RESUMEN
To date, there have been three common methods for sampling the cerebral ischemic border zone in a rat model of transient middle cerebral artery occlusion (tMCAO): the "two o'clock method", the "diagonal method", and the "parallel line method". However, these methods have their own advantages and limitations. Here, we propose a modified technique (the "rectangular method") for sampling the ischemic border zone. A rat tMCAO model was prepared under the support of a compact small animal anesthesia machine. Cerebral blood flow was monitored by high-resolution laser Doppler to control the quality of modeling, and 2,3,5-triphenyl tetrazolium chloride (TTC) staining was used for cerebral infarction location assessment. Superoxide dismutase 2 (SOD2), cysteinyl aspartate specific proteinase (caspase)-3, caspase-9, and heat shock protein 70 (HSP70) were used to verify the reliability and reproducibility of the rectangular method. The expression of biomarkers (SOD2, caspase-3, caspase-9, and HSP70) in the traditional (two o'clock method after TTC staining) and modified (rectangular method) groups were increased. There were no significant differences between the groups. The rectangular method proposed herein is based on a modification of the diagonal method and parallel line method, which could provide a directly observable infarct borderline and a sufficient sampling area for subsequent experimental operations regardless of the cerebral infarct location. The assessed biomarkers (SOD2, caspase-3, caspase-9, and HSP70) demonstrated the reliability and reproducibility of the rectangular method, which may facilitate inter-laboratory comparisons.
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Spontaneous recovery after a stroke accounts for a significant part of the neurological recovery in patients. However limited, the spontaneous recovery is mechanistically driven by axonal restorative processes for which several molecular cues have been previously described. We report the acceleration of spontaneous recovery in a preclinical model of ischemia/reperfusion in rats via a single intracerebroventricular administration of extracellular vesicles released from primary cortical astrocytes. We used magnetic resonance imaging and confocal and multiphoton microscopy to correlate the structural remodeling of the corpus callosum and striatocortical circuits with neurological performance during 21 days. We also evaluated the functionality of the corpus callosum by repetitive recordings of compound action potentials to show that the recovery facilitated by astrocytic extracellular vesicles was both anatomical and functional. Our data provide compelling evidence that astrocytes can hasten the basal recovery that naturally occurs post-stroke through the release of cellular mediators contained in extracellular vesicles.
Asunto(s)
Vesículas Extracelulares , Accidente Cerebrovascular , Animales , Astrocitos , Axones , Modelos Animales de Enfermedad , Humanos , Imagen por Resonancia Magnética , Ratas , Recuperación de la Función/fisiología , Accidente Cerebrovascular/patologíaRESUMEN
The present study describes the electroencephalographic changes that occur during cerebral ischemia and reperfusion in animals submitted to transient focal cerebral ischemia by middle cerebral artery occlusion (MCAO) for 30 min. For this, male Wistar rats were divided into two groups (n = 6 animals/group): (1) sham (control) group, and (2) ischemic/reperfusion group. The quantitative electroencephalography (qEEG) was recorded during the ischemic and immediate reperfusion (acute) phases, and then once a day for 7 days after the MCAO (subacute phase). The acute phase was characterized by a marked increase in the relative delta wave band power (p < 0.001), with a smaller, but significant increase in the relative alpha wave bandpower in the ischemic stroke phase, in comparison with the control group (p = 0.0054). In the immediate reperfusion phase, however, there was an increase in the theta, alpha, and beta waves bandpower (p < 0.001), but no alteration in the delta waves (p = 0.9984), in comparison with the control group. We also observed high values in the delta/theta ratio (DTR), the delta/alpha ratio (DAR), and the (delta+theta)/(alpha+beta) ratio (DTABR) indices during the ischemia (p < 0.05), with a major reduction in the reperfusion phase. In the subacute phase, the activity of all the waves was lower than that of the control group (p < 0.05), although the DTR, DAR, and DTABR indices remained relatively high. In conclusion, early and accurate identification of decreased delta wave bandpower, DTR, DAR, and DTABR indices, and an increase in the activity of other waves in the immediate reperfusion phase may represent an important advance for the recognition of the effectiveness of reperfusion therapy.
