Assessment of serotonergic system in formation of memory and learning / Avaliação do sistema serotonérgico na formação de memória e aprendizagem

We evaluated the involvement of the serotonergic system on memory formation and learning processes in healthy adults Wistar rats. Fifty-seven rats of 5 groups had one serotonergic nuclei damaged by an electric current. Electrolytic lesion was carried out using a continuous current of 2mA during two seconds by stereotactic surgery. Animals were submitted to learning and memory tests. Rats presented different responses in the memory tests depending on the serotonergic nucleus involved. Both explicit and implicit memory may be affected after lesion although some groups showed significant difference and others did not. A damage in the serotonergic nucleus was able to cause impairment in the memory of Wistar. The formation of implicit and explicit memory is impaired after injury in some serotonergic nuclei.(AU)

Avaliar a participação do sistema serotoninérgico em processos de formação de memória e aprendizagem em ratos Wistar adultos saudáveis. Cinquenta e sete ratos de 5 grupos tinham um núcleo serotoninérgico danificado por uma corrente elétrica. A lesão eletrolítica foi realizada utilizando uma corrente contínua de 2 mA durante dois segundos por cirurgia estereotáxica. Os animais foram submetidos a testes de aprendizagem e memória. Os ratos apresentaram respostas diferentes nos testes de memória, dependendo do núcleo serotoninérgica envolvido. A memória explícita e implícita pode ser afetada após a lesão, embora alguns grupos apresentaram diferença significativa e outros não. A lesão no núcleo serotoninérgico foi capaz de causar danos na memória de Wistar. A formação da memória implícita e explícita é prejudicada após a lesão em alguns núcleos serotoninérgicos.(AU)

Neuroendocrine signaling pathways and the nutritional control of puberty in heifers

Puberty is a complex physiological process in females that requires maturation of the reproductive neuroendocrine system and subsequent initiation of highfrequency, episodic release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Genetics and nutrition are two major factors controlling the timing of puberty in heifers. While nutrient restriction during the juvenile period delays puberty, accelerated rates of body weight gain during this period have been shown to facilitate pubertal development by programming hypothalamic centers that underlie the pubertal process. Among the different metabolic factors, leptin plays a critical role in conveying nutritional information to the neuroendocrine axis and controlling pubertal progression. Because GnRH neurons are devoid of the leptin receptor, leptin’s effects on GnRH neurons must be relayed via an afferent neuronal network. Two neuronal populations located in the arcuate nucleus (ARC) that express the orexigenic peptide neuropeptide Y (NPY), and the anorexigenic peptide alpha melanocyte-stimulating hormone (αMSH), are key components of afferent pathways that convey inhibitory (NPY) and excitatory (αMSH) inputs to GnRH neurons. In addition, ARC neurons expressing kisspeptin, a potent stimulator of GnRH release, are also involved in the nutritional regulation of puberty. Our studies have demonstrated that increased planes of nutrition during juvenile development result in morphological and functional changes in hypothalamic pathways comprising NPY, proopiomelanocortin (POMC), and kisspeptin neurons. Changes included differential expression of NPY, POMC, and Kiss1 in the ARC, and plasticity in the axonal projections to GnRH and kisspeptin neurons. Additionally, increased rates of body weight gain also promoted changes in the pattern of DNA methylation, a key epigenetic mechanism for regulation of gene expression. Finally, our most recent findings suggest that maternal nutrition during gestation can also induce structural and functional changes in hypothalamic neurocircuitries that are likely to persist long after pubertal maturation and influence reproductive performance throughout adulthood in cattle.

