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BACKGROUND: Contextual fear conditioning (CFC) is a rodent model that induces a high and long-lasting level of conditioning associated with traumatic memory formation; this behavioral paradigm resembles many characteristics of posttraumatic stress disorder (PSTD). Chemokines (chemotactic cytokines) play a known role in neuronal migration and neurodegeneration but their role in cognition is not totally elucidated. AIM: We ascertain whether CCR5/RANTES beta chemokines (hippocampus/prefrontal cortex) could play a role in fear memory consolidation (CFC paradigm). We also evaluated whether chronic stress restraint (21 days of restraint, 6-h/day) could regulate levels of these beta chemokines in CFC-trained rats; fear memory retention was determined taking the level of freezing (context and tone) by the animals as an index of fear memory consolidation 24 h after CFC training session; these chemokines (CCR5/RANTES) and IL-6 levels were measured in the hippocampus and prefrontal cortex of chronically stressed rats, 24 h after CFC post-training, and compared with undisturbed CFC-trained rats (Experiment 1). In Experiment 2, rats received 1 mA of footshock during the CFC training session and fear memory consolidation was evaluated at 12 and 24 h after CFC training sessions. We evaluated whether RANTES levels could be differentially regulated at 12 and 24 h after CFC training; in Experiment 3, maraviroc was administered to rats (i.m: 100 mg/Kg, a CCR5 antagonist) before CFC training. These rats were not subjected to chronic stress restraint. We evaluated whether CCR5 blockade before CFC training could increase corticosterone, RANTES, or IL-6 levels and affects fear memory consolidation in the rats 24-h post-testing compared with vehicle CFC-trained rats. RESULTS: Elevations of CCR5/RANTES chemokine levels in the hippocampus could have contributed to fear memory consolidation (24 h post-training) and chronic stress restraint did not affect these chemokines in the hippocampus; there were no significant differences in CCR5/RANTES levels between stressed and control rats in the prefrontal cortex (Experiment 1). In Experiment 2, hippocampal CCR5/RANTES levels increased and enhanced fear memory consolidation was observed 12 and 24 h after CFC training sessions with 1 mA of footshock. Increased corticosterone and CCR5/RANTES levels, as well as a higher freezing percentage to the context, were found at 24 h CFC post-testing in maraviroc-treated rats as compared to vehicle-treated animals (experiment-3). Conversely, IL-6 is not affected by maraviroc treatment in CFC training. CONCLUSION: Our findings suggest a role for a hippocampal CCR5/RANTES axis in contextual fear memory consolidation; in fact, RANTES levels increased at 12 and 24 h after CFC training. When CCR5 was blocked by maraviroc before CFC training, RANTES (hippocampus), corticosterone levels, and fear memory consolidation were greater than in vehicle CFC-trained rats 24 h after the CFC session.
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Corticosterona/sangre , Hipocampo/metabolismo , Maraviroc/farmacología , Consolidación de la Memoria , Trastornos por Estrés Postraumático/metabolismo , Corticoesteroides/sangre , Corticoesteroides/metabolismo , Animales , Antagonistas de los Receptores CCR5/farmacología , Quimiocina CCL5/metabolismo , Modelos Animales de Enfermedad , Miedo/efectos de los fármacos , Inmunomodulación , Interleucina-6/metabolismo , Masculino , Memoria/efectos de los fármacos , Plasticidad Neuronal , Corteza Prefrontal/metabolismo , Ratas , Ratas Wistar , Receptores CCR5/metabolismo , Estrés MecánicoRESUMEN
Antecedentes: El alcohol es considerada una droga que tiene repercusión negativa en la vida del individuo consumidor activo o no. El consumo de alcohol es multifactorial y preocupa en jóvenes universitarios por ser una droga de fácil acceso, barato y con menos estigma a nivel social. Objetivo: Des-cribir y comparar el consumo de alcohol en estudiantes de medicina hombres y mujeres que cursan las asignaturas de Farmacología I y II el primer semestre del año 2017 en la Escuela Universitaria de Ciencias de la Salud en la Universidad Nacional Autonoma de Honduras en el Valle de Sula (EUCS/ UNAH-VS). Pacientes y métodos: Estudio cuantitativo, alcance descriptivo. Población: muestra por conveniencia de 56 estudiantes (28 mujeres y 28 hombres). Se utilizó un instrumento tipo