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Stroke is frequently associated with severe neurological decline and mortality, and its incidence is expected to increase due to aging population. The only available pharmacological treatment for cerebral ischemia is thrombolysis, with narrow therapeutic windows. Efforts aimed to identify new therapeutics are crucial. In this study, we look into plausible molecular and cellular targets for JM-20, a new hybrid molecule, against ischemic stroke in vivo. Male Wistar rats were subjected to 90 min middle cerebral artery occlusion (MCAO) following 23 h of reperfusion. Animals treated with 8 mg/kg JM-20 (p.o., 1 h after reperfusion) showed minimal neurological impairment and lower GABA and IL-1ß levels in CSF when compared to damaged rats that received vehicle. Immunocontent of pro-survival, phosphorylated Akt protein decreased in the cortex after 24 h as result of the ischemic insult, accompanied by decreased number of NeuN+ cells in the peri-infarct cortex, cornu ammonis 1 (CA1) and dentate gyrus (DG) areas. Widespread reactive astrogliosis in both cortex and hippocampus (CA1, CA3, and DG areas) was observed 24 h post-ischemia. JM-20 prevented the activated Akt reduction, neuronal death, and astrocytes reactivity throughout the brain. Overall, the results reinforce the pharmacological potential of JM-20 as neuroprotective agent and provide important evidences about its molecular and cellular targets in this model of cerebral ischemia.
Asunto(s)
Astrocitos/patología , Benzodiazepinas/uso terapéutico , Infarto Encefálico/tratamiento farmacológico , Encéfalo/patología , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/patología , Neuronas/patología , Niacina/análogos & derivados , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Benzodiazepinas/farmacología , Infarto Encefálico/líquido cefalorraquídeo , Infarto Encefálico/patología , Región CA3 Hipocampal/efectos de los fármacos , Región CA3 Hipocampal/metabolismo , Región CA3 Hipocampal/patología , Muerte Celular/efectos de los fármacos , Giro Dentado/efectos de los fármacos , Giro Dentado/metabolismo , Giro Dentado/patología , Proteína Ácida Fibrilar de la Glía/metabolismo , Gliosis/metabolismo , Gliosis/patología , Infarto de la Arteria Cerebral Media/líquido cefalorraquídeo , Interleucina-10/líquido cefalorraquídeo , Interleucina-1beta/líquido cefalorraquídeo , Masculino , Neuronas/efectos de los fármacos , Niacina/farmacología , Niacina/uso terapéutico , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Wistar , Resultado del Tratamiento , Ácido gamma-Aminobutírico/líquido cefalorraquídeoRESUMEN
Stroke is the second leading cause of death worldwide. Brain imaging data from experimental rodent stroke models suggest that size and location of the ischemic lesion relate to behavioral outcome. However, such a relationship between these two variables has not been established in Non-Human Primate (NHP) models. Thus, we aimed to evaluate whether size, location, and severity of stroke following controlled Middle Cerebral Artery Occlusion (MCAO) in NHP model correlated to neurological outcome. Forty cynomolgus macaques underwent MCAO, after four mortalities, thirty-six subjects were followed up during the longitudinal study. Structural T2 scans were obtained by magnetic resonance imaging (MRI) prior to, 48â¯h, and 30 days post-MCAO. Neurological function was assessed with the Non-human Primate Stroke Scale (NHPSS). T2 whole lesion volume was calculated per subject. At chronic stages, remaining brain volume was computed, and the affected hemisphere parceled into 50 regions of interest (ROIs). Whole and parceled volumetric measures were analyzed in relation to the NHPSS score. The longitudinal lesion volume evaluation showed a positive correlation with the NHPSS score, whereas the remaining brain volume negatively correlated with the NHPSS. Following ROI parcellation, NHPSS outcome correlated with frontal, temporal, occipital, and middle white matter, as well as the internal capsule, and the superior temporal and middle temporal gyri, and the caudate nucleus. These results represent an important step in stroke translational research by demonstrating close similarities between the NHP stroke model and the clinical characteristics following a human stroke and illustrating significant areas that could represent targets for novel neuroprotective strategies.
