RESUMEN
Several pathophysiological processes involve Hypoxia conditions, where the nervous system is affected as well. We postulate that the GABAergic system is especially sensitive. Furthermore, drugs improving the resistance to hypoxia have been investigated, such as the neurosteroid dehydroepiandrosterone sulfate (DHEAS) which has shown beneficial effects in hypoxic processes in mammals; however, at the cellular level, its exact mechanism of action has yet to be fully elucidated. Here, we used a chemical hypoxia model through sodium sulfite (SS) exposure in Caenorhabditis elegans (C. elegans), a nematode whose response to hypoxia involves pathways and cellular processes conserved in mammals, and that allows study the direct effect of DHEAS without its conversion to sex hormones. This work aimed to determine the effect of DHEAS on damage to the GABAergic system associated with SS exposure in C. elegans. Worms were subjected to nose touch response (Not Assay) and observed in epifluorescence microscopy. DHEAS decreased the shrinkage response of Not Assay and the level of damage in GABAergic neurons on SS-exposed worms. Also, the enhanced nuclear localization of DAF-16 and consequently the overexpression of chaperone HSP-16.2 by hypoxia were significantly reduced in SS + DHEAS exposed worms. As well, DHEAS increased the survival rate of worms exposed to hydrogen peroxide. These results suggest that hypoxia-caused damage over the GABAergic system was prevented at least partially by DHEAS, probably through non-genomic mechanisms that involve its antioxidant properties related to its chemical structure.
Asunto(s)
Antioxidantes/farmacología , Proteínas de Caenorhabditis elegans/efectos de los fármacos , Sulfato de Deshidroepiandrosterona/farmacología , Factores de Transcripción Forkhead/efectos de los fármacos , Neuronas GABAérgicas/efectos de los fármacos , Proteínas de Choque Térmico/efectos de los fármacos , Hipoxia/metabolismo , Sulfitos/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Factores de Transcripción Forkhead/metabolismo , Neuronas GABAérgicas/metabolismo , Neuronas GABAérgicas/patología , Proteínas de Choque Térmico/metabolismo , Peróxido de Hidrógeno/toxicidad , Hipoxia/patología , Microscopía Fluorescente , Oxidantes/toxicidad , Transducción de Señal , Tasa de SupervivenciaRESUMEN
GABAergic medium spiny neurons are the main neuronal population in the striatum. Calbindin is preferentially expressed in medium spiny neurons involved in the indirect pathway. The aim of the present work is to analyze the effect of perinatal asphyxia on different subpopulations of GABAergic neurons in the striatum and to assess the outcome of deep therapeutic hypothermia. The uterus of pregnant rats was removed by cesarean section and the fetuses were exposed to hypoxia by immersion in water (19 min) at 37°C (perinatal asphyxia). The hypothermic group was exposed to 10°C during 30 min after perinatal asphyxia. The rats were euthanized at the age of one month (adolescent/adult rats), their brains were dissected out and coronal sections were immunolabeled for calbindin, calretinin, NeuN, and reelin. Reelin+ cells showed no staining in the striatum besides subventricular zone. The perinatal asphyxia (PA) group showed a significant decrease in calbindin neurons and a paradoxical increase in neurons estimated by NeuN staining. Moreover, calretinin+ cells, a specific subpopulation of GABAergic neurons, showed an increase caused by PA. Deep hypothermia reversed most of these alterations probably by protecting calbindin neurons. Similarly, there was a reduction of the diameter of the anterior commissure produced by the asphyxia that was prevented by hypothermic treatment.
Asunto(s)
Asfixia Neonatal/terapia , Cuerpo Estriado/patología , Discinesias/prevención & control , Hipotermia Inducida/métodos , Trastornos Psicóticos/prevención & control , Animales , Animales Recién Nacidos , Comisura Anterior Cerebral/patología , Encéfalo/metabolismo , Encéfalo/patología , Calbindina 2/metabolismo , Calbindinas/metabolismo , Moléculas de Adhesión Celular Neuronal/metabolismo , Cuerpo Estriado/metabolismo , Discinesias/etiología , Proteínas de la Matriz Extracelular/metabolismo , Femenino , Neuronas GABAérgicas/metabolismo , Neuronas GABAérgicas/patología , Masculino , Proteínas del Tejido Nervioso/metabolismo , Embarazo , Trastornos Psicóticos/etiología , Ratas , Ratas Sprague-Dawley , Proteína Reelina , Serina Endopeptidasas/metabolismoRESUMEN
INTRODUCTION: Cerebral ischemia is the third leading cause of death and the primary cause of permanent disability worldwide. Atorvastatin is a promising drug with neuroprotective effects that may be useful for the treatment of stroke. However, the effects of atorvastatin on specific neuronal populations within the nigrostriatal system following cerebral ischemia are unknown. OBJECTIVE: To evaluate the effects of atorvastatin on dopaminergic and GABAergic neuronal populations in exofocal brain regions in a model of transient occlusion of the middle cerebral artery. MATERIALS AND METHODS: Twenty-eight male eight-week-old Wistar rats were used in this study. Both sham and ischemic rats were treated with atorvastatin (10 mg/kg) or carboxymethylcellulose (placebo) by gavage at 6, 24, 48 and 72 hours post-reperfusion. We analyzed the immunoreactivity of glutamic acid decarboxylase and tyrosine hydroxylase in the globus pallidus, caudate putamen and substantia nigra. RESULTS: We observed neurological damage and cell loss in the caudate putamen following ischemia. We also found an increase in tyrosine hydroxylase immunoreactivity in the medial globus pallidus and substantia nigra reticulata, as well as a decrease in glutamic acid decarboxylase immunoreactivity in the lateral globus pallidus in ischemic animals treated with a placebo. However, atorvastatin treatment was able to reverse these effects, significantly decreasing tyrosine hydroxylase levels in the medial globus pallidus and substantia nigra reticulata and significantly increasing glutamic acid decarboxylase levels in the lateral globus pallidus. CONCLUSION: Our data suggest that post-ischemia treatment with atorvastatin can have neuro-protective effects in exofocal regions far from the ischemic core by modulating the GABAergic and dopaminergic neuronal populations in the nigrostriatal system, which could be useful for preventing neurological disorders.
