Time-dependent proregenerative effects of exogenous melatonin on the transected sciatic nerve / Efectos proregenerativos dependientes del tiempo de la melatonina exógena en el nervio ciático seccionado

SUMMARY: Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Los procedimientos microquirúrgicos son el tratamiento de elección de las lesiones de los nervios periféricos, pero a menudo no logran una recuperación funcional completa. La melatonina tiene acciones neuroprotectoras y podría ser utilizada como un posible apoyo farmacológico proregenerativo. Por lo tanto, el objetivo de este estudio fue analizar la dependencia del tiempo del efecto neuroprotector de la melatonina sobre las estructuras fasciculares generales de ambos extremos del nervio seccionado. La sección del nervio ciático se realizó en 34 ratas Wistar macho adultas divididas en cuatro grupos: dos grupos de vehículo (N=7) tratados por vía intraperitoneal durante 7 (V7) o 21 (V21) días consecutivos con vehículo (5 % de etanol en solución Ringer) y dos grupos grupos de melatonina (N=10) a los que se les administró por vía intraperitoneal 30 mg/kg de melatonina durante 7 (M7) o 21 (M21) días consecutivos. Al final del experimento, se extirparon y procesaron el neuroma del muñón proximal y el fibroma del muñón distal del nervio para un análisis histológico cualitativo y cuantitativo. Las estructuras neurales intrafasciculares se conservaron mejor y el depósito de colágeno se redujo en los grupos tratados con melatonina respecto a los grupos con vehículo. La regeneración de la vaina de mielina observada a través de la medición de su espesor fue estadísticamente significativa (p<0,05) más pronunciada en el grupo M21 (1,23±0,18 µm) vs V21 (0,98±0,13 µm). La densidad de volumen media del endoneuro fue menor en ambos grupos tratados con melatonina en comparación con los grupos tratados con vehículo equivalente. Aunque no fue estadísticamente diferente, el diámetro del tubo endoneural fue mayor en ambos grupos de melatonina frente a los grupos de vehículo, y el efecto de la melatonina fue más pronunciado después de 21 días (aumento del 24,97 %) frente a los 7 días de tratamiento con melatonina (18,8 % de aumento). La melatonina ejerce un efecto proregenerativo dependiente del tiempo sobre las fibras nerviosas del muñón proximal y un efecto anticicatricial en ambos muñones.

Effect of folic acid coated-crosslinked urethane-doped polyester elastomer nerve conduit on promoting the repair of long distance peripheral nerve injury in rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury.@*METHODS@#Thirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group.@*RESULTS@#At 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation ( P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation ( P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation ( P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation ( P<0.05). There was no significant difference between groups B and C at each time point after operation ( P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm 2, which was significantly more than that in group A [(298.33±153.12) cells/mm 2] ( t=6.139, P<0.001).@*CONCLUSION@#The fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.

Transcriptome Analysis of Schwann Cells at Various Stages of Myelination Implicates Chromatin Regulator Sin3A in Control of Myelination Identity / 神经科学通报·英文版

Enhancing remyelination after injury is of utmost importance for optimizing the recovery of nerve function. While the formation of myelin by Schwann cells (SCs) is critical for the function of the peripheral nervous system, the temporal dynamics and regulatory mechanisms that control the progress of the SC lineage through myelination require further elucidation. Here, using in vitro co-culture models, gene expression profiling of laser capture-microdissected SCs at various stages of myelination, and multilevel bioinformatic analysis, we demonstrated that SCs exhibit three distinct transcriptional characteristics during myelination: the immature, promyelinating, and myelinating states. We showed that suppressor interacting 3a (Sin3A) and 16 other transcription factors and chromatin regulators play important roles in the progress of myelination. Sin3A knockdown in the sciatic nerve or specifically in SCs reduced or delayed the myelination of regenerating axons in a rat crushed sciatic nerve model, while overexpression of Sin3A greatly promoted the remyelination of axons. Further, in vitro experiments revealed that Sin3A silencing inhibited SC migration and differentiation at the promyelination stage and promoted SC proliferation at the immature stage. In addition, SC differentiation and maturation may be regulated by the Sin3A/histone deacetylase2 (HDAC2) complex functionally cooperating with Sox10, as demonstrated by rescue assays. Together, these results complement the recent genome and proteome analyses of SCs during peripheral nerve myelin formation. The results also reveal a key role of Sin3A-dependent chromatin organization in promoting myelinogenic programs and SC differentiation to control peripheral myelination and repair. These findings may inform new treatments for enhancing remyelination and nerve regeneration.

