Study of Cerebellar Tissue Following Induction of Aging in Mice By Di-Galactose / Estudio del Tejido Cerebeloso tras la Inducción del Envejecimiento en Ratones por D-Galactosa

SUMMARY: The cerebellum is a crucial area of the hindbrain that plays an essential role in balancing, excitement control, and subtle and accurate functions. Studies have shown that long-term use of D-galactose in mice, as with the symptoms of aging, causes morphological and functional disorders in the brain. This study was performed to evaluate the changes in the cerebellum cortex tissue and the measurement of reactive oxygen species (ROS) in the cerebellum following the induction of aging in mice by D-galactose. Accordingly, subjects were randomly assigned into two groups: Normal saline group and Aging group (D-galactose). To create an aging model, D- galactose, and saline solution (sodium chloride 0.9 %) were used. After completing the preparation and passage of the tissue, the cerebellum specimens were cut in 5 microns thickness and then stained with hematoxylin-eosin stain and finally examined under a Nikon microscope. Quantitative variables were analyzed by SPSS software using T-test. In the observations of cerebellum tissue samples, in the aged induced group by D-galactose, the most changes were observed in the Neuron purkinjense (Purkinje cells) layer. In the observations of the cerebellum tissue samples of aging group induced by D-galactose, the most changes were observed in the Neuron purkinjense, and the arrangement and placement of these cells were disorientated. The nucleus positioning was not central, and the Neuron purkinjense induced by aging were seen in different morphological forms. Necrosis, Chromatolysis, and Pyknosis were found. Based on the results, D-galactose (induction of aging) causes pathological changes in the cerebellar cortex, especially in the Neuron purkinjense layer.

El cerebelo es un área crucial del rombencéfalo que desempeña un papel esencial en el equilibrio, el control de la excitación y las funciones sutiles y precisas. Los estudios han demostrado que el uso a largo plazo de D-galactosa en ratones, al igual que con los síntomas del envejecimiento, provoca trastornos morfológicos y funcionales en el cerebro. Este estudio se realizó para evaluar los cambios en el tejido de la corteza del cerebelo y la medición de especies reactivas de oxígeno (ROS) en el cerebelo luego de la inducción del envejecimiento en ratones por D-galactosa. En consecuencia, los sujetos fueron asignados aleatoriamente a dos grupos: grupo de solución salina normal y grupo de envejecimiento (D-galactosa). Para crear un modelo de envejecimiento, se utilizaron D-galactosa y solución salina (cloruro de sodio al 0,9 %). Después de completar la preparación y el paso del tejido, las muestras de cerebelo se cortaron en un grosor de 5 µm y luego se tiñeron con tinción de hematoxilina-eosina y finalmente se examinaron bajo un microscopio Nikon. Las variables cuantitativas se analizaron mediante el software SPSS utilizando la prueba T. En las observaciones de muestras de tejido de cerebelo, en el grupo envejecido inducido por D-galactosa, la mayoría de los cambios se observaron en la capa de neuronas purkinjenses (células de Purkinje). En las observaciones de las muestras de tejido del cerebelo del grupo de envejecimiento inducidas por D-galactosa, la mayoría de los cambios se observaron en las neuronas purkinjenses, y la disposición y ubicación de estas células estaban desorientadas. El posicionamiento del núcleo no era central y las neuronas purkinjenses inducidas por el envejecimiento se observaban en diferentes formas morfológicas. Se encontró necrosis, cromatólisis y picnosis. Según los resultados, la D-galactosa (inducción del envejecimiento) provoca cambios patológicos en la corteza cerebelosa, especialmente en la capa de neuronas purkinjenses.

Toxoplasma gondii infection damages the perineuronal nets in a murine model

BACKGROUND Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host's behavior. OBJECTIVES In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.

Melissa officinalis acidic fraction protects cultured cerebellar granule neurons against beta amyloid-induced apoptosis and oxidative stress

Objective: Extracellular deposition of the beta-amyloid [A beta] peptide, which is the main finding in the pathophysiology of Alzheimer's disease [AD], leads to oxidative damage and apoptosis in neurons. Melissa officinalis [M. officinalis] is a medicinal plant from the Lamiaceae family that has neuroprotective activity. In the present study we have investigated the protective effect of the acidic fraction of M. officinalis on A beta-induced oxidative stress and apoptosis in cultured cerebellar granule neurons [CGN]. Additionally, we investigated a possible role of the nicotinic receptor

