Partial regression of peripapillary myelinated nerve fibers after non-arteritic anterior ischemic optic neuropathy / Regressão parcial das fibras nervosas peripapilares mielinizadas após neuropatia óptica isquêmica anterior não arterítica

ABSTRACT A 71-year-old woman presented a non-arteritic anterior ischemic optic neuropathy in an optic nerve with previously registered superonasal peripapillary myelinated nerve fibers. Her past medical history was significant for controlled systemic hypertension, hyperlipidemia, and diabetes mellitus. The physiologic cup was absent in both optic discs. Non-arteritic anterior ischemic optic neuropathy mainly affected the temporal and inferior sectors of the peripapillary retinal nerve fiber layer, as could be demonstrated by retinal nerve fiber layer optical coherence tomography and optic disc optical coherence tomography angiography. Unlike other published reports, just a slight regression of the myelinated nerve fibers was observed after 1 year of follow-up. This occurred because ischemia mainly affected the temporal and inferior peripapillary sectors, whereas myelinated nerve fibers were superonasal to the optic disc.

RESUMO Uma mulher de 71 anos de idade apresentou neuropatia óptica isquêmica anterior não arterítica no nervo óptico com fibras nervosas peripapilares mielinizadas previamente registradas. Seu histórico médico foi significativo para hipertensão arterial sistêmica controlada, hiperlipidemia e diabetes mellitus. Em ambos os discos ópticos, a tacícula fisiológica esteve ausente. A neuropatia óptica isquêmica anterior não arterítica afetou principalmente os setores temporal e inferior da camada de fibras nervosas da retina peripapilar, como demonstrado pela tomografia de coerência óptica da camada de fibras nervosas da retina e pela angiotomografia de coerência óptica do disco óptico. Ao contrário de outros relatórios publicados, apenas uma ligeira regressão das fibras nervosas mielinizadas foi observada após um ano de acompanhamento. Isto pode ser explicado pelo fato da isquemia ter afetado principalmente os setores temporal e inferior peripapilares, enquanto as fibras nervosas de mielina eram nasal superior ao disco óptico.

Anatomical and ultrastructural sex differences in mean diameter and thickness of myelinated axons in adult rat corpus callosum / Diferencias sexuales anatómicas y ultraestructurales del diámetro medio y grosor de los axones mielinizados en el cuerpo calloso de ratas adultas

Sexual dimorphism exists at all levels of the nervous system. These sex differences could underlie genderrelated differences in behavior and neuropsychological function, as well as the gender differences in the prevalence of various mental disorders such as autism, attention deficit disorders, and schizophrenia. Myelination, on the other hand, is a unique cellular process that can have a dramatic impact on the structure and physiology of an axon and its surrounding tissue. The corpus callosum (CC) is the largest of the brain commissures, which connects the cerebral cortices of the two hemispheres, and provides interhemispheric connectivity for information transfer and processing between cortical regions. Variation in the axonal properties of CC will alter the interhemispheric connectivity. The CC consists of myelinated and unmyelinated axons, glial cells and blood vessels. Several functional studies have reported that the function of CC is associated with its axons density and myelination properties. The sexual dimorphism in the axonal content of the CC has always been controversial; hence, the aim of this study was to analyze the differences in axons' diameter and myelin sheath thickness of the CC between male and female rats. For this purpose, five pairs of adult male and female rats were perfused and the CC were removed and sectioned. Four sections from different subregions of the corpus callosum that represent the genu, anterior body, posterior body, and splenium of the CC were stained and electron microscopic images were captured using stereological guidelines. Later, the axons diameter and myelin sheath thickness for each subregion were calculated and compared between males and females. Our preliminary findings of the present study indicated region specific differences in the myelinated axon thickness and diameter in the CC between male and female rats.