Asunto(s)
Cuerpo Estriado/efectos de los fármacos , Neuronas Dopaminérgicas/efectos de los fármacos , Neuronas GABAérgicas/efectos de los fármacos , Ácidos Heptanoicos/uso terapéutico , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Ataque Isquémico Transitorio/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Pirroles/uso terapéutico , Sustancia Negra/efectos de los fármacos , Animales , Atorvastatina , Conducta Animal , Cuerpo Estriado/irrigación sanguínea , Cuerpo Estriado/patología , Neuronas Dopaminérgicas/enzimología , Neuronas Dopaminérgicas/patología , Evaluación Preclínica de Medicamentos , Inducción Enzimática/efectos de los fármacos , Neuronas GABAérgicas/enzimología , Neuronas GABAérgicas/patología , Glutamato Descarboxilasa/biosíntesis , Glutamato Descarboxilasa/genética , Ácidos Heptanoicos/farmacología , Infarto de la Arteria Cerebral Media/patología , Ataque Isquémico Transitorio/patología , Masculino , Trastornos del Movimiento/etiología , Trastornos del Movimiento/prevención & control , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Fármacos Neuroprotectores/farmacología , Pirroles/farmacología , Ratas , Ratas Wistar , Recuperación de la Función , Trastornos de la Sensación/etiología , Trastornos de la Sensación/prevención & control , Organismos Libres de Patógenos Específicos , Sustancia Negra/irrigación sanguínea , Sustancia Negra/patología , Tirosina 3-Monooxigenasa/biosíntesis , Tirosina 3-Monooxigenasa/genéticaRESUMEN
Introduction: Cerebral ischemia is the third leading cause of death and the primary cause of permanent disability worldwide. Atorvastatin is a promising drug with neuroprotective effects that may be useful for the treatment of stroke. However, the effects of atorvastatin on specific neuronal populations within the nigrostriatal system following cerebral ischemia are unknown. Objective: To evaluate the effects of atorvastatin on dopaminergic and GABAergic neuronal populations in exofocal brain regions in a model of transient occlusion of the middle cerebral artery. Materials and methods: Twenty-eight male eight-week-old Wistar rats were used in this study. Both sham and ischemic rats were treated with atorvastatin (10 mg/kg) or carboxymethylcellulose (placebo) by gavage at 6, 24, 48 and 72 hours post-reperfusion. We analyzed the immunoreactivity of glutamic acid decarboxylase and tyrosine hydroxylase in the globus pallidus, caudate putamen and substantia nigra. Results: We observed neurological damage and cell loss in the caudate putamen following ischemia. We also found an increase in tyrosine hydroxylase immunoreactivity in the medial globus pallidus and substantia nigra reticulata, as well as a decrease in glutamic acid decarboxylase immunoreactivity in the lateral globus pallidus in ischemic animals treated with a placebo. However, atorvastatin treatment was able to reverse these effects, significantly decreasing tyrosine hydroxylase levels in the medial globus pallidus and substantia nigra reticulata and significantly increasing glutamic acid decarboxylase levels in the lateral globus pallidus. Conclusion: Our data suggest that post-ischemia treatment with atorvastatin can have neuro-protective effects in exofocal regions far from the ischemic core by modulating the GABAergic and dopaminergic neuronal populations in the nigrostriatal system, which could be useful for preventing neurological disorders.