cuestionario para la recolec-ción de datos, previo consentimiento infor-mado. Resultados: El 73%. (41) consumía alcohol. Los resultados revelaron mayor con-sumo en mujeres 43% (24) que en hombres 30% (17). Un 36.7% (20) refiere la ingesta de alcohol en vacaciones y 26.8% (15) después de exámenes. Un 98% (55) conocían de los efectos nocivos del alcohol. Conclusiones:El consumo de alcohol es una práctica en los jóvenes universitarios de las asignaturas de Farmacología I y II. Un alto porcentaje de los estudiantes partícipes de éste estudio ha consumido alcohol, la mayoría lo hace oca-sionalmente. El consumo es mayor por parte de las mujeres. La sustancia más consumida es la cerveza (ambos sexos). La mayoría conoce los efectos nocivos del alcohol, pero no los detiene a consumirlo...(AU)
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Humanos , Masculino , Femenino , Estudiantes de Farmacia , Consumo de Bebidas Alcohólicas , Alcoholismo/complicacionesRESUMEN
En el sistema nervioso central de los mamíferos, las células gliales superan diez veces en número a las neuronas. Su número permanente estacionario durante la edad adulta, controlado por la presencia simultánea de mitógenos gliales e inhibidores de esos mitógenos. El inhibidor más abundante, la neurostatina, es el gangliósido GD1b O-acetilado en el grupo 9 del ácido siálico más externo. La neurostatina y los oligosacáridos sintéticos inhiben la proliferación de astroblastos en cultivo primario (citostáticos) y de células de gliomas (citotóxicos), tanto de roedores como de humanos, en concentración nanomolar. A esas concentraciones, la neurostatina no tuvo efecto sobre células de linaje no glial ni sobre glía madura. La neurostatina y sus análogos mostraron actividad antimitótica directa sobre las células tumorales, interfiriendo con la progresión del ciclo celular en múltiples sitios, pero también actuaron indirectamente, haciendo visibles las células tumorales al sistema inmune del huésped y activando linfocitos CD4+ y CD8+. Análogos de neurostatina podrían generar nuevos fármacos antiinflamatorios, con múltiples acciones directas e indirectas contra el crecimiento de gliomas, una patología todavía sin tratamiento clínico satisfactorio. La neurostatina es producida por las neuronas, pero el contacto de éstas con astrocitos estimula notablemente su expresión. La acción de la neurostatina puede estar mediada por numerosas proteínas receptoras, incluyendo integrinas, siglecs y receptores Toll-like (AU)
Glial cells in the central nervous system of adult mammals outnumber neurons 10-fold. Their number remains stationary throughout adulthood, controlled by the concomitant presence of mitogens and mitogen inhibitors. The most abundant inhibitor, neurostatin, is ganglioside GD1b O-acetylated on hydroxyl 9 of its outermost sialic acid. Neurostatin inhibited the proliferation of primary microglia and astroblasts in culture (cytostatic) as well as both rodent and human glioma cells (cytotoxic) at nanomolar concentrations. At those concentrations neurostatin had no effect on non-glial lineage cells or differentiated glia. Neurostatin shows direct antimitotic activity on tumoral cells, interfering with multiple signals regulating cell cycle progression. But it also promotes indirectly total destruction of experimental rat brain glioma, presumably by making it visible to the host immune system and activating CD4+ and CD8+ lymphocytes. Neurostatin could be a new anti-inflammatory agent, with multiple convergent direct and indirect actions on glioma growth, a pathology without satisfactory clinical treatment. Neurostatin is produced by neurons but its expression is up-regulated by neuron-astrocyte contact. The action of neurostatin could be mediated by a number of receptor proteins, including integrins, Toll-like receptors and siglecs (AU)
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Humanos , Glucolípidos/farmacocinética , Neuronas/fisiología , Células Ependimogliales/fisiología , Neuroglía/fisiología , Lesiones Traumáticas del Encéfalo/fisiopatología , División Celular/fisiología , Mitógenos/fisiología , Gangliósidos/fisiología , Receptores Toll-Like/fisiologíaRESUMEN
