Áreas exofocales de lesión a mediano y largo término post-isquemia cerebral / Exofocal areas of medium- and long-term injury after cerebral ischemia

La isquemia cerebral es el tipo de accidente cerebrovascular más común, generando altas tasas de mortalidad y morbilidad a nivel mundial. El entendimiento de la fisiopatología de la lesión cerebral ha requerido de la implementación de modelos experimentales que permitan evaluar los fenómenos celulares, sobre todo aquellos a largo plazo. Por tal razón, el objetivo del presente trabajo fue evaluar las áreas exofocales a un mes y cuatro meses post-isquemia cerebral en un modelo experimental. Ratas Wistar fueron sometidas a una isquemia focal transitoria (t-MCAo) y un grupo fueron sacrificados al mes y otro grupo a los cuatro meses post-isquemia para su posterior análisis histológico. Los cortes fueron teñidos con Nissl y se realizó inmunohistoquímica de la proteína Tau. Nuestros resultados muestran tres áreas de lesión exofocal tanto al mes como a los cuatro meses post-isquemia: el giro dentado, la amígdala y el tálamo. Estas regiones se han asociado al control emocional, lo cual sugiere que a largo término post-isquemia se tengan en cuenta hallazgos clínicos que evalúen cambios emocionales en los pacientes que han sufrido un evento isquémico cerebral.

Cerebral ischemia is the most common type of stroke, which generates high mortality and morbidity rates worldwide. The understanding of the pathophysiology of brain injury has required the implementation of experimental models that allow the evaluation of cellular phenomena, especially those in the long-term. For this reason, the objective of the present work was to evaluate the exofocal areas at one month and four months after cerebral ischemia. Wistar rats were subjected to transient focal ischemia (t-MCAo) and one group was sacrificed one month and another group at four months' post-ischemia for subsequent histological analysis. The cuts were stained with Nissl and immunohistochemistry of the Tau protein was performed. Our results show three areas of exofocal lesion both one month and four months' post-ischemia: the thalamus, the dentate gyrus, and the amygdala. These regions have been associated with emotional control, which suggests that in the long-term post-ischemia clinical findings that evaluate emotional changes in patients who have suffered a cerebral ischemic event should be considered.

Hippocampal neuronal apoptosis in rat offspring due to gestational diabetes / Apoptosis neuronal del hipocampo en crías de ratas debido a la diabetes gestacional

Gestational diabetes mellitus (GDM) defined as impaired glucose tolerance affects approximately 6 % of all pregnant women who have never before had diabetes, but who do have high blood glucose levels during pregnancy. This study was done to evaluate the apoptosis in the neuronal cells in the CA1, CA2 and CA3 subfields of hippocampus and dentate gyrus in offspring of gestational diabetes at the 7, 21 and 28 d in postnatal rats. Thirty Wistar rat dams were randomly allocated in control and diabetic group. Dams in diabetic group were received 40 mg/kg/BW of streptozotocin at the first day of gestation and control groups received an equivalent volume normal saline injection intraperitoneally (IP). Six offspring of GDM and control dams, at the 7, 21, 28 postnatal day were randomly were sacrificed quickly with anesthesia. The coronal sections of brain serially collected. The apoptosis neurons were evaluated with TUNEL Assay. In the CA1, the number of apoptotic cells in 7, 21 and 28 d of postnatal life were significantly increased in GDM compared to controls (P<0.001). In the CA2, CA3 the number of apoptotic cells in 7, 21 and 28 d age-old offspring were significantly increased in GDM compared to controls (P<0.001). In the dentate gyrus, the number of apoptotic cells in 7, 21 and 28 d of postnatal life were significantly increased in GDM compared to controls (P<0.01). This study showed that the uncontrolled gestational diabetes significantly increases neuronal apoptosis in hippocampal and dentate gyrus in rat offspring.

La diabetes mellitus gestacional (DMG) se define como la intolerancia a la glucosa que afecta aproximadamente al 6 % de todas las mujeres embarazadas que nunca han tenido diabetes, pero que sí tienen niveles de glucosa en la sangre elevados durante el embarazo. El objetivo de este estudio fue evaluar la apoptosis de células neuronales en CA1, CA2 y CA3, subcampos del hipocampo y el giro dentado, en las crías de ratas con diabetes gestacional en los días 7, 21 y 28 luego del nacimiento. Se utilizaron 30 ratas Wistar asignadas aleatoriamente en grupos control y diabético (GDM). Se administró al grupo diabético 40 mg/kg de peso corporal de estreptozotocina en el primer día de gestación y el grupo control recibió un volumen equivalente de solución salina normal por inyección vía intraperitoneal. Seis crías de los grupos GDM y control fueron seleccionadas aleatoriamente y sacrificadas bajo anestesia los días 7, 21, 28. Se tomaron secciones seriales coronales del cerebro. La apoptosis neuronal se evaluó mediante ensayo TUNEL. En el CA1, el número de células apoptóticas a los 7, 21 y 28 d se incrementó significativamente en el grupo GDM en comparación con los controles (P <0.001). En el CA2 y CA3 el número de células apoptóticas en los días 7, 21 y 28 también se incrementó significativamente en GDM en comparación con los controles (P <0,001). En el giro dentado, el número de células apoptóticas en los días 7, 21 y 28 se incrementó significativamente en GDM en comparación con los controles (P <0,01). Este estudio mostró que la diabetes gestacional no controlada aumenta significativamente la apoptosis neuronal en el hipocampo y el giro dentado en las crías de las ratas.