Neuroendocrine signaling pathways and the nutritional control of puberty in heifers

Puberty is a complex physiological process in females that requires maturation of the reproductive neuroendocrine system and subsequent initiation of highfrequency, episodic release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Genetics and nutrition are two major factors controlling the timing of puberty in heifers. While nutrient restriction during the juvenile period delays puberty, accelerated rates of body weight gain during this period have been shown to facilitate pubertal development by programming hypothalamic centers that underlie the pubertal process. Among the different metabolic factors, leptin plays a critical role in conveying nutritional information to the neuroendocrine axis and controlling pubertal progression. Because GnRH neurons are devoid of the leptin receptor, leptins effects on GnRH neurons must be relayed via an afferent neuronal network. Two neuronal populations located in the arcuate nucleus (ARC) that express the orexigenic peptide neuropeptide Y (NPY), and the anorexigenic peptide alpha melanocyte-stimulating hormone (αMSH), are key components of afferent pathways that convey inhibitory (NPY) and excitatory (αMSH) inputs to GnRH neurons. In addition, ARC neurons expressing kisspeptin, a potent stimulator of GnRH release, are also involved in the nutritional regulation of puberty. Our studies have demonstrated that increased planes of nutrition during juvenile development result in morphological and functional changes in hypothalamic pathways comprising NPY, proopiomelanocortin (POMC), and kisspeptin neurons. Changes included differential expression of NPY, POMC, and Kiss1 in the ARC, and plasticity in the axonal projections to GnRH and kisspeptin neurons. Additionally, increased rates of body weight gain also promoted changes in the pattern of DNA methylation, a key epigenetic mechanism for regulation of gene expression. Finally, our most recent findings suggest that maternal nutrition during gestation can also induce structural and functional changes in hypothalamic neurocircuitries that are likely to persist long after pubertal maturation and influence reproductive performance throughout adulthood in cattle.(AU)

In silico analysis of binding interaction of conantokins with NMDA receptors for potential therapeutic use in Alzheimer's disease

Background The N-methyl-D-aspartate (NMDA) receptors are glutamate receptors that play vital roles in central nervous system development and are involved in synaptic plasticity, which is an essential process for learning and memory. The subunit N-methyl D-aspartate receptor subtype 2B (NR2B) is the chief excitatory neurotransmitter receptor in the mammalian brain. Disturbances in the neurotransmission mediated by the NMDA receptor are caused by its overexposure to glutamate neurotransmitter and can be treated by its binding to an antagonist. Among several antagonists, conantokins from cone snails are reported to bind to NMDA receptors. Methods This study was designed to analyze the binding mode of conantokins with NMDA receptors in both humans and rats. To study interactions, dockings were performed using AutoDock 4.2 and their results were further analyzed using various computational tools. Results Detailed analyses revealed that these ligands can bind to active site residues of both receptors as reported in previous studies. Conclusions In light of the present results, we suggest that these conantokins can act as antagonists of those receptors and play an important role in understanding the importance of inhibition of NMDA receptors for treatment of Alzheimer's disease.(AU)

Assessment of serotonergic system in formation of memory and learning

Abstract We evaluated the involvement of the serotonergic system on memory formation and learning processes in healthy adults Wistar rats. Fifty-seven rats of 5 groups had one serotonergic nuclei damaged by an electric current. Electrolytic lesion was carried out using a continuous current of 2mA during two seconds by stereotactic surgery. Animals were submitted to learning and memory tests. Rats presented different responses in the memory tests depending on the serotonergic nucleus involved. Both explicit and implicit memory may be affected after lesion although some groups showed significant difference and others did not. A damage in the serotonergic nucleus was able to cause impairment in the memory of Wistar. The formation of implicit and explicit memory is impaired after injury in some serotonergic nuclei.

Resumo Avaliar a participação do sistema serotoninérgico em processos de formação de memória e aprendizagem em ratos Wistar adultos saudáveis. Cinquenta e sete ratos de 5 grupos tinham um núcleo serotoninérgico danificado por uma corrente elétrica. A lesão eletrolítica foi realizada utilizando uma corrente contínua de 2 mA durante dois segundos por cirurgia estereotáxica. Os animais foram submetidos a testes de aprendizagem e memória. Os ratos apresentaram respostas diferentes nos testes de memória, dependendo do núcleo serotoninérgica envolvido. A memória explícita e implícita pode ser afetada após a lesão, embora alguns grupos apresentaram diferença significativa e outros não. A lesão no núcleo serotoninérgico foi capaz de causar danos na memória de Wistar. A formação da memória implícita e explícita é prejudicada após a lesão em alguns núcleos serotoninérgicos.