Microglia and astrocytes are the major source of cytokines in Alzheimer,s disease (AD). CX3CR1 is a delta chemokine receptor found in microglia and its neuronal ligand, Fractalkine, has two isoforms: an anchored-membrane isoform, and a soluble isoform. The reduced soluble fractalkine levels found in the brain (cortex/hippocampus) of aged rats, may be a consequence of neuronal loss. This soluble fractalkine maintains microglia in an appropiate state by interacting with CX3CR1. The ablation of the CX3CR1 gene in mice overexpressing human amyloid precursor protein (APP/PS-1) increased cytokine levels, enhanced Tau pathology and worsened behavioural performance in these mice. However, CX3CR1 deficiency resulted in a gene dose-dependent Aß clearance in the brain, and induced microglial activation. In addition, CX3CR1 deficiency can have benefical effects by preventing neuronal loss in the 3xTg model. In fact, CX3CR1 deficiency increases microglial phagocytosome activity by inducing selective protofibrillar amyloid-beta phagocytosis in microglial cells in transgenic AD models. On the other hand, the fractalkine membrane isoform plays a differential role in amyloid beta clearance and Tau deposition. This anchored membrane FKN signalling might increase amyloid pathology while soluble fractalkine levels could prevent taupathies. However, in human AD, the only published study has reported higher systemic fractalkine levels in AD patients with cognitive impairment. In mouse models, inflammatory activation of microglia accelerates Tau pathology. Studies in transgenic mice with fractalkine null mice suggest that APP/PS-1 mice deficient for the anchored membrane-fractalkine isoform exhibited enhanced neuronal MAPT phosphorylation despite their reduced amyloid burden. The soluble fractalkine overexpression with adenoviral vectors reduced tau pathology and prevented neurodegeneration in a Tg4510 model of taupathy Finally, animals with Aß (1-42) infused by lentivirus (cortex) or mice with the P301L mutation (frontotemporal dementia) had caspase-3 activation (8-fold) and higher proinflammatory TNF alpha levels and p-Tau deposits at 4 weeks postinfusion. Thus, the CX3CR1/Fractalkine axis regulates microglial activation, the clearance of amyloid plaque and plays a role in p-Tau intraneuronal accumulation in rodent models of AD.
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Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Quimiocina CX3CL1/metabolismo , Proteínas tau/metabolismo , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Péptidos beta-Amiloides/genética , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Biomarcadores/metabolismo , Quimiocina CX3CL1/genética , Citocinas/metabolismo , Modelos Animales de Enfermedad , Humanos , Ratones , Ratones Transgénicos , Microglía/metabolismo , Ratas , Proteínas tau/genéticaRESUMEN
The increased risk and prevalence of lacunar stroke and Parkinson's disease (PD) makes the search for better experimental models an important requirement for translational research. In this study we assess ischemic damage of the nigrostriatal pathway in a model of lacunar stroke evoked by damaging the perforating arteries in the territory of the substantia nigra (SN) of the rat after stereotaxic administration of endothelin-1 (ET-1), a potent vasoconstrictor peptide. We hypothesized that transplantation of neural stem cells (NSCs) with the capacity of differentiating into diverse cell types such as neurons and glia, but with limited proliferation potential, would constitute an alternative and/or adjuvant therapy for lacunar stroke. These cells showed neuritogenic activity in vitro and a high potential for neural differentiation. Light and electron microscopy immunocytochemistry was used to characterize GFP-positive neurons derived from the transplants. 48 h after ET-1 injection, we characterized an area of selective degeneration of dopaminergic neurons within the nigrostriatal pathway characterized with tissue necrosis and glial scar formation, with subsequent behavioral signs of Parkinsonism. Light microscopy showed that grafted cells within the striatal infarction zone differentiated with a high yield into mature glial cells (GFAP-positive) and neuron types present in the normal striatum. Electron microscopy revealed that NSCs-derived neurons integrated into the host circuitry establishing synaptic contacts, mostly of the asymmetric type. Astrocytes were closely associated with normal small-sized blood vessels in the area of infarct, suggesting a possible role in the regulation of the blood brain barrier and angiogenesis. Our results encourage the use of NSCs as a cell-replacement therapy for the treatment of human vascular Parkinsonism.