Materials and Methods: This study was an in vitro experimental study performed on mice cultured CGNs. CGNs were pre-incubated with different concentrations of the acidic fraction of M. officinalis for 24 hours, followed by incubation with A beta for an additional 48 hours. CGNs were also pre-incubated with the acidic fraction of M. officinalis and mecamylamin, followed by incubation with A beta. We used the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assay to measure cell viability. Acetylcholinesterase [AChE] activity, reactive oxygen species [ROS] production, lipidperoxidation, and caspase-3 activity were measured after incubation. Hochst/annexin V- fluorescein isothiocyanate [FITC]/propidium iodide [PI] staining was performed to detect apoptotic cells

Results: The acidic fraction could protect CGNs from A beta-induced cytotoxicity. Mecamylamine did not abolish the protective effect of the acidic fraction. AChE activity, ROS production, lipid peroxidation, and caspase-3 activity increased after A beta incubation. Pre-incubation with the acidic fraction of M. officinalis ameliorated these factors and decreased the number of apoptotic cells

Conclusion: Our results indicated that the protective effect of the acidic fraction of M. officinalis was not mediated through nicotinic receptors. This fraction could protect CGNs through antioxidant and anti-apoptotic activities

Perioperative myocardial infarction in patients undergoing myocardial revascularization surgery / Infarto do miocárdio perioperatório em pacientes submetidos à cirurgia de revascularização miocárdica

Introduction: Perioperative myocardial infarction adversely affects the prognosis of patients undergoing coronary artery bypass graft and its diagnosis was hampered by numerous difficulties, because the pathophysiology is different from the traditional instability atherosclerotic and the clinical difficulty to be characterized. Objective: To identify the frequency of perioperative myocardial infarction and its outcome in patients undergoing coronary artery bypass graft. Methods: Retrospective cohort study performed in a tertiary hospital specialized in cardiology, from May 01, 2011 to April 30, 2012, which included all records containing coronary artery bypass graft records. To confirm the diagnosis of perioperative myocardial infarction criteria, the Third Universal Definition of Myocardial Infarction was used. Results: We analyzed 116 cases. Perioperative myocardial infarction was diagnosed in 28 patients (24.1%). Number of grafts and use and cardiopulmonary bypass time were associated with this diagnosis and the mean age was significantly higher in this group. The diagnostic criteria elevated troponin I, which was positive in 99.1% of cases regardless of diagnosis of perioperative myocardial infarction. No significant difference was found between length of hospital stay and intensive care unit in patients with and without this complication, however patients with perioperative myocardial infarction progressed with worse left ventricular function and more death cases. Conclusion: The frequency of perioperative myocardial infarction found in this study was considered high and as a consequence the same observed average higher troponin I, more cases of worsening left ventricular function and death. .

Introdução: O infarto do miocárdio perioperatório afeta negativamente o prognóstico dos pacientes submetidos à cirurgia de revascularização do miocárdio e seu diagnóstico esbarra em inúmeras dificuldades, pois a fisiopatologia é diferente da tradicional instabilidade aterosclerótica e o quadro clínico de difícil caracterização. Objetivo: Identificar a frequência de infarto do miocárdio perioperatório e seu desfecho em pacientes submetidos à cirurgia de revascularização do miocárdio. Métodos: Coorte retrospectiva realizada em hospital terciário especializado em cardiologia, de 1 de maio de 2011 a 30 de abril de 2012, que incluiu todos os prontuários contendo registros de cirurgia de revascularização do miocárdio. Para confirmação diagnóstica do infarto do miocárdio perioperatório, foram utilizados os critérios da Third Universal Definition of Myocardial Infarction Resultados: Foram analisados 116 casos. Foi diagnosticado infarto do miocárdio perioperatório em 28 pacientes (24,1%). Número de enxertos e utilização e tempo de circulação extracorpórea foram fatores associados a este diagnóstico e a média de idade foi significativamente mais elevada neste grupo. O critério diagnóstico elevação de troponina I foi positivo em 99,1% dos casos, independentemente do diagnóstico de infarto do miocárdio perioperatório. Não foi encontrada diferença significativa entre tempo de internação hospitalar e em unidade de terapia intensiva nos grupos com e sem esta complicação, porém pacientes com infarto do miocárdio perioperatório evoluíram com pior função ventricular esquerda e mais casos de óbito. Conclusão: A frequência de infarto do miocárdio perioperatório encontrada neste trabalho foi considerada alta e como consequência do mesmo observou-se média mais elevada de troponina I, mais casos de piora da função ventricular esquerda e óbito. .