Assessment of serotonergic system in formation of memory and learning

Abstract We evaluated the involvement of the serotonergic system on memory formation and learning processes in healthy adults Wistar rats. Fifty-seven rats of 5 groups had one serotonergic nuclei damaged by an electric current. Electrolytic lesion was carried out using a continuous current of 2mA during two seconds by stereotactic surgery. Animals were submitted to learning and memory tests. Rats presented different responses in the memory tests depending on the serotonergic nucleus involved. Both explicit and implicit memory may be affected after lesion although some groups showed significant difference and others did not. A damage in the serotonergic nucleus was able to cause impairment in the memory of Wistar. The formation of implicit and explicit memory is impaired after injury in some serotonergic nuclei.

Resumo Avaliar a participação do sistema serotoninérgico em processos de formação de memória e aprendizagem em ratos Wistar adultos saudáveis. Cinquenta e sete ratos de 5 grupos tinham um núcleo serotoninérgico danificado por uma corrente elétrica. A lesão eletrolítica foi realizada utilizando uma corrente contínua de 2 mA durante dois segundos por cirurgia estereotáxica. Os animais foram submetidos a testes de aprendizagem e memória. Os ratos apresentaram respostas diferentes nos testes de memória, dependendo do núcleo serotoninérgica envolvido. A memória explícita e implícita pode ser afetada após a lesão, embora alguns grupos apresentaram diferença significativa e outros não. A lesão no núcleo serotoninérgico foi capaz de causar danos na memória de Wistar. A formação da memória implícita e explícita é prejudicada após a lesão em alguns núcleos serotoninérgicos.

In silico analysis of binding interaction of conantokins with NMDA receptors for potential therapeutic use in Alzheimer's disease

Background The N-methyl-D-aspartate (NMDA) receptors are glutamate receptors that play vital roles in central nervous system development and are involved in synaptic plasticity, which is an essential process for learning and memory. The subunit N-methyl D-aspartate receptor subtype 2B (NR2B) is the chief excitatory neurotransmitter receptor in the mammalian brain. Disturbances in the neurotransmission mediated by the NMDA receptor are caused by its overexposure to glutamate neurotransmitter and can be treated by its binding to an antagonist. Among several antagonists, conantokins from cone snails are reported to bind to NMDA receptors. Methods This study was designed to analyze the binding mode of conantokins with NMDA receptors in both humans and rats. To study interactions, dockings were performed using AutoDock 4.2 and their results were further analyzed using various computational tools. Results Detailed analyses revealed that these ligands can bind to active site residues of both receptors as reported in previous studies. Conclusions In light of the present results, we suggest that these conantokins can act as antagonists of those receptors and play an important role in understanding the importance of inhibition of NMDA receptors for treatment of Alzheimer's disease.(AU)

Investigação dos efeitos do ácido 2, 4 diclorofenoxiacético sobre diferentes populações de neurônios mioentéricos do duodeno de ratos / Investigation of 2, 4 dichlorophenoxyacetic acid effects in different population of rat duodenum myenteric neurons / Investigación de los efectos del ácido 2, 4 diclorofenoxiacético sobre diferentes poblaciones de neuronas mioentéricas del duodeno de ratones