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Conducta Animal , Isquemia Encefálica/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Recuperación de la Función , Accidente Cerebrovascular/diagnóstico por imagen , Animales , Encéfalo/patología , Isquemia Encefálica/patología , Isquemia Encefálica/psicología , Modelos Animales de Enfermedad , Sustancia Gris/diagnóstico por imagen , Sustancia Gris/patología , Procesamiento de Imagen Asistido por Computador , Estudios Longitudinales , Macaca fascicularis , Imagen por Resonancia Magnética , Masculino , Tamaño de los Órganos , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/psicología , Factores de Tiempo , Sustancia Blanca/diagnóstico por imagen , Sustancia Blanca/patologíaRESUMEN
Among sex steroid hormones, progesterone and estradiol have a wide diversity of physiological activities that target the nervous system. Not only are they carried by the blood stream, but also they are locally synthesized in the brain and for this reason, estradiol and progesterone are considered 'neurosteroids'. The physiological actions of both hormones range from brain development and neurotransmission to aging, illustrating the importance of a deep understanding of their mechanisms of action. In this review, we summarize key roles that estradiol and progesterone play in the brain. As numerous reports have confirmed a substantial neuroprotective role for estradiol in models of neurodegenerative disease, we focus this review on traumatic brain injury and stroke models. We describe updated data from receptor and signaling events triggered by both hormones, with an emphasis on the mechanisms that have been reported as 'rapid' or 'cytoplasmic actions'. Data showing the therapeutic effects of the hormones, used alone or in combination, are also summarized, with a focus on rodent models of middle cerebral artery occlusion (MCAO). Finally, we draw attention to evidence that neuroprotection by both hormones might be due to a combination of 'cytoplasmic' and 'nuclear' signaling.
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Isquemia Encefálica , Encéfalo/efectos de los fármacos , Hormonas Esteroides Gonadales/farmacología , Fármacos Neuroprotectores/farmacología , Animales , Lesiones Traumáticas del Encéfalo/complicaciones , Lesiones Traumáticas del Encéfalo/patología , Lesiones Traumáticas del Encéfalo/prevención & control , Isquemia Encefálica/complicaciones , Isquemia Encefálica/patología , Isquemia Encefálica/prevención & control , Modelos Animales de Enfermedad , Estradiol/farmacología , Humanos , Modelos Teóricos , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/prevención & control , Neuroprotección/efectos de los fármacos , Progesterona/farmacología , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/patología , Accidente Cerebrovascular/prevención & controlRESUMEN
Abstract White pepper (Piper nigrum L.) and long pepper (Piper longum L.) belong to family Piperaceae and are commonly used as household spices and traditional medicine worldwide, specifically in China and Southeast Asia. In Traditional Chinese Hui Medicine, these herbs are widely used for treatment of stroke. Our present study investigated effects of these herbs on inflammation in rat model with cerebral ischemia. After subjecting the rats to permanent middle cerebral artery occlusion (pMCAO) for 6 h, at doses of 100 and 200 mg/kg, dichloromethane fraction from white pepper and long pepper, respectively, was intragastrically administered once a day for seven consecutive days. Cerebral cortical and hippocampal tissues were collected after seven days. Superoxide dismutase, malonaldehyde, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 were measured by spectrophotometer. Phytochemical profile of dichloromethane fraction was determined through HPLC. Dichloromethane fraction exhibited anti-inflammatory activity by suppressing expression or production of IL-1β, IL-6, and TNF-α. By contrast, dichloromethane fraction showed activity against pMCAO injury by reducing oxygen-free radicals through increased superoxide dismutase activity and decreased malonaldehyde level. HPLC analysis revealed piperine as major component of dichloromethane fraction. These results show that dichloromethane fraction provides protection against cerebral ischemia. The possible mechanism is related to anti-inflammatory activity and reduction in oxygen-free radicals.