El dimorfismo sexual existe en todos los niveles del sistema nervioso. Estas diferencias de sexo podrían ser la base de las diferencias de comportamiento y función neuropsicológica relacionadas con el sexo, así como las diferencias en la prevalencia de diversos trastornos mentales, como el autismo, los trastornos por déficit de atención y la esquizofrenia. La mielinización, por otro lado, es un proceso celular único que puede tener un impacto dramático en la estructura y fisiología de un axón y su tejido circundante. El cuerpo calloso (CC) es la mayor comisura cerebral, que conecta las cortezas cerebrales de ambos hemisferios, y proporciona la conectividad interhemisférica para la transferencia y el procesamiento de información entre regiones corticales. La variación en las propiedades axonales de CC alterará la conectividad interhemisférica. El CC consiste en axones mielinizados y no mielinizados, células gliales y vasos sanguíneos. Varios estudios funcionales han informado que la función de CC está asociada con la densidad de axones y las propiedades de mielinización. El dimorfismo sexual en el contenido axonal del CC siempre ha sido controvertido; por lo tanto, el objetivo de este estudio fue analizar las diferencias en el diámetro de los axones y el grosor de la vaina de mielina del CC entre ratas macho y hembra. Para este propósito, se perfundieron cinco pares de ratas macho y hembra adultas y se extrajeron y seccionaron las CC. Se tiñeron cuatro secciones de diferentes subregiones del cuerpo calloso que representan el genu, el cuerpo anterior, el cuerpo posterior y el esplenio y se capturaron imágenes de microscopía electrónicas utilizando referencias estereológicas. Posteriormente se calculó el diámetro de los axones y el grosor de la vaina de mielina para cada subregión y se compararon entre machos y hembras. Nuestros hallazgos preliminares del presente estudio indicaron diferencias específicas en el grosor y diámetro del axón mielinizado en el CC entre ratas macho y hembra.

Straatsma syndrome / Síndrome de Straatsma

Abstract The presence of retinal myelinated nerve fibers is not a rare finding during routine examinations, and it is usually a benign and isolated finding. However, in some rare cases, it can be associated with other ophthalmological conditions. We describe a case of a patient with the triad myelin nerve fibers, myopia and ambliopia, which configures the Straatsma Syndrome.

Resumo A presença de fibras de mielina é um achado comum durante exames oftalmológicos de rotina. Na maior parte das vezes, tem caráter beningno e é um achado isolado. No entanto, em alguns raros casos, a presença de mielinização pode estar associada a outras condições oftalmológicas. Descrevemos um caso de paciente com a tríade presença de fibras nervosas retinianas mielinizadas, miopia, e ambliopia, configurando a síndrome de Straatsma.

Foveosquisis miópica asociada al Síndrome de Straatsma / Myopic foveoschisis associated with Straatsma's syndrome

RESUMEN Este reporte describe la presentación concomitante de foveosquisis miópica y fibras de mielina en una paciente con miopía elevada. La primera puede ser un hallazgo incidental, pero no infrecuente en pacientes con miopía elevada, y causa pérdida visual central severa. La segunda es infrecuente, y en casos muy raros se presenta asociada a miopía ipsilateral y estrabismo. Ambas entidades deben incluirse en el diagnóstico diferencial de un paciente alto miope con disminución de la visión central. La tomografía de coherencia óptica es el medio auxiliar de elección(AU)

ABSTRACT This case report describes the concomitant presentation of myopic foveoschisis and myelinated retinal nerve fibers in a patient with elevated myopia. The myopic foveoschisis may be an incidental but not uncommon finding in highly myopic eyes, leading to severe central vision loss. Myelinated retinal nerve fibers are infrequent and in rarely cases they are associated with ipsilateral myopia and strabismus. Both entities should be including as differential diagnosis of central vision loss in high myopia, and optic coherence tomography is the leading as auxiliary test(AU)

Changes of white matter in LDLR knockout hypercholesterolemic rats / 国际脑血管病杂志

Objective To investigate the difference between histopathological changes of brain white matter in low-density lipoprotein receptor (LDLR) homozygous mutation rats with hypercholesterolemia and wild-type rats.Methods Thirty LDLR-/-rats and 28 wild-type rats were selected.Plasma cholesterol levels were measured by enzyme-linked immunosorbent assay at 15,18 and 26 weeks old respectively.The axonal structure of the corpus callosum area was observed by transmission electron microscopy.The myelin basic protein (MBP) of the corpus callosum area was quantitatively analyzed by Western blotting.In addition,at 26 weeks old,the myelin sheaths were stained by fast blue staining.The expression level of MBP in white matter was further detected by immunofluorescence staining,and the morphological changes of glial cells were observed.Results Compared with the wild-type rats,the plasma cholesterol concentration in LDLR-/-rats increased significantly,and it could be as high as 3.3 times at 26 weeks.The results of electron microscopy showed that the LDLR-/-rats had axonal injury at 15 weeks and aggravated gradually over time.At 26 weeks,Western blot analysis of the LDLR-/-rats showed that the MBP expression level of the corpus callosum area decreased significantly.Fast blue staining showed loosening of nerve fibers,diffuse vacuole formation,and myelinated nerve fiber loss in the corpus callosum area.In addition,it was also found that the number of oligodendrocytes in LDLR-/-rats was significantly reduced,and large numbers of astrocytes and microglia were activated.Conclusions LDLR-/-rats will have spontaneous hypercholesterolemia.Axonal injury,demyelination,decreased oligodendrocytes,as well as the abnormal activation of astrocytes and microglia are present in the early adult brain white matter area.