O herbicida mais usado, tanto em pequenas como em grandes propriedades, por isso mais amplamente estudado é o 2,4-D. Os estudos de toxicidade têm se concentrado sobre as alterações do sistema nervoso central, e por isto pouco se conhece sobre seus efeitos no sistema nervoso entérico. Com o objetivo de avaliar os efeitos do 2,4-D sobre os neurônios mioentéricos do duodeno de ratos foi fornecido durante 60 dias doses de 2,4-D na concentração de 5mg/kg de peso de corpóreo para ratosWistarde dois grupos experimentais (n=5). Os animais dos grupos controle permaneceram o mesmo período sem receber 2,4-D. Ao final do período experimental os animais foram mortos, os duodenos foram coletados e processados por meio das técnicas histoquímicas de NADH-diaforase e NADPH-diaforase. Os neurônios foram quantificados e os resultados foram analisados estatisticamente. A densidade dos neurônios NADHd diferiu estatisticamente (P?0,05) entre os grupos experimental e controle, sendo maior no grupo controle. Já os neurônios NADPHd foram encontrados em maior quantidade no grupo experimental. Estes resultados sugerem que o 2,4-D possui ação neurotóxica sobre os neurônios do plexo mioentérico, interferindo na densidade neuronal mioentérica, quando se compara diferentes populações destes neurônios.(AU)

The 2,4-D herbicide is the most widely used, both in small and in large properties. Therefore, it is also the one that is most broadly studied. Toxicity studies have been focused on changes in the central nervous system, and for this reason, little is known about its effect in the enteric nervous system. With the objective of measuring the effects of 2,4-D on the myenteric neurons in the duodenum of rats, doses of 2,4-D were supplied for 60 days at a concentration of 5mg/kg of body weight to Wistar rats divided into two different experimental groups (n=5). The animals in the control groups remained without 2,4-D doses for the same period. At the end of the experimental period, the animals were euthanized and their duodenum were collected and processed through NADH-diaphorase and NADPH-diaphorase histochemical techniques. The neurons were quantified and the results were statistically analyzed. The density of NADHd neurons differed statistically (P< 0,05) between the experimental and control groups, being higher in the control group. However, NADPHd neurons were found in a greater quantity in the experimental group. These results suggest that the 2,4-D has a neurotoxic action in the neurons from the myenteric plexus, interfering in the myenteric neuronal density, when different population of these neurons are compared.(AU)

El herbicida más utilizado, tanto en pequeñas como en grandes propiedades es el 2,4-D, por eso lo más estudiado. Los estudios de toxicidad se han centrado sobre las alteraciones del sistema nervioso central, y por lo tanto, poco se sabe sobre sus efectos en el sistema nervioso entérico. Con el objetivo de evaluar los efectos del 2,4-D sobre las neuronas mioentéricas del duodeno de ratas se ha administrado durante 60 días dosis de 2,4-D en la concentración de 5mg/kg de peso corporal para ratones Wistarde, dos grupos experimentales (n = 5). Los animales de los grupos control permanecieron el mismo período sin recibir el 2,4-D. Al final del periodo experimental los animales fueron sacrificados, los duodenos fueron recogidos y procesados a través de las técnicas de histoquímicas de NADH-diaforasa y NADPH-diaforasa. Las neuronas fueron cuantificadas y los resultados analizados estadísticamente. La densidad de las neuronas NADHd difirió estadísticamente (P?0,05) entre los grupos experimental y control, siendo mayor en el grupo control. Ya las neuronas NADPHd se encontraron en mayor cantidad en el grupo experimental. Estos resultados sugieren que el 2,4-D tiene una acción neurotóxica sobre las neuronas del plexo mioentérico, lo que interfiere en la densidad neuronal mioentérica al comparar diferentes poblaciones de estas neuronas. (AU)