Confocal laser scanning microscopy and immunohistochemistry of cerebellar Lugaro cells

The present paper shows by means of confocal laser scanning microscopy the immunoreactivity of rat cerebellar Lugaro cells for calbindin, synapsin-I, PSD-95, GluR1, CaMKII alpha, and N-cadherin. Lugaro cells were easily characterized by their location beneath Purkinje cells. Calbindin revealed immunoreactivity in the cell body, and the axonal and dendritic processes. Synapsin-I labelled the presynaptic endings on Lugaro cells. Synapsin-I and PSD-95 immunoreactivity demonstrated the localization of presynaptic and postsynaptic endings surrounding cell soma, corresponding to afferent extrinsic and intrinsic cerebellar fibers. GluR1 immunoreactivity of the soma and cell processes indicates that Lugaro cells have functional ionotropic glutamate receptors that regulate calcium levels. CaMKII alpha immunoreactivity of L ugaro cell soma and processes suggest its participation as a molecular switch for long-term information storage, and serving as a molecular basis of long-term synaptic memory. N-cadherin immunoreactivity was correlated with somato-somatic and somato-dendritic junctions between Lugaro cells and their synaptic connections.

Immunohistochemistry of GluR1 subunits of AMPA receptors of rat cerebellar nerve cells

The localization of GluR1 subunits of ionotropic glutamate receptors in the glial cells and inhibitory neurons of cerebellar cortex and their association with the climbing and parallel fibers, and basket cell axons were studied. Samples of P14 and P21 rat cerebellar cortex were exposed to a specific antibody against GluR1 subunit(s) ofAMPA receptors and were examined with confocal laser scanning microscopy. GluR1 strong immunoreactivity was confined to Purkinje cell and the molecular layer. Weak GluR1 immunoreactivity was observed surrounding some Golgi cells in the granule cell layer. Intense GluR1 immunoreactivity was localized around Purkinje, basket, and stellate cells. Purkinje cells expressed strong GluR1 immunoreactivity surrounding the cell body, primary dendritic trunk and secondary and tertiary spiny den dritic branches. Marked immunofluorescent staining was also detected in the Bergmann glial fibers at the level of middle and outer third molecular layer. Positive immunofluorescence staining was also observed surrounding basket and stellate cells, and in the capillary wall. These findings suggest the specific localization of GluR1 subunits ofAMPA receptors in Bergmann glial cells, inhibitory cerebellar neurons, and the associated excitatory glutamatergic circuits formed by climbing and parallel fibers, and by the inhibitory basket cell axons.

Effects of deltamethrin on granule cell migration during postnatal development of rat cerebellum.

Deltamethrin (DLT; 0.7mg/kg/body wt/day, i.p., dissolved in propylene glycol) administration during postnatal days 913 in Albino rat pups, resulted in a delayed appearance of radial glial fibers, that guide the migration of granule cells. Moreover, the radial glial fibers in the DLT-treated pups were disorganized, hypertrophied and heavily stained. Thus, it is being proposed that although after exposure to DLT the neuronal proliferation occurs at normal rate, the neuronal migration along the stumpy and crumpled radial fibers hamper the journey of the healthy neurons to their proper destination.

Neurotoxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin in cerebellar granule cells

An environmental pollutant, tetrachloro dibenzo dioxin (TCDD) is known to illicit the cognitive disability and motor dysfunction in the developing brain. TCDD induced effects leading to neurodevelopmental and neurobehavioral deficit may have been defined, however underlying molecular mechanism and possible intracellular targets remain to be elucidated. In this study, we attempted to analyze TCDD-induced neurotoxic effects in the granule cells from cerebellum where certain cognitive abilities and motor function command are known to be excuted. [3H]PDBu, (phorbol 12,13-dibutyrate) binding assay indicated that TCDD induced a dose-dependent increase of total PKC activity and its induction was the aryl hydrocarbon receptor (AhR) dependent and N-methyl-D-aspartate receptor (NMDAR) independent. TCDD also caused the translocation of both PKC-alpha and -epsilon in a dose-dependent manner but associated with different receptors; PKC-alpha via AhR but not PKC-epsilon indicating an isozyme-specific pattern of the induction. Increase of the ROS formation was also observed in the cells treated with TCDD in a dose-dependent and an AhR-dependent manner. The treatment of the cells with the diamino dicyano-bis(2-aminophenylthio) butadiene (U0126, MEK-1/2 inhibitor), dizocilpine maleate (MK-801, non-competitive N-methyl-D-aspartate glutamate receptor antagonist) and vitamin E attenuated the TCDD-induced ROS production indicating that TCDD-induced ROS formation may be associated with activation of ERK-1/2 in the MAP kinase pathway or the NMDA receptor. TCDD also increased [Ca2+]i, which is associated with ROS formation and PKC activation in the cerebellar granule cells. It is suggested that TCDD activates the NMDA receptor, which may induce a sustained increase of [Ca2+]i in neurons followed by the ROS formation. Our findings may contribute to understanding the mechanism of TCDD-related neurotoxicity, thereby improving the health risk assessment of neurotoxic compounds in humans.