RESUMEN
Regulatory T cells (Tregs) inhibit the activation of the immune response which could down-regulate the systemic and focal activation observed during ischemic stroke. In fact, in animal models, Tregs infiltrate the infarcted brain and reduce the pro-inflammatory cytokine production and infarct volume, mainly in late stages of ischemia. Recently, an expansion and greater suppressive capacity of circulating Tregs after treatment with statins was observed, in addition to their cardio- and neuroprotective actions demonstrated previously. Thus, to determine whether Treg modulation mediated by statins can also be beneficial during stroke, cerebral ischemia was artificially induced in Wistar rats by transient middle cerebral artery occlusion (tMCAO) during 60 minutes with subsequent reperfusion for 7 days. Six hours after surgery, some animals were treated with atorvastatin (ATV, 10 mg/kg) or carboxymethylcellulose as vehicle at the same concentration every other day during 7 days. Some animals were sham operated as control group of surgery. Interestingly, ATV treatment prevented the development of infarct volume, reduced the neurological deficits, and the circulating and cervical lymph node CD25+FoxP3+ Treg population. Moreover, there was a reduction of glial cell activation, which correlated with decreased circulating Tregs. Remarkably, treatment with ATV induced an increase in the frequency of CD4+CD25+ T cells, in particular of those expressing CTLA-4, in brain samples. Together, these results suggest that ATV can modulate Tregs in peripheral tissue and favor their accumulation in the brain, where they can exert neuroprotective actions maybe by the reduction of glial cell activation.
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Atorvastatina/uso terapéutico , Encéfalo/efectos de los fármacos , Modelos Animales de Enfermedad , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Linfocitos T Reguladores/efectos de los fármacos , Animales , Atorvastatina/farmacología , Encéfalo/inmunología , Encéfalo/metabolismo , Infarto de la Arteria Cerebral Media/inmunología , Infarto de la Arteria Cerebral Media/metabolismo , Masculino , Ratas , Ratas Wistar , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismoRESUMEN
We developed a forced non-electric-shock running wheel (FNESRW) system that provides rats with high-intensity exercise training using automatic exercise training patterns that are controlled by a microcontroller. The proposed system successfully makes a breakthrough in the traditional motorized running wheel to allow rats to perform high-intensity training and to enable comparisons with the treadmill at the same exercise intensity without any electric shock. A polyvinyl chloride runway with a rough rubber surface was coated on the periphery of the wheel so as to permit automatic acceleration training, and which allowed the rats to run consistently at high speeds (30 m/min for 1 h). An animal ischemic stroke model was used to validate the proposed system. FNESRW, treadmill, control, and sham groups were studied. The FNESRW and treadmill groups underwent 3 weeks of endurance running training. After 3 weeks, the experiments of middle cerebral artery occlusion, the modified neurological severity score (mNSS), an inclined plane test, and triphenyltetrazolium chloride were performed to evaluate the effectiveness of the proposed platform. The proposed platform showed that enhancement of motor function, mNSS, and infarct volumes was significantly stronger in the FNESRW group than the control group (P<0.05) and similar to the treadmill group. The experimental data demonstrated that the proposed platform can be applied to test the benefit of exercise-preconditioning-induced neuroprotection using the animal stroke model. Additional advantages of the FNESRW system include stand-alone capability, independence of subjective human adjustment, and ease of use.