Diferenciação neuronal de células-tronco de dente decíduo esfoliado

As células-tronco (CT) são células que apresentam propriedades de auto-renovação, capazes de gerar diferentes tipos celulares e reconstituir diversos tipos de tecidos, por isso têm sido vistas como uma alternativa terapêutica para o tratamento de muitas doenças cujo tratamento convencional não é eficiente. Além disso, por sua plasticidade, as CT podem ser usadas para produzir modelos in vitro para o estudo de doenças, o que tem sido particularmente interessante para doenças que acometem o sistema nervoso. As células-tronco humanas de dente decíduo esfoliado (Stem cell from Human Esfoliated Deciduous teeth, SHED) são descritas em alguns trabalhos como capazes de se diferenciarem em células neuronais através da transdiferenciação direta, um processo simples que possibilita a diferenciação de um tipo celular em outro por meio da utilização de agentes químicos. No entanto, a diferenciação de SHED em neurônios é contestada como sendo um artefato de cultura devido ação citotóxica destes agentes. Com base nesta premissa, o objetivo deste trabalho foi realizar protocolos para a produção de neurônios a partir das SHED utilizando modificações de métodos descritos na literatura e utilizados na diferenciação neuronal. Durante um dos protocolos utilizados, foi possível verificar a morfologia de células semelhantes à neurônio, porém após alguns dias de manutenção, as células voltavam ao formato fusiforme original. Com este trabalho podemos afirmar que, de acordo com os resultados obtidos, as SHED não geram neurônios funcionais.

Stem cells (SC) are cells that present self-renewal properties, capable of generating cells types and reconstitute several tissue types. For this reason, they have been seen as a therapeutic alternative to the treatment of many diseases which conventional treatment is not efficient. Besides, because of its plasticity, SC may be used to produce in vitro models in order to study diseases, what is interesting to diseases that affect the nervous system. Human SC from SHED (Stem cell from Human Exfoliated Deciduous teeth, SHED) are described in some papers as being capable of self-differentiation in neuronal cells through the direct transdifferentiation, a simple process that makes possible the differentiation of a cell type in another through the use of chemical agents. Nevertheless, SHED differentiation is refuted as being a artifact of culture due to cytotoxic action of these agents. Based on this premise, the aim of this study was to carry out protocols in order to produce neurons from SHED, using modifications and methods of neuronal differentiation described in the literature and used in the neuronal differentiation. During one of the protocols used, it was possible to verify the morphology of the cells as neuron-like, however, after some days of maintenance, they turn back to their original fusiform format. In this study, we can state, according to the obtained results, that SHED do not generate functional neurons.

Transplante alogênico de células-tronco mesenquimais induz alteração do perfil de citocinas pró e antiflamatórias e de fatores neurotróficos no tratamento da lesão espinal

O objetivo deste estudo foi comparar dois protocolos de tratamento da lesão espinal aguda com células-tronco mesenquimais criopreservadas, extraídas do tecido adiposo (CTM-AD) de ratos Lewis eGFP. Avaliou-se a expressão de marcadores de superfície, capacidade de diferenciação e viabilidade celular pré e pós criopreservação de CTM-ADsubmetidas à três meios de criopreservação com concentrações distintas de soro fetal bovino (SFB). Os resultados demonstraram que as CTM-AD não perdem sua multipotência, não modificam a expressão fenotípica e apresentam alta viabilidade celular por até 90 dias de criopreservação. Avaliou-se também os efeitos imunomodulatórios e neuroprotetores do tratamento único (grupo GI) e duplo (grupo GII) com CTM-AD alogênicas criopreservadas por via intravenosa após lesão espinal Os grupos tratados (GI e GII) foram avaliados conjuntamente com o grupo sham (GS) e controle negativo (GC) atravéz da escala de função motora (BBB), expressão dos transcriptos gênicos de interleucina-10 (IL-10), interleucina-1 beta (IL-1), fator de necrose tumoral alfa (TNF-), fator de transformação do crescimento (TGF-), fator neurotrófico derivado do cérebro (BDNF), fator neutrófico derivado da glia (GDNF) e fator de crescimento endotelial vascular (VEGF). Adicionalmente realizou-se quantificação por imunohistoquímica do infiltrado inflamatório (anti-CD68), integridade neuronal (anti-NeuN), e ativação de astrócitos (anti-GFAP). Quando comparado ao grupo GC, os grupos tratados com CTM apresentaram maiores escores nas avaliações funcionais a partir de 72h após lesão, sendo a média dos maiores escores alcançada pelo grupo GII; menor expressão de CD68 e GFAP juntamente com a redução da degeneração da substância branca e maior expressão de NeuN. O tratamento com as células também resultou em aumento da expressão de IL-10, GDNF, VEGF e redução da expressão de TNF- e TGF-. Adicionalmente o grupo GII apresentou redução da expressão de IL-1 e aumento da expressão de BDNF. Conclui-se que o tratamento alogênico com duas aplicações de CTM-AD criopreservadas promove melhor recuperação da atividade motora, reduz o infiltrado inflamatório, ativa células da micróglia/macrógafos com fenótipo antinflamatório, aumenta a quantidade de neurônios íntegros, reduz a degeneração da substância branca e a ativação de astrócitos na medula espinal e aumenta a secreção do fator neurotrófico BDNF.