Distribution of Adenoviral Vector in Brain after Intravenous Administration

The delivery of transgenes to the central nervous system (CNS) can be a valuable tool to treat CNS diseases. Various systems for the delivery to the CNS have been developed; vascular delivery of viral vectors being most recent. Here, we investigated gene transfer to the CNS by intravenous injection of recombinant adenoviral vectors, containing green fluorescence protein (GFP) as a reporter gene. Expression of GFP was first observed 6 days after the gene transfer, peaked at 14 days, and almost diminished after 28 days. The observed expression of GFP in the CNS was highly localized to hippocampal CA regions of cerebral neocortex, inferior colliculus of midbrain, and granular cell and Purkinje cell layers of cerebellum. It is concluded that intravenous delivery of adenoviral vectors can be used for gene delivery to the CNS, and hence the technique could be beneficial to gene therapy.

Expression of PSD95 in the Rat Sciatic Nerve

This study was designed to elucidate the existence of PSD95 in the rat sciatic nerve. Immunohistochemical stains of cryosection and teased fiber of sciatic nerves were performed with goat polyclonal antibody against PSD95. Western blot analysis was also accomplished with the same antibody. We got an interesting result that the rat sciatic nerve obviously showed PSD95 immunoreactivity especially in the nodal and paranodal regions, and we also identified a distinct band of PSD95 by western blot. These results suggest PSD95 exists in the sciatic nerve as well as it does in the central nervous system. We suppose PSD95 may have some important roles in ion channel clustering, junctional plasticity and signal transduction in the peripheral nerves as well.

Immunohistochemistry of Voltage-Gated Calcium Channel alpha1B Subunit in Mouse Cerebellum

Secretion of neurotransmitters is initiated by voltagegated calcium influx through presynaptic, voltage- gated N-type calcium channels. However, little is known about their cellular distribution in the mouse cerebellum. In the cerebellum, alpha1B immunoreactivity is found mainly on the cell bodies of all Purkinje cells. In addition, the immunoreactivity was detected on a subset of Purkinje cell dendrites, clustered to form a parasagittal array of bands. In the anterior lobe vermis, immunoreactive Purkinje cell dendrites form narrow stripes separated by broad bands of unstained dendrites. Moving caudally through the vermis, these stripes become thicker as a larger fraction of the Purkinje cell dendrites become immunoreactive. This localization study of the alpha1B pore-forming subunits in mouse cerebellum may guide future investigations of the role of calcium channels in neurological pathways.

Deterioro cerebeloso inducido por aislamiento social temprano: estudio morfológico e inmunocitoquímico / Cerebellar impairment induced by early social isolation: a morphological and immunocytochemical study

En el presente trabajo se utiliza el modelo de aislamiento social en animales a objeto de estudiar el efecto que produce las experiencias tempranas adversas sobre el desarrollo morfofuncional de la corteza cerebelosa. Se utilizaron 103 ratas de la cepa Sprague-Dawley de 18 días de vida, las cuales fueron sepradas en dos grupos de estudio: (a) control (SC; 3- 4 ratas por jaula y (b) aislado (IC); estas últimas se colocaron en comportamientos individuales hasta los 32 días de edad (P32). En esta etapa, el 50 por ciento de los animales IC y SC fueron sacrificadas para su estudio neural; el resto de las ratas del grupo IC fue retirado de sus compartimientos individuales y reubicados en su entorno social normal hasta el día P62, realizándose el análisis neural respectivo. En ambas fases ontogenéticas (P32 y P62) se estudió el desarrollo dendrítico y la expresión de calbindina-D28k (CBD) en células de Purkinje vermianas. Los resultados obtenidos mostraron que la deprivación social y sensoriomotriz temprana altera el crecimiento dendríco en estrecha relación con una disminución del contenido intracelular de CBD. Además, la interacción social post-deprivación sólo logró recuperar la expresión de CBD, permaneciendo el deterioro estructural. Estos resultados indican que las experiencias postnatales adversas alteran el desarrollo morfológico y funcional de las neuronas de Purkinje vermianas cuando se emplea el modelo de aislamiento social

Cerebellar granule cell membranes and glutamate mediates transactivation of glutamine synthetase promoter.

Potential region of glutamine synthetase promoter driving astrocyte-specific transactivation, mediated by cerebellar granule cell membrane and glutamate has been identified by deletion analysis of promoter and transient transfection. The promoter region from -420 to -765 was found to be potentially important for this transactivation. These results provided further evidence for importance of neuronal-glial and glutamate-glial interactions in regulation of glial gene expression.