[Atorvastatin-meloxicam association inhibits neuroinflammation and attenuates the cellular damage in cerebral ischemia by arterial embolism]. / La combinación de atorvastatina y meloxicam inhibe la neuroinflamación y atenúa el daño celular en la isquemia cerebral experimental por embolia arterial.

INTRODUCTION: Stroke is the second leading cause of death and the first cause of disability in the world, with more than 85% of the cases having ischemic origin. OBJECTIVE: To evaluate in an embolism model of stroke the effect of atorvastatin and meloxicam on neurons, astrocytes and microglia. This evaluation was done administering each medication individually and in association. MATERIALS AND METHODS: Wistar rats were subjected to carotid arterial embolism and treatment with meloxicam and atorvastatin at 6, 24, 48 and 72 hours. Using immunohistochemistry, we evaluated the immunoreactivity of COX-2 protein, GFAP and OX-42 in neurons, astrocytes and microglia by densitometric and morphological studies. Data were evaluated by variance analysis and non-parametric multiple comparison. RESULTS: Cerebral ischemia by arterial embolism increased significantly the reactivity of microglia and astrocytes (p<0.001), whereas it was reduced by atorvastatin, meloxicam and their association. Ischemia produced astrocytic shortening, cellular thickening, protoplasmic rupture expansions (clasmatodendrosis) and microglial morphological changes characteristic of various activity stages. In perifocal areas, immunoreactivity of COX-2 was increased and in the ischemic focus it was reduced, while meloxicam and atorvastatin significantly reduced (p<0.001) perifocal immunoreactivity, restoring the marking of cyclooxygenase in the ischemic focus. CONCLUSION: These results suggest that the meloxicam-atorvastatin association attenuates astrocytic and microglial response in the inflammatory process after cerebral ischemia by arterial embolism, reducing neurodegeneration and restoring the morphological and functional balance of nervous tissue .

Atorvastatin protects GABAergic and dopaminergic neurons in the nigrostriatal system in an experimental rat model of transient focal cerebral ischemia.

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.

Atorvastatin protects GABAergic and dopaminergic neurons in the nigrostriatal system in an experimental rat model of transient focal cerebral ischemia / La atorvastatina protege las neuronas gabérgicas y dopaminérgicas del sistema nigroestriatal en un modelo experimental de isquemia cerebral focal transitoria en ratas

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.

La asociación atorvastatina-meloxicam reduce el daño cerebral, atenuando la gliosis reactiva consecuente a embolismo arterial / The association atorvastatin-meloxicam reduces brain damage, attenuating reactive gliosis subsequent to arterial embolism

Introducción: el accidente cerebrovascular es la primera causa de discapacidad y la tercera de muerte en Colombia y en el resto del mundo y está asociado a enfermedades mentales y neurodegenerativas. Objetivo: determinar los efectos de la asociación atorvastatina-meloxicam sobre la gliosis reactiva en un modelo de isquemia cerebral por embolización arterial. Materiales y métodos: se utilizaron 56 ratas Wistar macho adultas, distribuidas en cuatro grupos isquémicos y cuatro controles, además de otras 10 para determinar la distribución y extensión del infarto, induciendo lesión en seis de ellas y simulación (sham) en las cuatro restantes. Los tratamientos fueron: placebo, atorvastatina (ATV), meloxicam (MELOX) y ATV + MELOX en isquémicos y simulados. Veinticuatro horas después de la isquemia se evaluó la actividad enzimática mitocondrial con trifeniltetrazolio (TTC) y a las 120 horas, la reactividad astrocitaria (anti-GFAP), mediante inmunohistoquímica convencional. Resultados: la asociación ATV+MELOX favoreció la modulación en la respuesta de los astrocitos protoplasmáticos y fibrosos del hipocampo y de la zona paraventricular, reduciendo su hiperreactividad. Conclusión: ATV y MELOX, aisladamente o asociados, reducen el daño cerebral atenuando la gliosis reactiva consecuente a la embolización arterial, lo que sugiere nuevos mecanismos de neuroprotección frente a la isquemia cerebral tromboembólica y abre nuevas perspectivas para su tratamiento temprano.