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Objetivo: Presentar la eficacia de los programas de rehabilitación pulmonar en el tratamiento de un paciente asmático. Caso: joven de 17 años con diagnóstico de asma severa, sintomática desde los 8 años de edad, de raza blanca, estudiante de décimo grado de bachillerato. Remitida al programa de rehabilitación pulmonar luego de tres hospitalizaciones por crisis asmática en el último año, disnea en actividades de la vida diaria e intolerancia al ejercicio. En la valoración inicial se encontró una paciente con asma no controlada, recibiendo medicamentos de acción corta; admitió que no estaba obedeciendo al uso regular y a la dosis del tratamiento farmacológico y que desconocía la importancia de este compromiso para su óptima evolución. Manifestó preocupación por el deterioro respiratorio y funcional progresivo que había tenido en el último año y la presencia de ansiedad y temor al no poder respirar e interactuar en actividades propias de su edad. Un mes después de recibir broncodilatadores y esteroides de larga acción de modo permanente y de acatar las recomendaciones del uso regular y técnica adecuada, la paciente fue incluida en un programa de rehabilitación pulmonar con una frecuencia de tres veces por semana, durante ocho semanas para entrenamiento de fuerza-resistencia de miembros superiores e inferiores y educación. Obtuvo cambios funcionales significativos y mayor participación social.
Objective: to present the effectiveness of pulmonary rehabilitation programs in the treatment of a patient with asthma. Case: this is the case of a young Caucasian girl -17 years old- with severe asthma diagnosis, with symptoms since she was eight years old, 10th grade student. She was referred to the program of Pulmonary Rehabilitation after three hospitalizations during the last year due to asthmatic crises, dyspnoea in activities of daily living, and intolerance to physical exercise. In the initial evaluation, a patient with non-controlled asthma was found; she was receiving short-acting medication admitting that she was not complying with regular use and with a prescribed dose of the pharmacological treatment and that she ignored the importance of this commitment for optimal evolution. The patient expressed concern about the progressive deterioration at her respiratory and functional level during the last year and her fear and anxiety for not being able to breathe during activities befitting her age. One month after receiving bronchodilators and long-acting steroids permanently and complying with recommendations about regular use and adequate inhalatory technique, the patient was included in a three-times-a-week program of pulmonary rehabilitation during eight weeks for upper and lower extremity endurance and resistance training. This intervention showed significant changes in the patient at functional level and a greater social participation.
Objetivo: apresentar a eficácia dos programas de reabilitação pulmonar no tratamento de um paciente com asma. Caso: isto é caso de uma jovem de 17 anos, com diagnóstico de asma grave, sintomática de 8 anos, estudante do segundo ano, o branco na escola. Apresentada no programa de reabilitação pulmonar após três internações por asma no ano passado, dispnéia em atividades de vida diária e intolerância ao exercício. Na avaliação inicial encontramos um paciente com asma não controlada, recebendo curto drogas de ação; admitiendió não estava obedecendo o uso regular e dose de tratamento medicamentoso e não sabia a importância deste compromisso para o desenvolvimento ideal. Manifestou preocupação com o comprometimento funcional respiratória progressiva e que ele tinha no ano passado e a presença de ansiedade e medo de não ser capaz de respirar e interagir em atividades etários adequados. Um mês depois de receber broncodilatadores e corticóides de longa ação permanente e respeitar as recomendações de uso regular e técnica adequada, o paciente foi incluído em um programa de reabilitação pulmonar com uma freqüência de três vezes por semana, por oito semanas de resistência treinamento de força para membros superiores e inferiores e educação. Obtido significativas benefícios funcionais e participação social.
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Humanos , Femenino , Adolescente , Asma , Calidad de Vida , Ejercicio Físico , Educación en Salud , DisneaRESUMEN
Se describe el caso de un varón de 59 años, con diagnóstico de enfermedad pulmonar obstructiva crónica (EPOC) severa, producto del consumo de cigarrillo. En la evaluación, presenta deficiencias en la capacidad aeróbica, en el desempeño muscular, en la ventilación e intercambio gaseoso, con alteración de sus volúmenes pulmonares, las cuales le ocasionaron limitación funcional y restricción en la realización de las actividades de la vida diaria. Se inició un plan de cuidado y acondicionamiento físico, consistente en incrementar la fuerza y resistencia de miembros inferiores y superiores, entrenamiento de músculos respiratorios y un plan de educación individual y grupal acerca del conocimiento y manejo de la enfermedad, además se le brindó soporte psicoterapéutico. Los resultados del programa mostraron efectos positivos en su condición de salud, en general, y en la disminución de su limitación funcional.