Dentate gyrus changes in an Alzheimer-induced model in adult male albino rats and the possible protection by ginger: Histological and immunohistochemical study

Alzheimer's disease [AD] is the most prevalent neurodegenerative disorder, and its incidence is increasing markedly worldwide. It causes progressive cognitive decline and is the most common cause of dementia in the elderly. It has been proven that prolonged aluminum exposure induces Alzheimer-like histopathological changes and hence aluminum was used experimentally to produce an animal model of AD. Ginger has been shown to inhibit and even reverse the deposition of amyloid plaques, which are considered one of the hallmarks of AD. The present study was carried out to determine the histological changes in the dentate gyrus of the hippocampus in an Alzheimer-induced model and investigate the possible ameliorating effect of ginger. Twenty-one adult male albino rats were divided equally into three groups: the control group; the Alzheimer-induced model group, which received aluminum chloride [300 mg/kg/day orally] for 1 month; and the ginger-treated group, which received ginger [200 mg/kg/day orally] concomitant with aluminum chloride at the same dose and for the same period as that of the previous group. Temporal lobes of the cerebral cortex were processed with H and E, toluidine blue, silver, and Congo red stains. In addition, inducible nitric oxide synthase expression was assayed by immunohistochemistry. Chronic administration of aluminum chloride induced Alzheimer-like changes in the dentate gyrus, such as distortion of the granular cell layer, increased number of immature neurons, and disturbed arrangement and reduction in the number of pyramidal cells, which appeared with darkly stained pyknotic nuclei. Fine argentophilic neurofibrillary tangles and amyloid plaques were detected, in addition to increased intensity of inducible nitric oxide synthase expression in the granular cell layer. Ginger administration ameliorated the previous histological changes. The findings proved that chronic administration of ginger significantly improved the neurodegenerative changes induced in the Alzheimer model. Hence, it is advisable to drink ginger juice, especially the elderly, who are more susceptible to AD

Alteration of dentate gyrus astrocytes in diabetic rats: protective role of urtica dioica / Alteración de los astrocitos del giro dentado en ratas diabéticas: rol protector de urtica dioica

Diabetes mellitus can cause astrocytes alterations in the central nervous system. Urtica dioica (Nettle) is among several species listed for their use against diabetes in folk medicine. Therefore, this study was done to evaluate the protective effect of Urtica dioica on astrocytes density of the dentate gyrus in STZ induced diabetic rats. In this experimental study, 21 male albino Wistar rats were randomly allocated equally into normal, diabetic and protective (nettle treated diabetic) groups. Hyperglycemia was induced by streptozotocin (80 mg/kg) in the animals of diabetic and treatment groups. Before induction of diabetes in animals, animals in protective group received hydroalcoholic extract of Urtica dioica (100 mg/kg/BW /day) for five days intraperitoneally. Four weeks after induction of diabetes, animals were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with PTAH stain. The area densities of the astrocytes were measured and compared in the three groups (p < 0.05). The number of astrocytes in DG area of controls was 17.72+/-6.7. The density of astrocytes increased in diabetic (24.26+/-9.5) in comparison with controls. The density in the nettle treated rats (23.17+/-5.8) was lower than diabetic rats. This study showed that the administration of U. dioica extract before induction of diabetes can not significantly help compensate for astrocytes in the dentate gyrus of treated rats.

La diabetes mellitus puede provocar alteraciones de los astrocitos en el sistema nervioso central. La Urtica dioica (ortiga) es una de varias especies incluidas para su uso contra la diabetes en la medicina popular. Este estudio se realizó para evaluar el efecto protector de la Urtica dioica sobre la densidad de los astrocitos en el giro dentado en ratas con diabetes inducida por STZ. En este estudio experimental 21 ratas albinas Wistar fueron asignadas al azar equitativamente en grupos normal, diabético y protegido (diabéticos tratados con ortiga). La hiperglicemia fue inducida por estreptozotocina (80 mg/kg) en los grupos de animales diabéticos y en tratamiento protector. Previo a la inducción diabética, los animales del grupo protegido recibieron, por vía intraperitoneal, extracto hidroalcohólico de Urtica dioica (100 mg/kg/peso corporal/día) durante cinco días . Cuatro semanas después de la inducción de la diabetes, los animales fueron sacrificados y se tomaron secciones coronales de la formación del hipocampo dorsal de los hemisferios cerebrales derechos y se tiñeron con tinción PTAH. La densidad de área de los astrocitos fue medida y comparada en los tres grupos (p<0,05). El número de astrocitos en el área del giro dentado en los controles fue 17,72+/-6,7. La densidad de los astrocitos aumentó con la diabetes (24,26+/-9,5) en comparación con los controles. La densidad en las ratas tratadas con ortiga (23,17+/-5,8) fue menor que las ratas diabéticas. Este estudio demostró que la administración del extracto de U. dioica antes de la inducción diabética no ayuda significativamente a la compensación de los astrocitos en el giro dentados de las ratas tratadas.