Protective effect of Epothilone D against traumatic optic nerve injury in rats / 南方医科大学学报

OBJECTIVE@#To investigate the therapeutic effect of Epothilone D on traumatic optic neuropathy (TON) in rats.@*METHODS@#Forty-two SD rats were randomized to receive intraperitoneal injection of 1.0 mg/kg Epothilone D or DMSO (control) every 3 days until day 28, and rat models of TON were established on the second day after the first administration. On days 3, 7, and 28, examination of flash visual evoked potentials (FVEP), immunofluorescence staining and Western blotting were performed to examine the visual pathway features, number of retinal ganglion cells (RGCs), GAP43 expression level in damaged axons, and changes of Tau and pTau-396/404 in the retina and optic nerve.@*RESULTS@#In Epothilone D treatment group, RGC loss rate was significantly decreased by 19.12% (P=0.032) on day 3 and by 22.67% (P=0.042) on day 28 as compared with the rats in the control group, but FVEP examination failed to show physiological improvement in the visual pathway on day 28 in terms of the relative latency of N2 wave (P=0.236) and relative amplitude attenuation of P2-N2 wave (P=0.441). The total Tau content in the retina of the treatment group was significantly increased compared with that in the control group on day 3 (P < 0.001), showing a consistent change with ptau-396/404 level. In the optic nerve axons, the total Tau level in the treatment group was significantly lower than that in the control group on day 7 (P=0.002), but the changes of the total Tau and pTau-396/404 level did not show an obvious correlation. Epothilone D induced persistent expression of GAP43 in the damaged axons, detectable even on day 28 of the experiment.@*CONCLUSION@#Epothilone D treatment can protect against TON in rats by promoting the survival of injured RGCs, enhancing Tau content in the surviving RGCs, reducing Tau accumulation in injured axons, and stimulating sustained regeneration of axons.

Mechanical properties of the sciatic nerve following combined transplantation of analytically extracted acellular allogeneic nerve and adipose-derived mesenchymal stem cells

Abstract Purpose To investigate the effects of Chemically Extracted Acellular Nerves (CEANs) when combined with Adipose-Derived mesenchymal Stem Cell (ADSC) transplantation on the repair of sciatic nerve defects in rabbits. Methods A total of 71 six-month-old Japanese rabbit were used in this study. Twenty rabbits served as sciatic nerve donors, while the other 51 rabbits were randomly divided into Autologous Nerve Transplantation Group (ANT, n=17), CEAN group (n=17) and CEAN-ADSCs group (n=17). In all these groups, the rabbit's left sciatic nerves were injured before the experiment, and the uninjured sciatic nerves on their right side were used as the control (CON). Electrophysiological tests were carried out and sciatic nerves were prepared for histomorphology and stretch testing at 24 weeks post-transplant. Results There were significant differences between ANT and Con groups in amplitude (AMP): P=0.031; motor nerve conduction velocity (MNCV): P=0.029; Maximum stress: P=0.029; and Maximum strain P=0.027. There were also differences between the CEAN and CEAN+ADSCs groups in AMP: P=0.026, MNCV: P=0.024; Maximum stress: P=0.025 and Maximum strain: P=0.030. No significant differences in these parameters were observed when comparing the ANT and CEAN+SACN groups (MNCV: P=0.071) or the CEAN and ANT groups (Maximum stress: P=0.069; Maximum strain P=0.077). Conclusion Addition of ADSCs has a significant impact on the recovery of nerve function, morphology, and tensile mechanical properties following sciatic nerve injury.

Effects of growth hormone in the central nervous system

ABSTRACT Growth hormone (GH) is best known for its effect stimulating tissue and somatic growth through the regulation of cell division, regeneration and proliferation. However, GH-responsive neurons are spread over the entire central nervous system, suggesting that they have important roles in the brain. The objective of the present review is to summarize and discuss the potential physiological importance of GH action in the central nervous system. We provide evidence that GH signaling in the brain regulates the physiology of numerous functions such as cognition, behavior, neuroendocrine changes and metabolism. Data obtained from experimental animal models have shown that disruptions in GH signaling in specific neuronal populations can affect the reproductive axis and impair food intake during glucoprivic conditions, neuroendocrine adaptions during food restriction, and counter-regulatory responses to hypoglycemia, and they can modify gestational metabolic adaptions. Therefore, the brain is an important target tissue of GH, and changes in GH action in the central nervous system can explain some dysfunctions presented by individuals with excessive or deficient GH secretion. Furthermore, GH acts in specific neuronal populations during situations of metabolic stress to promote appropriate physiological adjustments that restore homeostasis. Arch Endocrinol Metab. 2019;63(6):549-56

Does neuroectodermal stem cells transplantation restore neural regeneration and locomotor functions in compressed spinal cord injury rat model? / ¿El trasplante de células madre neuroectodérmicas restaura la regeneración neural y las funciones locomotoras en el modelo de rata con lesión de la médula espinal comprimida?