Introducción. La isquemia cerebral es la tercera causa de muerte y la primera de discapacidad permanente en el mundo. La atorvastatina es un fármaco neuroprotector prometedor para el tratamiento de la apoplejía; sin embargo, su acción sobre las poblaciones neuronales del sistema nigroestriatal después de la isquemia aún se desconoce. Objetivo. Evaluar el efecto de la atorvastatina sobre poblaciones gabérgicas y dopaminérgicas en regiones exofocales en un modelo de oclusión transitoria de la arteria cerebral media. Materiales y métodos. Se utilizaron 28 ratas Wistar macho de ocho semanas de edad. Los ejemplares con isquemia simulada y los ejemplares sometidos a isquemia fueron tratados con atorvastatina (10 mg/kg) y carboximetilcelulosa (placebo) administrados por medio de sonda a las 6, 24, 48 y 72 horas después de la reperfusión. Se analizó la inmunorreacción de la descarboxilasa del ácido glutámico y de la tirosina hidroxilasa en el globo pálido, el putamen caudado y la sustancia negra. Resultados. Los datos confirmaron el daño neurológico y la pérdida celular en el putamen caudado. Se incrementó la inmunorreacción de la tirosina hidroxilasa en el globo pálido medial y la sustancia negra pars reticulata , disminuyendo la inmunorreacción de la descarboxilasa del ácido glutámico en el globo pálido lateral de los animales isquémicos tratados con placebo; sin embargo, el tratamiento con atorvastatina pudo revertirla, lo que logró una disminución significativa de la tirosina hidroxilasa en el globo pálido medial y la sustancia negra pars reticulata y aumentando los niveles de descarboxilasa del ácido glutámico en el globo pálido lateral. Conclusión. Nuestros datos sugieren que la atorvastatina en el tratamiento posterior a la isquemia ejerce neuroprotección en las zonas exofocales, modulando las poblaciones neuronales gabérgicas y dopaminérgicas del sistema nigroestriatal, lo que podría prevenir trastornos neurológicos.
Asunto(s)
Animales , Masculino , Ratas , Cuerpo Estriado/efectos de los fármacos , Neuronas Dopaminérgicas/efectos de los fármacos , Neuronas GABAérgicas/efectos de los fármacos , Ácidos Heptanoicos/uso terapéutico , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Ataque Isquémico Transitorio/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Pirroles/uso terapéutico , Sustancia Negra/efectos de los fármacos , Conducta Animal , Cuerpo Estriado/irrigación sanguínea , Cuerpo Estriado/patología , Evaluación Preclínica de Medicamentos , Neuronas Dopaminérgicas/enzimología , Neuronas Dopaminérgicas/patología , Inducción Enzimática/efectos de los fármacos , Neuronas GABAérgicas/enzimología , Neuronas GABAérgicas/patología , Glutamato Descarboxilasa/biosíntesis , Glutamato Descarboxilasa/genética , Ácidos Heptanoicos/farmacología , Infarto de la Arteria Cerebral Media/patología , Ataque Isquémico Transitorio/patología , Trastornos del Movimiento/etiología , Trastornos del Movimiento/prevención & control , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Fármacos Neuroprotectores/farmacología , Pirroles/farmacología , Ratas Wistar , Recuperación de la Función , Organismos Libres de Patógenos Específicos , Trastornos de la Sensación/etiología , Trastornos de la Sensación/prevención & control , Sustancia Negra/irrigación sanguínea , Sustancia Negra/patología , /biosíntesis , /genéticaRESUMEN
Cerebral hypoxia-ischemia damages synaptic proteins, resulting in cytoskeletal alterations, protein aggregation and neuronal death. In the previous works, we have shown neuronal and synaptic changes in rat neostriatum subjected to hypoxia that leads to ubi-protein accumulation. Recently, we also showed that, changes in F-actin organization could be related to early alterations induced by hypoxia in the Central Nervous System. However, little is known about effective treatment to diminish the damage. The main aim of this work is to study the effects of birth hypothermia on the actin cytoskeleton of neostriatal post-synaptic densities (PSD) in 60 days olds rats by immunohistochemistry, photooxidation and western blot. We used 2 different protocols of hypothermia: (a) intrahypoxic hypothermia at 15°C and (b) post-hypoxia hypothermia at 32°C. Consistent with previous data at 30 days, staining with phalloidin-Alexa(488) followed by confocal microscopy analysis showed an increase of F-actin fluorescent staining in the neostriatum of hypoxic animals. Correlative photooxidation electron microscopy confirmed these observations showing an increment in the number of mushroom-shaped F-actin staining spines in neostriatal excitatory synapses in rats subjected to hypoxia. In addition, western blot revealed ß-actin increase in PSDs in hypoxic animals. The optic relative density measurement showed a significant difference between controls and hypoxic animals. When hypoxia was induced under hypothermic conditions, the changes observed in actin cytoskeleton were blocked. Post-hypoxic hypothermia showed similar answer but actin cytoskeleton modifications were not totally reverted as we observed at 15°C. These data suggest that the decrease of the body temperature decreases the actin modifications in dendritic spines preventing the neuronal death.