Straatsma syndrome: two case reports / Síndrome de Straatsma: dois relatos de caso

Abstract This article reports two cases of Straatsma Syndrome, a rare disease, emphasizing its clinical features that inclued myopia, strabismus and amblyopia associated with persistent myelinated fibers in the retina. Ophthalmic examination, color retinography and optical coherence tomography were performed.

Resumo Este artigo relata dois casos de síndrome de Straatsma, uma doença rara, enfatizando suas características clínicas que incluem miopia, estrabismo e ambliopia associada a persistência de fibras de mielina na retina. Foram realizados exame oftalmológico, retinografia e tomografia de coerência óptica.

Aspects of the macro and microscopic anatomy of the sciatic nerve in Wistar rats / Aspectos de la anatomía macro y microscópica del nervio ciático en ratas Wistar

The present study seeks to systematize morphological and morphometrical parameters and brings new data on the main branch of the lumbosacral plexus ­ i.e., sciatic nerve ­ in Wistar rats aged four and seven weeks. Sixteen female were divided into two groups, namely animals aged four weeks, and animals aged seven weeks. The specimens were studied at proximal and distal segments of the right hind limb sciatic nerves. Semi-thin transverse sections (0.25 µm thickness) were stained with 1 % toluidine blue, and the morphometric analysis was processed through the KS 400 software. Except for the number of fascicles and fascicular diameter, no differences were found between the proximal and distal segments. We observed differences when morphometric values were compared between 4- and 7- week old animals, with some exceptions (number of fascicles and myelinated fibers, and capillary area and number). The macroscopic data disagree with a previous description of the sciatic nerve being composed by two fascicles. Instead, sciatic nerve's only fascicle trifurcates or quadrifurcates at the distal third of the thigh. The total capillary area and density were calculated, and these are the first referential data for the sciatic nerve. Histograms of myelinated fiber and axons considering the animal ages were built. The results presented here are important because experimental studies, mainly studies on nerve regenerations require comparison with normal reliable data.

El objetivo fue sistematizar los parámetros morfológicos y morfométricos y traer nuevos datos sobre el ramo principal del plexo lumbosacro - es decir nervio ciático - en ratas Wistar de 4 a 7 semanas. Dieciséis ratas fueron divididas en dos grupos, con 4 y 7 semanas de edad. Las muestras estudiadas fueron los segmentos proximal y distal del nervio ciático derecho. Secciones delgadas (espesor 0,25 mm) fueron teñidas con azul de toluidina al 1 % y el análisis morfométrico se llevó a cabo utilizando el programa KS 400. Excepto para el número de fascículos y diámetro fascicular, no se encontraron diferencias entre los segmentos proximal y distal. Fueron observadas diferencias cuando se compararon los valores morfométricos entre animales de 4 y 7 semanas, con algunas excepciones (número de fascículos y fibras mielinizadas, área y número de capilares). Los datos macroscópicos no están de acuerdo con la descripción anterior del nervio ciático siendo compuesto por dos fascículos. En cambio, sólo trifurcación o cuadrifurcación fueron encontrados en el tercio distal del muslo. El área total capilar y la densidad fueron calculadas y estos constituyen los primeros datos de referencia para el nervio ciático. Se construyeron histogramas de fibras mielínicas y axones, teniendo en cuenta las edades de los animales. Los resultados presentados aquí son importantes porque los estudios experimentales, en especial aquellos sobre la regeneración nerviosa, requieren comparación con datos confiables normales.