SUMMARY: The aim of this study was to determine the possible regenerative effect of neuroectodermal stem cells on the ultrastructural, and locomotor function resulting from compressed injury to the spinal cord in a rat model. Forty male rats were divided into control and sham groups (20 rats each). Compressed spinal cord injured (CSCI) were forty rats which subdivided equally into: untreated, treated by neuroectodermal stem cells (NESCs). After four weeks, all rats in different groups were scarified, samples were taken from central, cranial, and caudal to the site of spinal cord injury. Specimens were prepared for light and electron microscopic examination. The number of remyelinated axons in central, cranial and caudal regions to the injured spinal cord after transplantation of NESCs was counted. The open field test assessed the locomotor function. Results revealed that compressed spinal cord injury resulted in loss and degeneration of numerous nerve fibers, myelin splitting and degeneration of mitochondria. Four weeks after transplantation of NESCs regenerated axons were noticed in cranial and central sites, while degenerate axons were noticed caudal to the lesion. Number of remyelinated axons was significantly increased in both central and cranial to the site of spinal cord injury in comparison with caudal region which had the least number of remyelinated axons. Transplantation of NESCs improved significantly the locomotor functional activity In conclusion, neuroectodermal stem cells transplantation ameliorated the histopathological and ultrastructural changes, and improved the functional locomotor activity in CSCI rat.

RESUMEN: El objetivo de este estudio fue determinar el posible efecto regenerativo de las células madre neuroectodérmicas en la función ultraestructural y locomotora de una lesión comprimida en la médula espinal en un modelo de rata. Cuarenta ratas macho se dividieron en grupos control y sham (20 ratas en cada grupo). La médula espinal lesionada (CSCI) tenía cuarenta ratas que se subdividieron de igual forma en los siguientes grupos: no tratadas, tratadas con células madre neuroectodérmicas (NESCs). Al término de cuatro semanas, todas las ratas en los diferentes grupos fueron escarificadas, se tomaron muestras de las áreas central, craneal y caudal en relación al sitio de la lesión de la médula espinal. Las muestras fueron preparadas para examen microscópico de luz y electrónica. Se contó el número de axones remielinizados en las regiones central, craneal y caudal de la médula espinal lesionada después del trasplante de NESCs. La prueba de campo abierto evaluó la función locomotora. Los resultados revelaron que la lesión de la médula espinal comprimida provocó la pérdida y degeneración de numerosas fibras nerviosas, la división de la mielina y la degeneración de las mitocondrias. Cuatro semanas después del trasplante de NESCs, se notaron axones regenerados en los sitios craneales y centrales, mientras que los axones degenerados se notaron caudal a la lesión. El número de axones remielinizados aumentó significativamente tanto en el centro como en el cráneo hasta el sitio de la lesión de la médula espinal en comparación con la región caudal que tenía el menor número de axones remielinizados. El trasplante de NESCs mejoró significativamente la actividad funcional locomotora. En conclusión, el trasplante de células madre neuroectodérmicas mejoró los cambios histopatológicos y ultraestructurales, y mejoró la actividad locomotora funcional en la rata CSCI.

End-to-side versus end-to-end neurorrhaphy at the peroneal nerve in rats

Abstract Purpose: To evaluate three different kinds of neurorrhaphy of the peroneal nerve. Methods: Eigthy rats were divided into 5 groups. Control: nerve had no intervention. End-to-end (EE): nerve was cut and elongated with a nerve graft with two end-to-end neurorrhaphies. End-to-side (ES): nerve was cut and sutured to the graft with at the lateral side of the nerve. Side-to-end (SE): the nerve was cut and sutured to the graft with end-to-end neurorrhaphy. Denervated: nerve was cut and both endings were buried into the muscle. The evaluation was done by walking track analysis, electrophysiology, body mass, cranial tibial muscle mass, nerve and muscle fibers morphometry. Results: The EE, ES and SE have the same potential of reinnervation. Conclusion: There is no functional or histological difference between these different types of neurorrhaphy.

Correlation between motor function recovery and daily living activity outcomes after brachial plexus surgery / Correlação entre a recuperação motora funcional e as atividades de vida diária após cirurgia do plexo braquial

ABSTRACT Objective To establish the correlation between clinical evaluation of motor function recovery and daily living activities in 30 patients with upper traumatic brachial plexus injury submitted to surgery. Methods The score of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and the Louisiana State University Health Sciences Center (LSUHSC) scale were determined in 30 patients. Epidemiologic factors were also examined and correlations were determined. Results There was a significant correlation between the clinical evaluation and the daily living activities after a 12-month period (r = 0.479 and p = 0.007). A direct correlation was observed between the functional recovery of the upper limb and the time between injury and surgery (r = 0.554 and p = 0.001). The LSUHSC scores (p = 0.049) and scores from the DASH questionnaire (p = 0.013) were better among patients who returned to work. Conclusions Clinical evaluation and daily living activities in adult patients who underwent nerve transfer after brachial plexus injury showed significant and measurable improvements.

RESUMO Objetivo Avaliar a correlação entre a avaliação clínica e as atividades de vida diária em 30 paciente adultos com lesão do plexo braquial superior. Métodos O valor do questionário Dash (Disabilities of the Arm, Shoulder and Hand) e da escala Louisiana State University Health Sciences Center (LSUHSC) foram quantificados prospectivamente em 30 pacientes. Fatores epidemiológicos foram também examinados e correlações específicas determinadas. Resultados Houve correlação significativa entre avaliação clínica e as atividades de vida diária 12 meses após a cirurgia (r = 0.479 e p = 0.007). Uma correlação direta foi observada entre a recuperação funcional do membro superior e o tempo entre a lesão e a cirurgia (r = 0.554 e p = 0.001). Os valores da escala LSUHSC (p = 0.049) e do DASH (p = 0.013) foram melhores entre aqueles que retornaram ao trabalho. Conclusões A avaliação clínica e as atividades de vida diária em pacientes submetidos à cirurgia de transferência de nervos após lesão do plexo braquial mostraram correlação significativa.