Introduction: Stroke is the leading cause of disability and the third of death in Colombia and in the world and it is associated with neurodegenerative and mental diseases. Objective: To determine the effects of the atorvastatin- meloxicam association on reactive gliosis in a model of cerebral ischemia produced by arterial embolization. Materials and methods: 56 adult male Wistar rats were used, divided into four ischemic and four control groups, plus 10 additional animals to determine the distribution and extent of infarction by injury in six of them and simulation (sham) in the remaining four. The treatments were: placebo, atorvastatin (ATV), meloxicam (MELOX) and ATV + MELOX in ischemic and simulated animals. 24 hours post-ischemia mitochondrial enzymatic activity was evaluated with triphenyl- tetrazolium (TTC), and at 120 hours astrocytic reactivity (anti-GFAP) was analyzed by conventional immunohistochemistry. Results: The association ATV + MELOX favored the modulation of the response of protoplasmatic and fibrous astrocytes in both the hippocampus and the paraventricular zone by reducing their hypereactivity. Conclusion: Atorvastatin and meloxicam, either individually or associated, reduce cerebral damage by lessening the reactive gliosis produced by arterial embolization; this suggests new mechanisms of neuroprotection against thromboembolic cerebral ischemia, and opens new perspectives in its early treatment.

Análisis comparativo de marcadores de lesión en modelos de isquemia cerebral focal y global en ratas / Injury markers in two models of cerebral ischemia

Introducción. Los indicadores espacio-temporales de lesión son esenciales en el estudio neuropatológico y terapéutico de la isquemia cerebral. Objetivo. Optimizar la técnica de dos modelos de isquemia cerebral (focal y global) y hacer un análisis comparativo de la progresión del daño cerebral, mediante marcadores de neurodegeneración. Materiales y métodos. Se sometieron ratas Wistar a oclusión temporal de la arteria cerebral media o a oclusión de cuatro vasos, y se evaluaron comparativamente el tiempo quirúrgico, la tasa de supervivencia y la recuperación neurológica. Se utilizó trifenilo de tetrazolio para establecer la distribución del infarto y tinción con Fluoro - Jade B ® como marcador de neurodegeneración. La inmunorreacción de la astroglía se evaluó con el anticuerpo contra la proteína acídica fibrilar de la glía ( Glial Fibrillary Acidic Protein, GFAP) y el anticuerpo AT-8 contra la proteína tau hiperfosforilada, 24, 48 y 72 horas después de la isquemia. Resultados. Los modelos de isquemia utilizados requirieron menor tiempo quirúrgico y hubo menor riesgo de muerte, respecto a estudios previos. En el modelo focal, las células positivas con Fluoro - Jade B ® y los astrocitos reactivos, se evidenciaron en corteza e hipocampo a las 24 horas después de la isquemia. En el modelo global, se observó tinción Fluoro - Jade B ® positiva a las 24 horas, aumentando significativamente la reacción de la GFAP a las 72 horas en corteza y a las 48 horas en el hipocampo. La reacción contra la proteína tau hiperfosforilada aumentó progresivamente y fue máxima a las 72 horas en ambos modelos. Conclusiones. Los dos modelos de isquemia cerebral, oclusión temporal de la arteria cerebral media y oclusión de cuatro vasos, fueron optimizados. En estos modelos, los marcadores la tinción Fluoro - Jade B ® y la GFAP permitieron detectar procesos de neurodegeneración 24 horas después de la isquemia, en tanto el marcador de proteína tau hiperfosforilada (AT-8) incrementó progresivamente su reacción hasta las 72 horas, lo cual sugiere la propagación de la excitotoxicidad y la alteración de enzimas implicadas en la fosforilación de proteínas del citoesqueleto.