We report the case of a 59 year old male with severe chronic obstructive pulmonary disease (COPD) due to cigarette smoking. At the clinical evaluation he presented deficit in his aerobic capabilities, in his muscular performance, in ventilation and gas exchange with variation in lung volume causing functional limitation and restriction in his daily activities. It was designed a therapeutic plan of physical training in order to increase strength and endurance in extremities, training of respiratory muscles and also Individual education and grupal program regarding knowledge and management of his illness along with psychological support. The results of this program showed improvement in his health condition and lessening his functional limitations.
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Humanos , Masculino , Persona de Mediana Edad , Enfermedad Pulmonar Obstructiva Crónica , Rehabilitación , Terapéutica , Acondicionamiento Físico Humano , Mediciones del Volumen PulmonarRESUMEN
Tyrosine hydroxylase (TH)-immunoreactive (ir) neurones are detected in the striatum of animals after dopamine depletion and also in human parkinsonian patients. Although there is extensive evidence for TH-ir neurones in the lesioned rodent striatum, there are few details regarding the molecular phenotype of these neurones, regulation of their TH expression after l-3,4-dihydroxyphenylalanine (L-DOPA) treatment and their function. In the present study, we examined the time-course of appearance of TH-ir neurones in the mouse striatum after 6-hydroxydopamine (6-OHDA) lesion and determined their molecular phenotype. We found that TH-ir neurones appeared in the striatum as early as 3 days after a 6-OHDA lesion. By 1 week after the lesion, the number of TH-ir neurones started to decrease and this decrease progressed significantly over time. Treatment with L-DOPA increased both the number of TH-ir neurones and the intensity of their immunolabelling. The TH-ir neurones that appear after the 6-OHDA lesion in the striatum are not newly generated cells as they did not incorporate 5-bromo-2-deoxyuridine. We found that the vast majority of TH-ir neurones colocalized with dynorphin and enkephalin, suggesting that they are projection neurones of the direct and indirect striatal output pathways. TH-ir neurones did not express the dopamine transporter but half of them expressed amino acid decarboxylase, an enzyme required for dopamine synthesis. Finally, striatal TH-ir neurones are functionally active, expressing the neuronal activation marker FosB in response to L-DOPA treatment. Promotion of these striatal TH-ir neurones may be beneficial in Parkinson's disease, particularly in the early stages when dopamine denervation is incomplete.
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Cuerpo Estriado/metabolismo , Dopamina/deficiencia , Levodopa/metabolismo , Neuronas/enzimología , Sustancia Negra/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , Animales , Biomarcadores/análisis , Biomarcadores/metabolismo , Bromodesoxiuridina , Recuento de Células , Proliferación Celular/efectos de los fármacos , Cuerpo Estriado/citología , Cuerpo Estriado/fisiopatología , Desnervación , Dopamina/biosíntesis , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/metabolismo , Inmunohistoquímica , Levodopa/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Degeneración Nerviosa/inducido químicamente , Degeneración Nerviosa/enzimología , Degeneración Nerviosa/fisiopatología , Vías Nerviosas/metabolismo , Vías Nerviosas/fisiopatología , Neuronas/citología , Neuronas/efectos de los fármacos , Péptidos Opioides/metabolismo , Oxidopamina , Enfermedad de Parkinson/metabolismo , Enfermedad de Parkinson/fisiopatología , Proteínas Proto-Oncogénicas c-fos/metabolismo , Sustancia Negra/fisiopatología , SimpaticolíticosRESUMEN
OBJECT: The results of olfactory ensheathing cell (OEC) transplantation have raised great expectations as a potential treatment for spinal cord injury (SCI). Its capacity to promote functional neural repair, however, remains unclear. The authors studied axonal growth and locomotor recovery after C-7 contusion injury and OEC transplantation in adult rats. METHODS: Twenty-four male Wistar rats underwent a mild C-7 contusion injury that completely disrupted the dorsal corticospinal tract (DCST). In 14 rats OECs were transplanted into the lesion, and 10 were used as controls. At 3 months postcontusion, the kinematics of locomotion were assessed, and the CST was traced by injecting dextran tetramethylrhodamine bilaterally into the cerebral cortex. The animals were killed 2 weeks after tracer injection, and their spinal cords were studied immunohistochemically. Although the survival of transplanted cells varied, they were present in all cases. The authors observed neither OEC migration nor DCST axon regeneration in any of the cell transplant-treated rats. Corticospinal axons ended in retraction bulbs at the proximal edge of the lesion or, exceptionally, a few micrometers inside the transplant. The results of neurofilament immunohistochemical analysis provided evidence of neurites from systems other than the DCST growing into the transplant, but in some cases these neurites formed loops of pathological appearance. Contusion injury of C-7 caused chronic locomotor deficits that did not improve after OEC transplants. CONCLUSIONS: The findings in this study indicate that OEC transplants alone are not sufficient for neural repair and functional recovery after SCI. In addition, OECs can induce abnormal axonal growth, making further studies necessary before considering their clinical use.