Sindrome Straatsma asociado a agujero macular lamelara / Straatsma syndrome asociated with macular lamellar hole

Objetivo: Describir el caso clínico de una paciente con síndrome de Straatsma asociado con agujero macular lamelar. Métodos: Reporte de caso. Resultados: Reportamos un caso de una paciente de 17 años de edad con hallazgos de mielinización de capa de fibras nerviosas en el ojo izquierdo, asociado a miopía y ambliopía, lo cual conforma el síndrome de Straatsma. Además, la paciente presenta agujero macular lamelar, una rara asociación con este síndrome. Conclusión: El síndrome de Straatsma es una patología rara, caracterizada por la presencia de mielinizacion de capa de fibras nerviosas, miopía y ambliopía; el cual puede estar asociado a otro tipo de complicaciones retinianas como oclusiones vasculares, membranas epirretinianas, agujeros maculares de espesor total y lamelares, las cuales pueden llevar a empeoramiento de la visión.

Objective: To describe the clinical case of a patient with Straatsma syndrome associated with a macular lamellar hole. Methods: Case report. Results: We report a case of a 17-year-old female patient with findings of myelinization retinal nerve fibers in the left eye, associated with myopia and amblyopia, which forms the Straatsma syndrome. In addition, the patient has a macular lamellar hole, a rare association with this syndrome. Conclusion: Straatsma syndrome is a rare pathology, characterized by the presence of myelinization of nerve fiber layer, myopia and amblyopia; which may be associated with other types of retinal complications such as vascular occlusions, epiretinal membranes, macular and lamellar holes, which can lead to worsening of vision.

Hind limb sensory innervation in rats: comparison between sural and saphenous nerve morphometry / Inervación sensorial de los miembros posteriores en ratas: comparación morfométrica entre los nervios sural y safeno

Although numerous studies investigate sensory recovery of the hind paw of the rat after nerve damage, still no comprehensive overview of its normal innervation is present in the literature. We investigated the morphometry of myelinated fibers in the sural and saphenous nerves and analyzed their size distributions in young rats. Six 30-day-old female Wistar rats were perfused with 2.5% glutaraldehyde and their right and left sural and saphenous nerves were prepared for light microscopy and morphometry. Morphometric data were compared between segments (proximal versus distal) and sides (right versus left) for the same nerves. Also, segments from right or left sides were compared between nerves (sural versus saphenous). Both, the sural and saphenous nerves, exhibited proximal to distal symmetry on both sides as well as left-right symmetry. Histograms of the diameter of the myelinated fibers were unimodal in both nerves, regardless of segments or sides with the peaks of the fibers size occurring between 2.5 and 4.0 µm. The axon distributions reflected the myelinated fiber distributions, with the sural and saphenous nerves peaking between 1.5 and 2.0 µm. The G ratio (the ratio between the axon and fiber diameters) distributions were also unimodal, with peaks at 0.6 for both nerves. This study contributes to the literature with information on the myelinated fibers morphometry from the two sensory nerves responsible for the rat hind limb innervation. This information is valuable for a better understanding of the possible contribution of collateral sprouting from the sural or saphenous nerves on the paw sensory territory recovery observed after one of these nerves is damaged.

Aunque numerosos estudios investigan la recuperación sensorial del miembro pélvico o posterior de la rata después del daño en los nervios, aún no existe en la literatura una visión global de su inervación normal. Investigamos la morfometría de fibras mielínicas de los nervios sural y safeno y analizamos sus distribuciones de tamaño en ratas jóvenes. Seis ratas Wistar de 30 días de edad fueron perfundidas con 2,5% de glutaraldehído, se prepararon los nervios sural y safeno derecho e izquierdo para microscopía de luz y morfometría. Datos morfométricos fueron comparados entre los segmentos (proximal vs distal) y laterales (derecho vs izquierdo) para los mismos nervios. Además, los segmentos de los lados derecho e izquierdo se compararon entre los nervios (sural vs safeno). Ambos nervios sural y safeno exhibieron una simetría proximal a distal en ambos lados, así como una simetría izquierda-derecha. Histogramas del diámetro de las fibras mielinizadas eran unimodales en ambos nervios, independientemente de los segmentos o de los lados, siendo los peaks del tamaño de las fibras entre 2,5 y 4,0 micras. Las distribuciones de los axones reflejan las distribuciones de fibras mielinizadas, de los nervios sural y safeno que alcanzaban entre 1,5 and 2,0 µm. La relación de G (relación entre los diámetros de los axones y de fibra) eran también unimodales, alcanzando 0,6 para ambos nervios. Este estudio contribuye a la literatura con los datos de la morfometría de fibras mielinizadas de ambos nervios sensoriales responsables de la inervación de la extremidad pélvica de la rata. Esta información es valiosa para una mejor comprensión de los nervios sural y safeno en la recuperación sensorial del miembro después de que uno de estos nervios ha sido dañado.