Introduction: Spatio-temporal indicators of injury are essential for the study of neuropathological processes and for developing therapeutic approaches for stroke. Objective: This study sought to optimize the techniques of two cerebral ischemia models (focal and global) and to comparatively evaluate the progression of brain damage by analyzing markers of neurodegeneration. Materials and methods: Wistar rats were subjected to temporary occlusion of the middle cerebral artery (t-MCAO) or four-vessel occlusion (4-VO), and surgical time, survival rate and neurological recovery were comparatively evaluated. Triphenyl tetrazolium was used to determine the distribution of the infarction, and Fluoro-Jade B was used as a marker of neurodegeneration. Astroglial immunoreactivity was assessed with an anti-glial fibrillary acidic protein (GFAP) antibody, and an anti-AT-8 antibody was used to detect hyperphosphorylated tau protein at 24, 48 and 72 hours post-ischemia. Results: The cerebral ischemia models employed (t-MCAO and 4-VO) required less surgical time and presented less of a death risk compared to those in previous studies. In the focal model, Fluoro-Jadepositive cells and reactive astrocytes were observed in the cerebral cortex and the hippocampus at 24 hours post-ischemia. In the global model, we observed Fluoro-Jade-positive cells at 24 hours, and a significant increase in the reactivity of GFAP was observed at 72 hours in the cortex and at 48 hours in the hippocampus. The immunoreactivity of hyperphosphorylated tau protein increased progressively, reaching a maximum at 72 hours post-ischemia in both models. Conclusions: These results suggest that in the t-MCAO and 4-VO ischemia models, the expression of Fluoro-Jade and GFAP indicates early neurodegeneration at 24 hours post-insult. In contrast, the immunoreactivity of the hyperphosphorylated tau protein marker (AT-8) progressively increases until 72 hours post-insult, which suggests that the progression of excitotoxicity and alteration of enzymes involves the phosphorylation of cytoskeletal proteins.

[Injury markers in two models of cerebral ischemia]. / Análisis comparativo de marcadores de lesión en modelos de isquemia cerebral focal y global en ratas.

INTRODUCTION: Spatio-temporal indicators of injury are essential for the study of neuropathological processes and for developing therapeutic approaches for stroke. OBJECTIVE: This study sought to optimize the techniques of two cerebral ischemia models (focal and global) and to comparatively evaluate the progression of brain damage by analyzing markers of neurodegeneration. MATERIALS AND METHODS: Wistar rats were subjected to temporary occlusion of the middle cerebral artery (t-MCAO) or four-vessel occlusion (4-VO), and surgical time, survival rate and neurological recovery were comparatively evaluated. Triphenyl tetrazolium was used to determine the distribution of the infarction, and Fluoro-Jade B was used as a marker of neurodegeneration. Astroglial immunoreactivity was assessed with an anti-glial fibrillary acidic protein (GFAP) antibody, and an anti-AT-8 antibody was used to detect hyperphosphorylated tau protein at 24, 48 and 72 hours post-ischemia. RESULTS: The cerebral ischemia models employed (t-MCAO and 4-VO) required less surgical time and presented less of a death risk compared to those in previous studies. In the focal model, Fluoro-Jadepositive cells and reactive astrocytes were observed in the cerebral cortex and the hippocampus at 24 hours post-ischemia. In the global model, we observed Fluoro-Jade-positive cells at 24 hours, and a significant increase in the reactivity of GFAP was observed at 72 hours in the cortex and at 48 hours in the hippocampus. The immunoreactivity of hyperphosphorylated tau protein increased progressively, reaching a maximum at 72 hours post-ischemia in both models. CONCLUSIONS: These results suggest that in the t-MCAO and 4-VO ischemia models, the expression of Fluoro-Jade and GFAP indicates early neurodegeneration at 24 hours post-insult. In contrast, the immunoreactivity of the hyperphosphorylated tau protein marker (AT-8) progressively increases until 72 hours post-insult, which suggests that the progression of excitotoxicity and alteration of enzymes involves the phosphorylation of cytoskeletal proteins.