Inside-out and standard vein grafts associated with platelet-rich plasma (PRP) in sciatic nerve repair. A histomorphometric study

Abstract Purpose: To evaluated the tubulization technique with standard and inside-out vein, filled or not with platelet-rich plasma (PRP), in sciatic nerve repair. Methods: Seventy male Wistar rats were randomly divided into five groups: IOVNF (Inside-Out Vein with No Filling); IOVPRP (Inside-Out Vein filled with PRP); SVNF (Standard Vein with No Filling); SVPRP (Standard Vein filled with PRP); Sham (Control). The left external jugular vein was used as graft in a 10 mm nervous gap. Results: In the morphological analysis of all groups, myelinated nerve fibers with evident myelin sheath, neoformation of the epineurium and perineurium, organization of intraneural fascicles and blood vessels were observed. In the morphometry of the distal stump fibers, SVPRP group had the highest means regarding fiber diameter (3.63±0.42 μm), axon diameter (2.37±0.31 μm) and myelin sheath area (11.70±0.84 μm2). IOVPRP group had the highest means regarding axon area (4.39±1.16 μm2) and myelin sheath thickness (0.80±0.19 μm). As for values of the fiber area, IOVNF group shows highest means (15.54±0.67 μm2), but are still lower than the values of the Sham group. Conclusion: The graft filled with platelet-rich plasma, with use standard (SVPRP) or inside-out vein (IOVPRP), promoted the improvement in axonal regeneration on sciatic nerve injury.

Comparative study between standard and inside-out vein graft techniques on sciatic nerve repair of rats. Muscular and functional analysis

Abstract Purpose: To compare the functional result of standart vein grafts and inside-out vein graft technique on sciatic nerve repair. Methods: We used 24 male Wistar rats divided into 4 groups: control group (CG), standard vein graft group (SVG), Inside-out vein graft group (IOVG) and denervated Group (DG). SVG, IOVG and DG underwent total section of the sciatic nerve, SVG and IOVG however underwent nerve repair surgery using a graft with normal jugular vein and inside-out jugular vein, respectively. Histological analysis of the soleus and Extensor Digitorum Longus (EDL), and Sciatic Functional Index were used to compare the results after 6 weeks. Results: Both grafts acted favorably in muscle recovery and improved functionality; They were similar in all parameters, however, in more points SVG achieved similar to the CG, in the other hand IOVG more times was similar to DG. Fact that makes the graft with normal vein the most viable option between the two options. Conclusion: Both types of grafts acted beneficially wherein the graft normal vein has proved to be the best option

PPE tube filled with autologous fat in the repair of peripheral nerve: a new proposal / Tubo PPE relleno con grasa autóloga en la reparación de los nervios periféricos: una nueva propuesta

This study proposes the use of a porous polyethylene (PPE) tube as the conductive element in the regeneration in the sciatic nerve sectioning and evaluates the use of fill with autologous fat. The subject was divided randomly into five groups, 3 control and 2 experimental (PPE tube graft with/ without autologous fat). Each group was selected for functional, histological and morphometric evaluation of the sciatic nerve. Functional analysis of the sciatic nerve occurred through the "footprint" values near -100 refer sectioned sciatic nerve, near 0 (zero) refer to control group. On histological analysis of the experimental groups lots of dense connective tissue replacing nerve tissue was observed. In morphometric analysis the group EGPGf got higher performance in all of variables. The use of PPE has shown promise in nerve regeneration with favorable results when associate with fat as a trophic factor in the regeneration.

Este estudio propone el uso de un tubo de polietileno poroso (PPE) como elemento conductor en la regeneración del nervio ciático seccionado y evaluar el uso de relleno con grasa autóloga. Al azar se formaron cinco grupos, 3 y 2 de control experimental (PPE prótesis tubular con / sin grasa autóloga). Cada grupo fue seleccionado para estudiar la forma funcional, histológica y evaluación morfométrica del nervio ciático. Un análisis funcional del nervio ciático se produjo a través de los valores de "huella", cerca de -100 se refiere al nervio ciático seccionado; cerca de 0 (cero) se refiere al grupo control. En el análisis histológico de los grupos experimentales se observó una gran cantidad de tejido conjuntivo denso que sustituye el tejido nervioso. En el análisis morfométrico, el grupo experimental de injerto de polietileno lleno de grasa (EGPGf) obtuvo un mayor rendimiento en todas las variables. El uso de PPE ha mostrado ser prometedor en la regeneración del nervio, con resultados favorables cuando se asocia con la grasa como un factor trófico en la regeneración.