Synthetic biodegradable nerve conduits for repair of injured peripheral nerve:good biocompatibility / 中国组织工程研究

BACKGROUND:In the treatment of peripheral nerve injury, we can use autologous nerve or the nerve conduit of different materials. OBJECTIVE:To explore the effects of biodegradable nerve conduit in repairing peripheral nerve injury. METHODS:A total of 48 New Zealand white rabbits were randomly divided into autologous nerve graft group, silicone catheter group and biodegradable nerve conduit group. 10-mm sciatic nerve was obtained from each group to construct animal models of sciatic nerve defect, which was repaired with autologous nerve, silicone catheter and biodegradable nerve conduit. RESULTS AND CONCLUSION:At 3 weeks after transplantation, motor nerve conduction and recovery rate of triceps muscle wet weight were poorer in the silicone catheter group than in the autologous nerve graft group. Motor nerve conduction and recovery rate of triceps muscle wet weight were similar between the biodegradable nerve conduit group and autologous nerve graft group. At 12 weeks, a large number of uniform myelinated nerve fiber was visible in the autologous nerve graft group. A large number of uneven myelinated nerve fiber was found in the biodegradable nerve conduit group. A smal number of uneven myelinated nerve fiber was seen in the silicone catheter group. These data suggest that the synthetic biodegradable materials of nerve conduit can obtain good effect, which is close to the autologous nerve graft.

The brain functional magnetic resonance imaging characteristics induced by contact heat stimulations in normal adults / 中华神经科杂志

Objective Aδ and C fiber nociceptors can be excited when people received contact heat stimulation(CHS) and this excitation may be reflected by functional magnetic resonance imaging(fMRI).The aim of this study was to observe the different fMRI characteristics in CHS with distinct temperatures in healthy people and to explore the pain related functional network.Depending on the fMRI results,we can evaluate the values of CHS-fMRI during the research of brain functional connectivity.Methods Twenty-two healthy volunteers were recruited to this study.During the acquisition of fMRI,the right dorsal forearm received two different CHS in 41 and 51 degree respectively(41 ℃ CHS-fMRI group and 51 ℃ CHS-fMRI group),and two series of fMRI data were obtained for each subject.The brain activation was obtained by using one sample t test for the 41 ℃CHS-fMRI group and 51 ℃CHS-fMRI group separately.The difference between 41 ℃ CHS-fMRI group and 51 ℃ CHS-fMRI group was analyzed by paired-sample t-test.Result These activated brain areas in 41 ℃ CHS-fMRI group included bilateral superior temporal gyrus (STG),contralateral transverse temporal gyrus,contralateral amygdala,bilateral insula,bilateral inferior frontal gyrus (IFG),contralateral hippocampus,bilateral putamen,contralateral supramarginal,ipsilateral postcentral,ipsilateral inferior parietal lobule,ipsilateral middle temporal gyrus (MTG),bilateral cerebelum,bilateral middle cingulate cortex and bilateral posterior cingulate cortex.These activated brain areas in 51 ℃ CHS-fMRI group included bilateral STG,bilateral amygdala,contralateral hippocampus,bilateral thalamus,contralateral putamen,bilateral insula,bilateral IFG,bilateral cerebellum,contralateral postcentral,contralateral superior parietal lobule,bilateral MTG,bilateral precuneus,and contralateral cuneus.Compared with 41 ℃ CHS-fMRI group,the 51 ℃ CHS-fMRI group showed higher brain activation in bilateral cerebellum (right:4.455,left:3.891),ipsilateral precuneus (4.150),contralateral insula (3.530),contralateral IFG (3.530),and contralateral postcentral (3.530; t =2.83,P ＜ 0.01).Conclusions There are common brain activated areas and specific areas for each group,which suggested that existence of two central pathways activated by Aδ and C fiber which have different effects in perception of pain and have their brain network responsively.It may become one of the ideal pain stimulation methods with CHS-fMRI,which warrant worth further research.

