the IL-12 family with a potent immunosuppressive function. In this study, we investigated the effects of IL-35 on pain behaviors, spinal microglia phenotype following peripheral nerve injury, and in vitro microglial cultures in male and female mice. Intrathecal recombinant IL-35 treatment alleviated mechanical pain hypersensitivity prominently in male mice, with only a modest effect in female mice after sciatic nerve chronic constriction injury (CCI). IL-35 treatment resulted in sex-specific microglial changes following CCI, reducing inflammatory microglial markers and upregulating anti-inflammatory markers in male mice. Spatial transcriptomic analysis revealed that IL-35 suppressed microglial complement activation in the superficial dorsal horn in male mice after CCI. Moreover, in vitro studies showed that IL-35 treatment of cultured inflammatory microglia mitigated their hypertrophied morphology, increased their cell motility, and decreased their phagocytic activity, indicating a phenotypic shift towards homeostatic microglia. Further, IL-35 altered microglial cytokines/chemokines in vitro, suppressing the release of IL-9 and monocyte-chemoattractant protein-1 and increasing IL-10 in the supernatant of male microglial cultures. Our findings indicate that treatment with IL-35 modulates spinal microglia and alleviates neuropathic pain in male mice, suggesting IL-35 as a potential sex-specific targeted immunomodulatory treatment for neuropathic pain.
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Interleucinas , Microglía , Neuralgia , Traumatismos de los Nervios Periféricos , Animales , Masculino , Microglía/metabolismo , Microglía/efectos de los fármacos , Ratones , Neuralgia/metabolismo , Neuralgia/tratamiento farmacológico , Interleucinas/metabolismo , Femenino , Traumatismos de los Nervios Periféricos/metabolismo , Traumatismos de los Nervios Periféricos/complicaciones , Ratones Endogámicos C57BL , Citocinas/metabolismo , Médula Espinal/metabolismo , Médula Espinal/efectos de los fármacos , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Hiperalgesia/metabolismo , Hiperalgesia/tratamiento farmacológico , Antiinflamatorios/farmacología , Modelos Animales de Enfermedad , Inflamación/metabolismoRESUMEN
The development of biomaterials such as synthetic scaffolds for peripheral nerve regeneration requires a precise knowledge of the mechanical properties of the nerve in physiological-like conditions. Mechanical properties (Young's modulus, maximum stress and strain at break) for peripheral nerves are scarce and large discrepancies are observed in between reports. This is due in part to the absence of a robust testing device for nerves. To overcome this limitation, a custom-made tensile device (CMTD) has been built. To evaluate its reproducibility and accuracy, the imposed speed and distance over measured speed and distance was performed, followed by a validation using poly(dimethylsiloxane) (PDMS), a commercial polymer with established mechanical properties. Finally, the mechanical characterization of rodents (mice and rats) sciatic nerves using the CMTD was performed. Mouse and rat sciatic nerves Young's modulus were 4.57 ± 2.04 and 19.2 ± 0.86 MPa respectively. Maximum stress was 1.26 ± 0.56 MPa for mice and 3.81 ± 1.84 MPa for rats. Strain at break was 53 ± 17% for mice and 32 ± 12% for rats. The number of axons per sciatic nerve was found to be twice higher for rats. Statistical analysis of the measured mechanical properties revealed no sex-related trends, for both mice and rats (except for mouse maximum stress with p=0.03). Histological evaluation of rat sciatic nerve corroborated these findings. By developing a robust CMTD to establish the key mechanical properties (Young's modulus, maximum stress and strain at break) values for rodents sciatic nerves, our work represent an essential step toward the development of better synthetic scaffolds for peripheral nerve regeneration.