Morphometric investigation of neurons in the hippocampal CA1, CA3 areas and dentate gyrus in a rat model of sepsis / Investigación morfométrica de neuronas en las áreas hipocampales CA1, CA3 y giro dentado en un modelo de sepsis en rata

Approximately, half of the patients with progressive sepsis develop encephalopathy, but there is scarce knowledge onto question that how the sepsis associated encephalopathy contributes brain dysfunction. Hippocampus is one of the most vulnerable regions during experimental sepsis. In the present study, effects of sepsis on the neuronal density and morphology in CA1, CA3 and DG areas were investigated in a rat model of intraperitoneal sepsis. Twenty-four Wistar rats were divided into three different groups: faecal peritonitis group, sham-operated and un-operated control groups. Pyramidal neuron volume density was significantly higher in CA1 area of the faecal peritonitis group compared to both un-operated (p<0.05) and sham-operated (p<0.05) groups. Pyramidal neuron volume density was also significantly higher in CA3 area of the faecal peritonitis group compared to both un-operated (p<0.05) and sham-operated (p<0.05) groups. Mean nuclear diameter of pyramidal neurons in CA1 area of the faecal peritonitis group was significantly lower (p<0.05) compared to un-operated control group. Dark, shrunken neurons were frequently observed and neuroglial cells appeared to be prevalent in the faecal peritonitis group compared to control groups. These results collectively suggest that intraperitoneal sepsis does not initiate cell death in the early stages of sepsis, although morphological signs of neurodegeneration start to appear.

Aproximadamente, la mitad de los pacientes con sepsis progresiva desarrollan encefalopatía, pero hay escaso conocimiento en cuestión de como la sepsis asociada con encefalopatía contribuye a la disfunción cerebral. El hipocampo es una de las regiones más vulnerables durante la sepsis experimental. En el presente estudio, fueron analizados los efectos de la sepsis sobre la densidad neuronal y la morfología en las áreas CA1, CA3 y giro dentado en un modelo de sepsis intraperitoneal en rata. Veinticuatro ratas Wistar se dividieron en tres grupos diferentes: grupo de peritonitis fecal, operación simulada y control no operado. La densidad del volúmen piramidal fue significativamente mayor en el área CA1 del grupo con peritonitis fecal en comparación con los grupos no operados (p<0,05) y la operación simulada (p<0,05). La densidad de volumen de las neuronas piramidales fue significativamente mayor en el área CA3 del grupo peritonitis fecal en comparación con los no operado (p<0,05) y la operación simulada (p<0,05). El diámetro promedio nuclear de las neuronas piramidales en la zona CA1 del grupo de peritonitis fecal fue significativamente menor (p<0,05) en comparación con el grupo de control no operado. Las neuronas fueron observadas con frecuencia reducidas y las células neurogliales parecen ser frecuentes en el grupo de peritonitis fecal en comparación con grupos de control. Estos resultados en conjunto sugieren que la sepsis intraperitoneal no inicia la muerte celular en las primeras etapas de la sepsis, aunque los signos morfológicos de la neurodegeneración empiezan a aparecer.

Estudo qualitativo da formação hipocampal de animais hipertensos com epilepsia / Qualitative study of hippocampal formation in hypertensive rats with epilepsy

O objetivo deste estudo foi avaliar qualitativamente o hipocampo e o giro dentado de ratos espontaneamente hipertensos (SHR) com epilepsia. MÉTODO: Os animais foram divididos em 4 grupos: Wistar controle, Wistar com epilepsia, SHR controle e SHR com epilepsia. Para indução da epilepsia, utilizamos o modelo da pilocarpina. Após os animais apresentarem crises espontâneas e recorrentes, o tecido cerebral dos animais foi encaminhado para análise histológica através dos métodos de Nissl e neo-Timm. RESULTADOS: Nos animais Wistar e SHR controle submetidos à coloração de Nissl observamos a manutenção das camadas celulares da formação hipocampal. Nos animais Wistar com epilepsia verificamos intensa morte neuronal na região CA1 e CA3 do hipocampo e no hilo do giro dentado. Nos animais SHR com epilepsia verificou-se a presença de atrofia hipocampal com dilatação do sistema ventricular. A coloração de neo-Timm revelou a presença de brotamento supragranular em todos os animais com epilepsia. CONCLUSÃO: Foram encontradas alterações neuropatológicas na citoarquitetura hipocampal nos animais Wistar com epilepsia e SHR com epilepsia, demonstrando que a epilepsia isoladamente ou associadamente à hipertensão são capazes de causar destruição neuronal.