The analysis of the clinical and pathologic features in patients with peripheral neuropathy as main manifestation of microscopic polyangiitis / 中华神经科杂志

Objective To investigate the clinical and pathologic features in patients of microscopic polyangiitis (MPA) with peripheral nerve abnormality.Methods We collected clinical data of 6 patients with MPA that was confirmed by immunological,pathological and clinical findings.Electroneurophysiologic examinations and sural nerve biopsies were performed in these patients.Two normal controls were included in these studies.Results All of 6 patients developed asymmetric polyneuropathies.Electrodiagnostic studies showed reduced amplitudes of the sensory nerve action potential and compound motor action potential with mild impaired conductive velocities.The patients presented vasculitis changes with cell infiltration by monocytes and lymphocytes.Sural nerve biopsies found loss of myelinated fibers in all of the patients indicating axonal degeneration.Some of them associated with regeneration clusters of myelinated fibers.Conclusions Asymmetric neuropathy with sensory nerve injuries is the mainfeature in the MPA associated polyneuropathy.Electrodiagnostic examination indicated axonal lesions in mononeuritis multiplex.Sural nerve biopsies confirmed the active axonal lesions and vasculitis.

Electrophysiological abnormalities associated with extensive myelinated retinal nerve fibers.

An observational case report of electrophysiological abnormalities in a patient with anisomyopic amblyopia as a result of unilateral extensive myelinated retinal nerve fibers (MNFs) is illustrated. The electrophysiological readings revealed an abnormal pattern electroretinogram (PERG) but normal full-field electroretinogram readings in the affected eye. The visual-evoked potential was also undetectable in that eye. Our findings suggest that extensive MNFs can be associated with electrophysiological abnormalities, in particular the PERG, which can aid in diagnosing the cause of impaired vision when associated with amblyopia.

Transmission electron microscopy studies of the vestibulocochlear nerve in chronic diabetic rats / Estudios de microscopía electrónica de transmisión del nervio vestibulococlear en ratas diabéticas crónicas

It is widely described in the literature that diabetic patients present hearing impairment. Despite the histological alterations of the internal ear structures in these patients as well as in experimental models of diabetes, to the best of our knowledge, an histological evaluation of the vestibulocochlear nerve have not been performed. In the present study, ultrastructural alterations are described and compared between a spinal nerves and a cranial nerve in rats with chronic induced diabetes. Male Wistar rats (n = 12), fed with standard diet from the animal care facility at 42 days of age were used. Induced diabetic animals (n=6) were fasted for 12 hours prior to being injected intraperitoneally with streptozotocin (STZ - 60mg/kg) in a single dose. Control animals (n=6) received (0.01 mol/l citrate buffer, pH 4.5) vehicle alone. Ten weeks after STZ injection the animals were perfused intracardially with Karnovsky solution. Right and left vestibulocochlear nerves were dissected and histologically processed for epoxy resin embedding. Samples were imaged with the transmission electron microscope. Large myelinated fibers with morphological signs of axonal atrophy in the vestibulocochlear nerves were readily observed. These results suggest that chronic STZ-induced diabetes in rats caused alterations in the myelinated fibers and Schwann cells, compatible to the classic diabetes signs and symptoms. Morphological alterations of the vestibulocochlear nerve in diabetes is described for the first time and contributes information for a better understanding of why there are changes in hearing observed in diabetic patients.

Se ha descrito ampliamente en la literatura que los pacientes diabéticos presentan discapacidad auditiva. En estos pacientes, a pesar de las alteraciones histológicas de las estructuras del oído interno, así como en modelos experimentales de diabetes, que mejoran nuestro conocimiento, la evaluación histológica del nervio vestibulococlear no ha sido realizada. Se describen y comparan las alteraciones ultraestructurales entre un nervio espinal y uno craneal en ratas con diabetes crónica inducida. Fueron utilizadas 12 ratas Wistar machos, de 42 días de edad, alimentadas con dieta estándar. Los animales diabéticos inducidos (n = 6) se mantuvieron en ayuno por 12 horas antes de ser inyectados por vía intraperitoneal con estreptozotocina (STZ - 60mg/kg) en una sola dosis. Los animales control (n = 6) sólo recibieron inyección de 0.01 mol/l buffer, citrato pH 4,5. Diez semanas después de la inyección de STZ, los animales fueron perfundidos intracardiacamente con solución de Karnovsky. Los nervios vestibulococlear derecho e izquierdo fueron disecados y procesados histológicamente para ser incluidos en resina epoxy. Las muestras fueron estudiadas con microscopio electrónico de transmisión. Fueron observadas fácilmente, grandes fibras mielinizadas con signos morfológicos de atrofia axonal en los nervios vestibulococlear. Estos resultados sugieren que la diabetes crónica inducida por STZ en ratas causó alteraciones en las fibras mielínicas y células del neurilema, compatible, con los signos y síntomas clásicos de la diabetes. Alteraciones morfológicas del nervio vestibulococlear en la diabetes son descritas por primera vez, lo que aporta información para una mejor comprensión de por qué hay cambios en la audición en los pacientes diabéticos.