Combined polyglycolic acid tube and autografting versus autografting or polyglycolic acid tube alone. A comparative study of peripheral nerve regeneration in rats

PURPOSE: To compare sciatic nerve regeneration in rats using three different techniques of repair. METHODS: Fifteen isogonics rats were divided into three groups according to the method used to repair a 5-mm long defect created in the sciatic nerve: autogenous graft (Group A), polyglycolic acid tube (PGAt) (Group B), and of the association of PGAt with the graft (Group C). Histological analysis, regenerated myelinated axon number count and functional analysis were used to compare after six weeks. RESULTS: There was no difference in fiber diameter and degree of myelinization presented by Groups A, B and C. Group B presented the lowest number of regenerated axons. The groups did not display any significant functional difference after walking track analysis (p<0.05). CONCLUSION: No differences between the three groups in terms of functional recovery, although there were histological differences among them. .

Enxerto com tubo de polietileno poroso preenchido com gordura autóloga no reparo de nervo periférico associado com protocolo de imersão em câmara hiperbárica / Graft with porous polyethylene rod filled with autologous adipocytes in peripheral nerve repair associated with immersion in hyperbaric chamber

Os nervos periféricos são extensões do sistema nervoso central e responsável pela interação das atividades entre as extremidades, em suas funções sensitivas e motoras. São vulneráveis aos mesmos tipos de traumas que afetam outros tecidos: contusão, compressão, esmagamento, estiramento, avulsão e laceração. As lesões de nervos periféricos situam-se entre as mais incapacitantes que acometem indivíduos em idade produtiva, em face dos múltiplos aspectos concernentes às sequelas deste tipo de afecção. Desta forma, a interrupção de continuidade da estrutura do nervo, como no caso da neurotmese, por algum tipo de trauma, resulta na interrupção de transmissão dos impulsos nervosos e na desorganização de suas atividades funcionais. Por meio da utilização da microcirurgia foi possível desenvolver técnicas reparadoras que vão desde simples neurorrafia término-terminal até sofisticados procedimentos cirúrgicos com a utilização de enxertos de nervos, veias e artérias invertidas, tubos sintéticos de materiais variados, tais como silicone e polietileno. Outro aspecto que intriga pesquisadores de todo mundo é a utilização de fatores neurogênicos capazes de acelerar ou melhorar a regeneração de nervos periféricos. A gordura autóloga tem sido continuamente referenciada pela sua abundante oferta, no próprio sitio cirúrgico, apresentando resultados promissores, visto que a adventícia dos vasos é constituída por tecido conjuntivo frouxo, rico em adipócitos. Assim, em um trauma, os neuritos oriundos do coto proximal do nervo lesado, ficam diretamente em contato com esses adipócitos. Seguindo este raciocínio, e com base em trabalhos anteriores onde foi usada veia preenchida com músculo esquelético a fresco como enxerto, decidiu-se testar a possibilidade de crescimento axonal por meio de enxerto com tubo de polietileno preenchido por tecido adiposo autólogo associado a protocolo de imersão em câmara hiperbárica, por meio de um estudo Randomizado Controlado...

The peripheral nerves are extensions of the central nervous system and are responsible for the sensory and motor functions of the limbs. These nerves are vulnerable to the same types of traumas that affect other tissues: contusion, compression, crushing, stretching, avulsion, and laceration. Amongst the most disabling kinds of injuries that affect working-age individuals are those of the peripheral nerves; due to the multifaceted characteristics of the aftereffects of the injury. The break in continuity of the nerve structure due to trauma, as in the case of neurotmesis, results in the disruption of the transmission of nerve impulses and the disorganization of their functions. Through the use of microsurgery, it was possible to develop reconstructive techniques that range from a simple end-to-end neurorrhaphy to sophisticated surgical procedures that utilize nerve grafts, inverted veins and arteries, and synthetic rods of varied materials such as silicone or porous polyethylene. Another aspect that intrigues researchers around the world is the utilization of neurogenic factors capable of accelerating or improving the regeneration of peripheral nerves. Autologous fat has been a constant reference in this field of surgery due to its abundant supply at the surgical site itself. The results are promising, as the adventitia of vessels consists of loose connective tissue rich in adipocytes. Thus in a trauma, the neurites derived from the proximal stump of the damaged nerve are in direct contact with these adipocytes. Following this reasoning, and based on previous studies where veins grafted with fresh skeletal muscle were used, we decided to conduct a randomized controlled study to test the possibility of axonal growth by means of grating with a polyethylene rod filled with autologous adipocytes associated with immersion in a hyperbaric chamber. In an attempt to recover the sciatic nerve, a rod 12 mm in length, with a diameter of 0.25 mm, and with pores...