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Regeneración Nerviosa/fisiología , Neuroglía/trasplante , Traumatismos de la Médula Espinal/terapia , Animales , Axones , Fenómenos Biomecánicos , Movimiento Celular , Supervivencia Celular , Vértebras Cervicales , Locomoción , Ratas , Ratas Wistar , Traumatismos de la Médula Espinal/veterinaria , Resultado del TratamientoRESUMEN
Important breakthroughs in the understanding regeneration failure in an injured CNS have been made by studies of primary afferent neurons. Dorsal rhizotomy has provided an experimental model of brachial plexus (BP) avulsion. This is an injury in which the central branches of primary afferents are disrupted at their point of entry into the spinal cord, bringing motor and sensory dysfunction to the upper limbs. In the present work, the central axonal organization of primary afferents was examined in control (without lesion) adult Wistar rats and in rats subjected to a C3-T3 rhizotomy. Specific sensory axon subtypes were recognized by application of antibodies to the calcitonin gene-related peptide (CGRP), the P2X3 purinoreceptor, the low-affinity p75-neurotrophin receptor and the retrograde tracer cholera toxin subunit beta (TCbeta). Other subtypes weres labeled with the lectin Griffonia simplicifolia 1B4. Using immunohistochemistry and high resolution light microscopy, brachial plexus rhizotomy in adult rats has proven a reliable model for several neural deficits in humans. This lesion produced different degrees of terminal degeneration in the several types of primary afferents which define sub-populations of sensitive neurons. Between the C6 and C8 levels of the spinal cord,, deafferentation was partial for peptidergic GCRP-positive fibers, in contrast with elimination of non peptidergic and myelinated fibers. Dorsal rhizotomy has provided an adequate experimental model to study sensory alterations such as acute pain and allodynia as well as factors that affect regeneration into the CNS., Therefore, the differential deafferentation response must be considered inr the evaluation of therapies for nociception (pain) and regeneration for brachial plexus avulsion. The anatomical diffierences among the primary afferent subtypes also affect their roles in normal and damaged conditions.
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Plexo Braquial/lesiones , Modelos Animales de Enfermedad , Neuronas Aferentes/patología , Animales , Axones , Masculino , Neuronas Aferentes/citología , Ratas , Ratas Wistar , RizotomíaRESUMEN
Important breakthroughs in the understanding regeneration failure in an injured CNS have been made by studies of primary afferent neurons. Dorsal rhizotomy has provided an experimental model of brachial plexus (BP) avulsion. This is an injury in which the central branches of primary afferents are disrupted at their point of entry into the spinal cord, bringing motor and sensory dysfunction to the upper limbs. In the present work, the central axonal organization of primary afferents was examined in control (without lesion) adult Wistar rats and in rats subjected to a C3-T3 rhizotomy. Specific sensory axon subtypes were recognized by application of antibodies to the calcitonin gene-related peptide (CGRP), the P2X3 purinoreceptor, the low-affinity p75-neurotrophin receptor and the retrograde tracer cholera toxin subunit beta (TCbeta ). Other subtypes weres labeled with the lectin Griffonia simplicifolia IB4. Using immunohistochemistry and high resolution light microscopy, brachial plexus rhizotomy in adult rats has proven a reliable model for several neural deficits in humans. This lesion produced different degrees of terminal degeneration in the several types of primary afferents which define sub-populations of sensitive neurons. Between the C6 and C8 levels of the spinal cord,,deafferentation was partial for peptidergic GCRP-positive fibers, in contrast with elimination of non peptidergic and myelinated fibers. Dorsal rhizotomy has provided an adequate experimental model to study sensory alterations such as acute pain and allodynia as well as factors that affect regeneration into the CNS., Therefore, the differential deafferentation response must be considered inr the evaluation of therapies for nociception (pain) and regeneration for brachial plexus avulsion. The anatomical diffierences among the primary afferent subtypes also affect their roles in normal and damaged conditions.