Demyelination of neurofilament protein 200 immune positive never fibers in human pulp

INTRODUCTION: Mammalian tooth pulp is densely innervated by sensory nerves that are mostly C fibers and A delta fibers. However, there is evidence suggesting that many unmyelinated axons in the pulp are in fact parent meylinated axons. MATERIALS AND METHODS: The pulp was removed from healthy premolars and 3rd molars extracted from juveniles and adults undergoing orthodontic treatment, and immunohistochemical staining were applied with NPF200 antibodies, which specifically dye myelinated axons. The specimens underwent an electron microscopy examination with diaminobenzidine (DAB) immunostaining after observation and analysis by fluorescence and confocal laser scanning microscopy. RESULTS: The NPF200 immuno-positive axons in the radicular pulp areas were observed as bundles of many nerve fibers. Many small bundles were formed with fewer axons when firing to the coronal pulp areas and then reachrd a different direction. CONCLUSION: Myelinated fibers innervated to the dental pulp maintain their myelins in the radicular portion, but these fibers lost myelins in the coronal portion. Afterthe loss of myelin, the size of the axoplasm also decreased.

Effects of running exercise on the hippocapal formation and the myelinated nerve fibers in the hippocampal formation of mid-aged rats / 解剖学报

ObjectiveTo investigate the effects of exercise on the hippocampal formation and the myelinated nerve fibers in the hippocampal formation of middle-aged rats. MethodsTen 14-month female SD rats were randomly divided into exercise group and sedentary group.Rats in the exercise group were forced to run on a treadmill for 4 months. After 4 months, spatial learning capacity of two group rats was tested using the Morris water maze.Then, the hippocampal formation and the myelinated nerve fibers in the hippocampal formation were quantitatively estimated using transmission electronic microscopy and stereological techniques. Results Treadmill running enhanced the spatial learning capacity of the rats. The volume of hippocampal formation and the total length of the myelinated nerve fibers in the hippocampal formation were significantly increased after 4 months exercise.However,there was no significant difference in the total volume of the myelinated fibers in the hippocampal formation between the two groups.The absolute distributions of the total length of the myelinated fibers in the hippocampal formation of two groups indicated that the exercise-induced increase of the total length of the myelinated nerve fibers in the hippocampal formation was mainly due to the increase of the myelinated fibers with small diameter. Conclusions Four months running exercise remarkably influence the spatial learning capacity,hippocampal formation and the myelinated fibers in the hippocampal formation of the middle-aged famale SD rats. The present results reveal a potential mechanism for the fact that exercise might improve brain function.

Short-term enriched environment increases the total length of the myelinated nerve fibers in the hippocampal formation of mid-aged male rats / 解剖学报

ObjectiveTo investigate the effects of short-term enriched environment on the hippocampal formation and the myelinated fibers in the hippocampal formation of mid-aged male rats. MethodsTwenty 14-month old male SD rats were randomly divided into enriched group and standard group. Enriched rats were reared in enriched environment and standard rats were reared in standard environment for 4 months. Then, the spatial learning capacity of enriched rats and standard rats was tested with the Morris water maze. After the Morris water maze test, the total volume of the hippocampal formation and the myelinated nerve fibers in the hippocampal formation were quantitatively estimated with transmission electronic microscopy technique and stereological methods. Results There was not significant difference in the spatial learning capacity between enriched group and standard group. The total volume of the hippocampal formation of enriched rats was not significantly increased by 4.6% when compared with that of standard rats. The total volume, total length and mean diameter of the myelinated nerve fibers in the hippocampal formation of enriched rats were significantly increased when compared with those of standard rats. Conclusions Four-months enriched environment significantly affected the myelinated fibers in the hippocampal formation of mid-aged male SD rats. The present results might provide an important theoretical basis for searching the ethology strategy to delay the progress of brain aging in the future.