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Animales , Masculino , Prueba de Esfuerzo/métodos , Terapia por Ejercicio/métodos , Infarto de la Arteria Cerebral Media/prevención & control , Esfuerzo Físico , Condicionamiento Físico Animal/instrumentación , Calibración , Infarto Cerebral/patología , Infarto Cerebral/prevención & control , Modelos Animales de Enfermedad , Diseño de Equipo , Invenciones , Infarto de la Arteria Cerebral Media/patología , Resistencia Física , Distribución Aleatoria , Ratas Wistar , Índice de Severidad de la Enfermedad , Programas Informáticos , Factores de TiempoRESUMEN
We previously showed that JM-20, a novel 1,5-benzodiazepine fused to a dihydropyridine moiety, possessed an anxiolytic profile similar to diazepam and strong neuroprotective activity in different cell models relevant to cerebral ischemia. Here, we investigated whether JM-20 protects against ischemic neuronal damage in vitro and in vivo. The effects of JM-20 were evaluated on hippocampal slices subjected to oxygen and glucose deprivation (OGD). For in vivo studies, Wistar rats were subjected 90 min of middle cerebral artery occlusion (MCAo) and oral administration of JM-20 at 2, 4 and 8 mg/kg 1 h following reperfusion. Twenty-four hours after cerebral blood flow restoration, neurological deficits were scored, and the infarct volume, histopathological changes in cortex, number of hippocampal and striatal neurons, and glutamate/aspartate concentrations in the cerebrospinal fluid were measured. Susceptibility to brain mitochondrial swelling, membrane potential dissipation, H2O2 generation, cytochrome c release, Ca2+ accumulation, and morphological changes in the organelles were assessed 24 h post-ischemia. In vitro, JM-20 (1 and 10 µM) administered during reperfusion significantly reduced cell death in hippocampal slices subjected to OGD. In vivo, JM-20 treatment (4 and 8 mg/kg) significantly decreased neurological deficit scores, edema formation, total infarct volumes and histological alterations in different brain regions. JM-20 treatment also protected brain mitochondria from ischemic damage, most likely by preventing Ca2+ accumulation in organelles. Moreover, an 8-mg/kg JM-20 dose reduced glutamate and aspartate concentrations in cerebrospinal fluid and the deleterious effects of MCAo even when delivered 8 h after blood flow restoration. These results suggest that in rats, JM-20 is a robust neuroprotective agent against ischemia/reperfusion injury with a wide therapeutic window. Our findings support the further examination of potential clinical JM-20 use to treat acute ischemic stroke.
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Benzodiazepinas/farmacología , Isquemia Encefálica/tratamiento farmacológico , Aminoácidos Excitadores/metabolismo , Mitocondrias/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Niacina/análogos & derivados , Animales , Encéfalo/efectos de los fármacos , Encéfalo/patología , Encéfalo/fisiopatología , Isquemia Encefálica/patología , Isquemia Encefálica/fisiopatología , Muerte Celular/efectos de los fármacos , Muerte Celular/fisiología , Modelos Animales de Enfermedad , Glucosa/deficiencia , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Infarto de la Arteria Cerebral Media/fisiopatología , Masculino , Mitocondrias/patología , Mitocondrias/fisiología , Niacina/farmacología , Distribución Aleatoria , Ratas Wistar , Técnicas de Cultivo de TejidosRESUMEN
OBJECTIVES: Our study aimed to investigate the impact of fatigue on the severity of stroke and to explore the underlying mechanisms. METHODS: Fatigued male rats underwent middle cerebral artery occlusion and the infarcted brain area was determined. Then, coagulation parameters were assessed in the fatigued group and a control group. In addition, the level of fibrinogen was determined in rats deprived of sleep for various numbers of days. To study whether interleukin-6 was involved in fibrinogen synthesis during fatigue, we also measured levels of interleukin-6 in rats deprived of sleep for various numbers of days. Furthermore, brain injury by middle cerebral artery occlusion was measured in wild-type mice, interleukin-6-/- mice and wild-type mice treated with bezafibrate. RESULTS: More severe cerebral infarction was observed in the fatigued rats, resulting in an infarct ratio of 23.4%. The infarct ratio was significantly increased in the fatigued rats compared with that in the control group (8%, p<0.05). The level of fibrinogen was increased significantly in the fatigued rats compared with that in the control group. In addition, a marked reduction in fibrinogen level was observed in the fatigued interleukin-6-/- mice compared to their wild-type counterparts, whereas no difference was observed between fatigued wild-type mice and interleukin-6-/- rats treated with recombinant human interleukin-6. The reduction in brain injury due to middle cerebral artery occlusion during fatigue was observed in interleukin-6-/- mice and wild-type mice treated with bezafibrate. CONCLUSION: Fatigue could increase stroke severity and was associated with the interleukin-6-induced expression of fibrinogen. .