Regeneración axonal posterior a lesiones traumáticas de médula espinal: Papel crítico de galectina-1

Al producirse una lesión de médula espinal (LME), un sinnúmero de proteínas inhibidoras de la regeneración axonal ocupan el sitio de lesión en forma secuencial. La primer proteína en llegar al mismo se conoce como semaforina 3A (Sema3A), siendo además una de las más potentes por su acción de inhibir la regeneración axonal. A nivel mecanístico la unión de esta proteína al complejo-receptor neuronal neuropilin-1 (NRP-1)/PlexinA4 evita que se produzca regeneración axonal. En este trabajo de revisión se discutirá la acción de galectin-1 (Gal-1), una proteína endógena de unión a glicanos, que selectivamente se une al complejo-receptor NRP-1/PlexinA4 de las neuronas lesionadas a través de un mecanismo dependiente de interacciones lectina-glicano, interrumpiendo la señalización generada por Sema3A y permitiendo de esta manera la regeneración axonal y recuperación locomotora luego de producirse la LME. Mientras ambas formas de Gal-1 (monomérica y dimérica) contribuyen a la inactivación de la microglia, solo la forma dimérica de Gal-1 es capaz de unirse al complejo-receptor NRP-1/PlexinA4 y promover regeneración axonal. Por lo tanto, Gal-1 dimérica produce recuperación de las lesiones espinales interfiriendo en la señalización de Sema3A a través de la unión al complejo-receptor NRP-1/PlexinA4, sugiriendo el uso de esta lectina en su forma dimérica para el tratamiento de pacientes con LME.

When spinal cord injury (SCI) occurs, a great number of inhibitors of axonal regeneration consecutively invade the injured site. The first protein to reach the lesion is known as semaphorin 3A (Sema3A), which serves as a powerful inhibitor of axonal regeneration. Mechanistically binding of Sem3A to the neuronal receptor complex neuropilin-1 (NRP-1) / PlexinA4 prevents axonal regeneration. In this special article we review the effects of galectin-1 (Gal-1), an endogenous glycan-binding protein, abundantly present at inflammation and injury sites. Notably, Gal1 adheres selectively to the NRP-1/PlexinA4 receptor complex in injured neurons through glycan-dependent mechanisms, interrupts the Sema3A pathway and contributes to axonal regeneration and locomotor recovery after SCI. While both the monomeric and dimeric forms of Gal-1 contribute to ’switch-off’ classically-activated microglia, only dimeric Gal-1 binds to the NRP-1/PlexinA4 receptor complex and promotes axonal regeneration. Thus, dimeric Gal-1 promotes functional recovery of spinal lesions by interfering with inhibitory signals triggered by Sema3A adhering to the NRP-1/PlexinA4 complex, supporting the use of dimeric Gal-1 for the treatment of SCI patients.

Reparo do nervo facial com sutura epineural térmico-terminal e coaptação com adesivo de fibrina em ratos associado ou não a laserterapia / Repair of facial nerve with epineural end-to-end suture and coaptation with fibrin adhesive in rats associated or not laser therapy

As lesões que envolvem nervos periféricos, especialmente os traumatismos facias, são muito comuns e decorrentes principalmente de acidentes com veículos motorizados, lesões acidentais e quedas, que levam a fraturas do osso temporal ou lacerações da face e consequentemente lesões do nervo facial. A principal meta no estudo da regeneração nervosa é descobrir uma técnica adequada de reparo em lesões de nervos periféricos que traga como resultado a recuperação funcional das estruturas por eles inervadas. A sutura epineural é um método muito utilizado para recuperação de lesões nervosas, assim como o uso do adesivo de fibrina, que requer menor destreza do cirurgião. O adesivo derivado do veneno de serpente (CEVAP/UNESP, Botucatu-SP) é um selante biológico e biodegradável, pois não produz reações adversas, não contém sangue humano, apresenta uma boa capacidade adesiva, não transmite doenças infecciosas, e pode ser utilizado como coadjuvante em procedimentos de sutura convencional. Sendo assim, o objetivo deste trabalho foi comparar duas técnicas de recuperação de nervos periféricos lesionados: a sutura epineural término-terminal e o adesivo de fibrina derivado do veneno de serpente, e observar se o uso da laserterapia de baixa potência influencia esse processo de regeneração. Para isso, foram utilizados 42 ratos machos (Rattus norvegicus, Wistar), com 60 dias de vida, separados aleatoriamente em um Grupo Controle e quatro Grupos Experimentais, assim formados: Grupo Controle (GC, n=10), em que foi coletado o nervo facial íntegro aos 95 e 135 dias de vida; Grupo Experimental Sutura (GES, n=16) e Grupo Experimental Adesivo de Fibrina (GEF, n=16), onde no lado direito da face o ramo bucal do nervo facial foi seccionado e realizado a sutura epineural término-terminal e, no lado esquerdo da face, o ramo bucal do nervo facial foi seccionado e utilizado o adesivo de fibrina para coaptação das extremidades; Grupo Experimental Sutura e Laserterapia (GESL, n=16)...