Effects of short-term enriched environment on the hippocampal formation and the myelinated fibers in the hippocampal formation of mid-aged female rats / 解剖学报

ObjectiveTo investigate the effects of short-term enriched environment on the hippocampal formation and the myelinated fibers in the hippocampal formation of mid-aged female rats. Methods Twenty 14-month female SD rats were randomly divided into 10 enriched environment (EE) rats and 10 standard environment (SE) rats. EE rats were reared in enriched environment and SE rats were reared in standard environment for 4 months. Then, five rats were randomly selected from each group. The spatial learning capacity was assessed with Morris water maze. The hippocampal formation and the myelinated fibers in the rat hippocampal formation were quantitatively investigated with transmission electronic microscopy technique and stereological methods. Results Short-term enriched environment enhanced the spatial learning capacity of the mid-aged female rats. The total length and total volume of the myelinated fibers in the hippocampal formation of the EE rats was significantly increased by 43.3% and 47.4%, respectively, when compared to the SE rats. There was no significant difference in the hippocampal volume and the mean diameter of the myelinated fibers in the hippocampal formation between two groups. The increase of the total length of the myelinated nerve fibers in the hippocampal formation was mainly due to the increase of the myelinated fibers with small diameter. Conclusion Short-term enriched environment had significant effects on the spatial learning capacity and the myelinated fibers in the hippocampal formation of middle-aged female rats.

Stereological study of the age-related changes of the myelinated nerve fibers in the hippocampal formation of rat / 解剖学报

Objective To explore the changes of the hippocampal formation and the myelinated nerve fibers in the hippocampal formation of aged female Long-Evans rat. Methods The hippocampal formation and the myelinated nerve fibers in the hippocampal formation of 5 young (6-month old), 5 middle-aged (18-month old) and 6 aged (28-month old) female Long-Evans rats were quantitatively investigated with the stereological techniques and transmission electronic microscope technique. Results There were no significant changes in the volume of hippocampal formation, the volume density, the total volume, the length density and the mean diameter of the myelinated nerve fibers in the hippocampal formation among young, middle-aged and aged rats. When compared to that of young rats, the total length of the myelinated nerve fibers in the hippocampal formation of middle-aged rats was significantly increased by 63.6%. When compared to that of middle-aged rats, the total length of the myelinated nerve fibers in the hippocampal formation of aged rats was significantly decreased by 47.5%. When compared to that of young rats, the total length of the myelinated nerve fibers in the hippocampal formation of aged rats was non-significantly decreased by 13.8%. Conclusion Although the reason why the total length of the myelinated nerve fibers in the hippocampal formation of middle-aged rats was longer than that of young rats needs further investigations, the present results together with our previous findings in white matter and cortex further suggest that there are age-related changes of the myelinated nerve fibers in the normal aged brains.

The Effects of Soybean Diet on the Diabetic Neuropathy in the Rats / 대한해부학회지

Neuropathy is a serious and disabling complication that contributes to increased morbidity and mortality in diabetic patients. There is progressive distal to proximal axonal atrophy that ultimately leads to Wallerian degeneration. This study was performed to identify the effect of soy bean on diabetic neuropathy using morphometry. Male Sprague-Dawley rats were grouped into control, diabetic with red chow diet and diabetic with soy bean diet. The myelinated nerve fibers were counted and fiber size distributions were evaluated in each group at 4 and 8 weeks, respectively. Diabetic neuropathy didn't develop in streptozotocin-induced diabetic rats at four weeks. At 8 weeks, the myelinated nerve fiber in diabetic with soy bean diet was larger in number than that in diabetic to which did not be administered insulin. The number of myelinated nerve fiber was not different between diabetic group with insulin and without insulin. Mean myelinated nerve fiber size was smaller in diabetic with soy bean diet than diabetic with red chow diet and control. Histogram of fiber size distribution was shifted to left in diabetic with red chow and soy bean diet groups compared to control. Light and electron microscopic findings showed marked degeneration of nerve fibers in diabetic with red chow diet but preservation in diabetic with soy bean diet. The level of glucose and HbA1c was lower in diabetic with soy bean diet than red chow diet. Soy bean could be effective in the protection of neuropathy induced by diabetes mellitus.