El uso de las neuronas sensoriales primarias ha aportado avances en el entendimiento de las razones por las cuales falla la regeneración cuando el sistema nervioso central (SNC) es dañado. La rizotomía dorsal se puede usar como un modelo experimental de las lesiones por avulsión del plexo braquial, una lesión en la cual son desprendidas, en su punto de entrada en la médula espinal, las ramas centrales de los aferentes primarios causando una disfunción motora y sensorial grave e irreversible del miembro superior. En el presente trabajo, se examinó la organización central de los aferentes primarios en ratas Wistar adultas. Éstas fueron divididas en controles normales no lesionados y en animales rizotomizados entre los niveles cervical 3 y torácico 3 (C3-T3). Se estudió la deaferentación de los subtipos de axones sensoriales utilizando anticuerpos específicos contra el péptido relacionado con el gen de la calcitonina (CGRP), el receptor purinérgico (P2X3), el receptor de baja afinidad p75 para el factor de crecimiento nervioso (NGF) y contra la subunidad ®de la toxina de cólera (TCbeta ). Otro subtipo fue marcado con la lectina Griffonia simplicifolia IB4. La inmunohistoquímica y la microscopía óptica de alta resolución demostraron que el modelo animal de rizotomía completa del plexo braquial reproduce diversos déficit observados en las lesiones humanas. Esta lesión produce diferentes grados de degeneración terminal entre los diversos tipos de aferentes primarios que definen subpoblaciones de neuronas sensoriales. En los niveles de la médula espinal estudiados (entre C6 y C8), la deaferentación fue parcial para las fibras peptidérgicas GCRPpositivas, en contraste con la eliminación de las fibras no peptidérgicas y las mielinizadas. La rizotomía dorsal es un modelo experimental apropiado para estudiar las alteraciones sensoriales como el dolor agudo y la alodinia, así como los factores que podrían afectar la regeneración en el SNC. Por tanto, la respuesta de deaferentacion diferencial debe ser tenida en cuenta para la evaluación de terapias antinociceptivas y regenerativas tras la avulsión del plexo braquial. Se discute la anatomía de los subtipos de aferentes primarios y su papel en condiciones normales y después de la lesión.
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Animales , Masculino , Ratas , Plexo Braquial/lesiones , Modelos Animales de Enfermedad , Neuronas Aferentes/patología , Axones , Neuronas Aferentes/citología , Ratas Wistar , RizotomíaRESUMEN
The olfactory ensheathing cell (OEC) is a class of glial cell that has been reported to support regeneration in the central nervous system after various types of lesions, including rhizotomy of spinal dorsal roots at thoracic, lumbar and sacral levels. We have therefore carried out a detailed anatomical analysis to assess the efficacy of dorsal horn OEC transplants at promoting regeneration of primary afferents across the dorsal root entry zone (DREZ) at the cervical level in the adult rat. OECs were cultured from adult rat olfactory bulb and immunopurified (90% purity). Regeneration by large diameter afferents and by both peptidergic and non-peptidergic small diameter afferents was assessed using respectively cholera toxin B (CTB) labelling and immunocytochemistry for calcitonin gene-related peptide (CGRP) and the purinoceptor P2X3. Following an extensive (C3-T3) rhizotomy, CGRP and P2X3 immunoreactive axons regenerated across the rhizotomy site as far as the DREZ but there was no evidence of regeneration across the DREZ, except through sites where the OEC transplant was directly grafted into the DREZ. No evidence of regeneration into the dorsal horn by CTB-labelled axons was obtained. In addition, there was little sign of sprouting by intact axons in the vicinity of OEC transplant sites. In contrast to these results in vivo, cocultures of OECs and adult dorsal root ganglion cells showed that OECs stimulate extensive neurite outgrowth. The failure of the OECs to promote regeneration in vivo following cervical rhizotomy is therefore most likely due to factors in the environment of the graft site and/or the method of transplantation.