The injuries involving peripheral nerves, especially facial traumatisms are very common and serious and longstanding facial paralysis lead to significant deterioration in the quality of the individuals life. The main goal in the study of nerve regeneration is finding a suitable repair technique for peripheral nerve injuries that bring results in the functional recovery of the structures innervated by them. Therefore, the aim of this study was to compare two techniques for recovery of injured peripheral nerves: the end-to-end epineural suture and fibrin adhesive derived from snake venom (CEVAP / UNESP, Botucatu-SP), and observeif the use of low-level laser therapy influences this regeneration process. For this purpose, 42 male rats (Rattus norvegicus, Wistar) were used , with 60 days of life, were randomly separated into a control group and four experimental groups, which were formed this way: Control Group (CG , n = 10), in which the intact facial nerve was collected at 95 and 135 days of life; Experimental Suture Group (ESG, n = 16 ) and Experimental Fibrin Adhesive Group (EFG, n = 16), where the right side of the face the buccal branch of the facial nerve was transectioned and the epineural end-to-end suture was performed and the left side of the face, the buccal branch of the facial nerve was transectioned and the fibrin glue was used for coaptation of the edges; Experimental Suture Laser Therapy Group (ESLG, n = 16) and Experimental Fibrin Adhesive Laser Therapy Group (EFLG, n = 16) underwent the same procedures of ESG and EFG , included the application of Laser Gallium- Aluminum-Arsenide (GaAlAs) by an 830 nm wavelength pulse continuous, 6 J/cm2, for 24 seconds, three times a week during five weeks at three points of the operated areas. The animals in the experimental groups were euthanized at 95 days (five weeks post-surgery) and 135 days (ten weeks post-surgery). The collected samples were...

Evaluation of nerve regeneration in diabetic rats

PURPOSE: To compare sciatic nerve regeneration between non-diabetic (control) and streptozotocin-induced diabetic Wistar rats. METHODS:Four subgroups were evaluated. CN: Non-diabetic rats submitted to neurorrhaphy (n=9); DN: Diabetic rats submitted to neurorrhaphy (n=9); CG: Non-diabetic rats submitted to nerve grafting (n=10); DG: Diabetic rats submitted to nerve grafting (n=9). The nerve regeneration was evaluated by walking track analysis (sciatic functional index), electrophysiological test, histomorphometric analysis and triceps surae muscle weight. RESULTS:At 60 days post-surgery, functional recovery of DN was similar to that of the non-diabetic rats (CN, CG), but DG didn't achieve the same. Evoked potential amplitudes showed no statistically significant differences among subgroups. Triceps surae muscle was heavier in CN. No statistically significant differences were observed between the control and diabetes subgroups with respect to histomorphometric analysis. CONCLUSION: After 60 days, DN had a functionally similar recovery to that of the control animals, whereas nerve grafting in diabetic rats didn't allow the same. The muscle atrophy was lower in CN. In the rest of evaluations, as electrophysiological and histomorphometric, diabetic rats were not different from control ones.

Peroneal nerve reconstruction by using glycerol-preserved veins: histological and functional assessment in rats

PURPOSE: To compare the degree of neural regeneration in rats upon interposition of autologous nerve graft, autogenous vein, glycerol-preserved autogenous vein, and glycerol-preserved allogeneic vein using qualitative and quantitative histological analyses as well as functional assessments. METHODS: Peroneal nerves were reconstructed differently in four groups of animals. Functional assessments were performed pre- and postoperatively for a period of six weeks. After six weeks, the animals were sacrificed and histological evaluations were performed. RESULTS: Histological patterns of autogenous veins without preservation showed pronounced neoangiogenesis and extensive axonal rarefaction, as confirmed by axonal counting and functional assessments. Glycerol-preserved veins had results similar to the control. CONCLUSIONS: Glycerol-preserved autogenous or allogeneic veins showed similar results to autograft results. The autogenous vein (without preservation in glycerol) presented histological and functional outcomes statistically lower than other groups.

Efeitos da laserterapia na regeneração nervosa periférica / Effects of laser therapy in peripheral nerve regeneration

OBJETIVO: Analisar o efeito do laser nas doses de 5, 10 e 20J/cm2 na reparação do nervo fibular de ratos após esmagamento. Os resultados foram avaliados por meio da análise funcional da marcha e de parâmetros morfométricos.MÉTODOS: Lesão por esmagamento controlado do nervo fibular comum direito e submetidos a intensidades crescentes (G1: sem irradiação; G2: sham; G3: 5J/cm2; G4: 10J/cm2; G5: 20J/cm2) de irradiação do laser diretamente sobre o local da lesão por 21 dias consecutivos. A análise funcional da marcha foi realizada a intervalos semanais, tendo sido medido o índice funcional do fibular (IFF). Os animais foram sacrificados nos 21º dia pós-operatório para remoção do nervo fibular, que foi preparado para a análise morfométrica.RESULTADOS: Não houve diferença significativa (p>0,05) dos valores da análise de marcha (IFF) entre os grupos em qualquer momento de avaliação para o parâmetro. A área total da secção transversal do nervo foi significantemente maior no grupo 2 do que nos grupos 3 e 4, enquanto a densidade de fibras foi significantemente maior no grupo 4 do que no demais grupos.CONCLUSÃO: A irradiação com o laser AsGaAl de baixa potência não acelerou a regeneração do nervo fibular com nenhuma das doses utilizadas. Nível de Evidência I, Estudos terapêuticos - Investigação dos Resultados do Tratamento.

