RESUMEN
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.
Asunto(s)
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: The aim of this study was to investigate the effects of oral administration of a novel benzodiazepine derivative, JM-20, on the neurological behavior of different rodent models, focusing on the GABAergic effect. We have also investigated the acute toxicity of oral administration of JM-20 in mice. METHODS: Mice or rats received oral administration of JM-20 at 2, 4, 8, and 10 mg/kg to evaluate the sedative/hypnotic, anxiolytic, and anticonvulsant effects, as well as the influence on the stereotyped behavior induced by amphetamine. Diazepam (DZP) was used as a positive control. In addition, the mice received a single oral JM-20 dose of 2000 mg/kg to evaluate the acute toxicity. RESULTS: In a dose-dependent manner, JM-20 (i) increased the number of crossings and decreased the number of rearings in the open-field test; (ii) decreased the aggressive behavior of socially-isolated mice; and (iii) increased the latency period for tonic seizure's onset and the percentage of survival of animals with seizures. Moreover, JM-20 increased the sleeping time induced by barbiturates and the time spent and the number of entries in the open arms of the elevated plus-maze test. In the JM-20 toxicity test, no mortality was observed and only minor signs of toxicity associated with sedation were detected. CONCLUSIONS: These results indicate that JM-20 has an anxiolytic profile similar to DZP and its dihydropyridine moiety did not appear to interfere with the GABAergic activity associated with benzodiazepine. Furthermore, JM-20 did not show significant acute toxic effects in mice.
Asunto(s)
Ansiolíticos/farmacología , Conducta Animal/efectos de los fármacos , Benzodiazepinas/química , Dihidropiridinas/química , Hipnóticos y Sedantes/farmacología , Niacina/análogos & derivados , Administración Oral , Animales , Ansiolíticos/administración & dosificación , Ansiolíticos/efectos adversos , Ansiolíticos/toxicidad , Anticonvulsivantes/administración & dosificación , Anticonvulsivantes/efectos adversos , Anticonvulsivantes/farmacología , Anticonvulsivantes/toxicidad , Benzodiazepinas/síntesis química , Benzodiazepinas/farmacología , Benzodiazepinas/toxicidad , Diazepam/farmacología , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Interacciones Farmacológicas , Femenino , Hipnóticos y Sedantes/administración & dosificación , Hipnóticos y Sedantes/efectos adversos , Hipnóticos y Sedantes/toxicidad , Masculino , Ratones , Niacina/síntesis química , Niacina/química , Niacina/farmacología , Niacina/toxicidad , RatasRESUMEN
The most common cause of stroke is cerebral ischemia, where blood flow to the brain is interrupted due to a thrombus in a major cerebral artery. Currently, the only therapeutic approach available is thrombolysis. A more recent approach that has started to gain attention is neuroprotection, the ability to prevent neuronal death and enhance endogenous protective mechanisms. Several studies have shown the neuroprotective action of Erythropoietin (EPO). A potential problem in the use of EPO for neurodegenerative disorders is the undesirable erythropoietic side effects. In this context, investigations have been focused to develop derivatives of EPO lacking erythropoietic activity but retaining neuroprotective potential. Low sialic acid-containing EPO (Neuro EPO) is very similar to the one that occurs in the mammalian brain and is rapidly degraded by the liver. Similar neuroprotective effects had been observed with neuro EPO, original recombinant human EPO and EPO variants in ischemia models. Intranasal route could be safe and hematological side effects could be avoided. Neuro EPO that constitutes a new agent has retained the neuroprotective effects without stimulating the EPOR in the bone marrow and can therefore be used without increasing the hematocrit. This review gives a brief introduction to the no hematopoietic effects of EPO, the evidence of neuroprotective effect, the alternatives for obtaining an EPO derivate without hematological side effects and discusses the advantages of nasal administration of Neuro EPO for neuroprotective stroke treatment.