Asunto(s)
Axones/trasplante , Regeneración Nerviosa/fisiología , Bulbo Olfatorio/trasplante , Nervio Olfatorio/trasplante , Médula Espinal/trasplante , Animales , Axones/fisiología , Vértebras Cervicales/fisiología , Vértebras Cervicales/trasplante , Masculino , Bulbo Olfatorio/citología , Nervio Olfatorio/citología , Ratas , Ratas Wistar , Médula Espinal/fisiología , Raíces Nerviosas Espinales/fisiologíaRESUMEN
La actividad que promueve el crecimiento de axones por la glia envolvente (GE) del bulbo olfatorio depemde de la expresión de diversas moléculas durante el desarrollo, la vida adulta y la reparación de lesiones nerviosas. Diversas moléculas tales como las neurotrofinas y sus receptores, los factores de crecimiento, las moléculas de adhesión celular, las moléculas de matriz extracelular y las moleculas asociadas con la mielinización son producidas por la glia del sistema olfatorio durante el desarrollo. Su expresion sostenida durante la vida adulta parece estar asociada con el reemplazo celular y la alta plasticidad de este sistema. A su vez, su expresión se involucra en procesos de reparación de lesiones mediados por trasplantes de glia. La migración de la GE, que acompaña axones en crecimiento, se observa durante el desarrollo y en procesos de regeneración luego de una lesión. Los trasplantes de GE permiten la navegación de brotes regenerantes a través del tejido gliótico inhbidor formado luego de una lesión del sistema nervioso central. El propósito de esta revisión es profundizar en los mecanismos de actividad promotora de crecimiento axonal
Asunto(s)
Ratas , Axones , Regeneración Nerviosa , Neuroglía , Receptores de Factores de Crecimiento , Bulbo OlfatorioRESUMEN
Mycobacterium leprae es un patógeno intracelular con marcada afinidad por células de Schwann (CS) y macrófagos del sistema reticuloendotelial, que causa una neuropatía periférica en el hombre. Es un microorganismo no cultivable en medios convencionales y numerosos intentos por cultivarlo han sido infructuosos. Los modelos animales utilizados, han sido los de elección, entre estos el del cojinete plantar del ratón que es la prueba oro utilizada en el diagnóstico y el estudio de la patogenesis de la enfermedad, la viabilidad y la resistencia a antibióticos por parte del M. leprae. Conociendo que todos los tipos de lepra (LL,LT, etc.) cursan con una lepra de tipo neural, consideramos que un modelo in vitro de CS de ratón permitiría una gran aproximación al estudio de la interacción del M. leprae y su célula blanco específica en la infección, la cual se puede obtener en cultivo, conservando propiedades morfológicas y funcionales tales como es su capacidad de asociación con neuritas. Aunque las CS comprenden el 90 por ciento de la población inicial en cultivos de ganglios de raíz dorsal (DRG), su número declina debido a la rápida rata mitótica de los fibroblastos en presencia de suero fetal bovino. Sin embargo el tratamiento de los cultivos con agentes activadores del AMP cíclico inhiben el crecimiento de fibroblastos sin causar toxicidad a la CS, permitiendo su proliferación y enriquecimiento. Utilizando un tratamiento con agentes activadores del AMPc se obtuvieron cultivos enriquecidos en células de Schwann, lo cual fue corroborado por recuentos basados en sus características morfológicas y su inmunoreactividad al anticuerpo dirigido contra la proteína S-100, una proteína reguladora de la concentración de calcio intracelular, asociada a filamentos intermedios, presente en la célula de Schwann y ausente en los fibroblastos. Obtuvimos cultivos con un 88 por ciento de células de Schwann los cuales han sido usados en los ensayos de infección. Para la infección de células de Schwann por el Mycobacterium leprae, se utilizó la técnica recomendada por la O.M.S. de obtención y cuantificación de los bacilos a partir de lepromas obtenidos de pacientes con lepra lepromatosa no tratados. Cultivos enriquecidos en células de Schwann se incubaron con este M. leprae y se realizaron estudios morfológicos por microscopía óptica, usando la coloración de Zielh Neelsen caliente cuantificando el número de bacilos por célula y el porcentaje de células infectadas, estudios de...