OBJECTIVE: The influence of dose of low power lasertherapy (AsGaAl, 830 nm) on the regeneration of the fibular nerve of rats after a crush injury was evaluated by means of the functional gait analysis and histomorphometric parameters.METHODS: Controlled crush injury of the right common fibular nerve, immediately followed by increasing doses (G1: no irradiation; G2: simulated; G3: 5 J/cm2; G4: 10 J/cm2; G5: 20 J/cm2) laser irradiation directly on the lesion site for 21 consecutive days. Functional gait analysis was carried out at weekly intervals by measuring the peroneal/fibular functional index (PFI). The animals were killed on the 21st postoperative day for removal of the fibular nerve, which was prepared for the histomorphometric analysis.RESULTS: The PFI progressively increased during the observation period in all groups, without significant differences between them (p>0.05). The transverse nerve area was significantly wider in group 2 than in groups 3 and 4, while fiber density was significantly greater in group 4 than in all remaining groups.CONCLUSION: The low power AsGaAl laser irradiation did not accelerate nerve recovery with any of the doses used. Level of Evidence I, Therapeutic Studies Investigating the Results of Treatment.

Analysis of the expression of neurotrophins during regeneration of peripheral nerves in rats with vein graft / Análise da expressão de neurotrofinas durante a regeneração de nervo periférico de rato por enxerto venoso

Vein grafts have been employed to bridge the gap in transected peripheral nerves to produce better functional recovery. However several disadvantages such as secondary graft constriction were observed and a new alternative to this technique was developed by simply reversing the vein inside out. Both inside out and standard vein grafts were successfully used in recovering the sensory segmental defect in humans. Neurotrophins are a family of eurotrophic factors known to play an important role in the regeneration of peripheral nerves. The neurotrophin family consists of Nerve Growth Factor (NGF), Brain Derived Neurotrophic Factor (BDNF), Neurotrophin-3 (NT-3) and Neurotropinh-4 (NT-4). In the neurobiology field, several authors have been using PCR technique in order to gain more information regarding regenerated nerves. In this study, we employed this molecular biology technique to explore the role and level of the neurotrophins during the peripheral nerve regeneration with vein graft. The sciatic nerve of rats were sectioned and repaired with Inside out vein graft (IOVG) and standard vein graft techniques (SVG). In the control group the rats were sham operated wherein the sciatic nerve was kept intact. The animals were euthanized at 6 and 12 weeks and the grafts were harvested to observe the level the neurotrophins. EDL and Sol muscles were excised and measured to determine any weight difference between the groups. A small segment of the distal stumps from both the SVG and IOVG groups were also excised and were subjected to histological process to examine the amount of regenerated axon. In addition, another small segment of the distal stump was processed for RT-PCR to further examine the level of the neurotrophins in this area. At 6 weeks, no significant neuronal growth was observed in the distal stump of both graft types but a distinct growth was seen at 12 weeks. Walk track analysis showed poor motor function recovery ...

Análise da expressão de neurotrofinas durante a regeneração de nervo periférico de rato por enxerto venoso Enxertos de veias têm sido empregados para preencher lacunas em nervos periféricos transeccionados para melhor recuperação funcional. No entanto, vários inconvenientes, como a constrição do enxerto secundário foram observados. Uma nova alternativa para esta técnica foi desenvolvida. Simplesmente invertendo a veia de dentro para fora, chamado do Inside- out vein graft. As neurotrofinas são uma família de fatores neurotróficos conhecidos por desempenhar um papel significativo na regeneração de nervos periféricos. A família da neurotrofina é constituído por fator de crescimento nervoso (NGF), fator neurotrófico derivado do cérebro (BDNF), Neurotrofina-3 (NT-3) e Neurotrofina-4 (NT-4). No campo da neurobiologia, vários autores têm utilizado a técnica de PCR a fim de obter mais informações sobre os nervos regenerados. Neste estudo, foi utilizada a técnica de biologia molecular para explorar o papel e o nível das neurotrofinas durante a regeneração de nervos periféricos com enxerto de veia. O nervo isquiático de ratos foi seccionado e reparado com enxerto de veia invertida (IOVG) e técnicas de enxerto de veia padrão (SVG). No grupo controle, os ratos foram operados e o nervo isquiático foi mantido intacto. Os animais foram sacrificados após 6 e 12 semanas e os enxertos foram colhidos para observar o nível das neurotrofinas. Músculos EDL e Sóleo foram excisados e pesados para determinar a diferença de peso entre os grupos. Um pequeno segmento dos cotos distais de ambos os grupos SVG e IOVG também foram excisados e foram processados histologicamente para examinar a quantidade de axónios regenerados. Além disso, um outro pequeno segmento do coto distal foi processado para RT-PCR para analisar o nível das neurotrofinas nesta área.A tecnica do walk track analysis foi realizada para determinar o índice funcional do nervo isquiático nos grupos...