This thesis aimed to compare two treatment protocols with cryopreserved allogenic adipose-derived mesenchymal stem cells (AD-MSC) after spinal cord injury. Experiment 1 evaluated pre-freeze and pos-freeze populations of AD-MSCs response to freezing at 30, 60 and 90 days following cryopreservation. Plasticity, cell surface phenotype and cell viability were evaluated at different times after thawing technique. Results showed that MSC do not lose their multipotency, do not alter phenotypic profile and have a high cell viability for up to 90 days of cryopreservation. Experiment 2 evaluated the immunomodulatory and neuroprotective effects of cryopreserved allogenic adipose-derived MSCs after spinal cord injury (SCI). Treatment effects were comparatively evaluated by quantitation of gene expression of interleukin-10 (IL-10), interleukin-1 beta (IL-1), tumor necrosis factor (TNF-), transforming growth factor (TGF -), brain-derived neurotrophic factor (BDNF), glial derived neurotrophic factor (GDNF) and vascular endothelial growth factor (VEGF). Immunohistochemical analyzes were used to quantify inflammatory infiltrate (anti-CD68), neural integrity (anti-NeuN), and astrocytes activation (anti-GFAP). Frozen adipose-derived MSCs were transplanted after three hours (GI) and three hours and seven days after SCI (GII). The results were compared with animals without SCI (GS) and SCI without treatment (GC). MSCs treated groups had higher scores in functional assessments from 72h after injury, being the average of the highest scores achieved by the GII; lower expression of CD68 and GFAP along with reducing of degeneration of the white matter and increased expression of NeuN. The treatment with the cells also resulted in increased IL-10 expression, GDNF, VEGF and reduced of TNF- and TGF- expression. Additionally the GII decreased IL-1 expression and increased BDNF expression. The results suggest that early intravenous injection of AD-MSCs after acute SCI promotes better recovery of function, prevent futher damage through enhancement of anti-inflammatory mechanisms, reduces the inflammatory infiltrate, active anti-inflammatory phenotype of microglia, increase neuron viability, reduces the degeneration of the white matter and astrocyte activation in SCI. In addition, treatment with double applications of AD-MSCs was superior to the single administration of these cells, resulting in improved motor response and secretion of BDNF.

Modelagem neuronal de pacientes com distrofia muscular de Duchenne utilizando células pluripotentes induzidas

A Distrofia Muscular de Duchenne (DMD) é uma patologia neuromuscular causada pela mutação ou deleção do gene da distrofina, localizado no cromossomo X, levando a degeneração muscular ao longo da vida do paciente. A doença também tem sido associada a déficit cognitivo e falta de habilidade comportamental. Pesquisas com células neurais de pacientes com DMD poderiam ajudar a elucidar os sintomas neurológicos associados. Neste trabalho, através de células-tronco pluripotentes induzidas (iPSC) derivadas da polpa de dente decíduo esfoliado (SHED) de pacientes com DMD modelamos a DMD produzindo células neurais vivas in vitro. A expressão da distrofina foi verificada durante e após a diferenciação neuronal e nos ensaios de imunofluorescência, mostrando que essa proteína está presente em células do SNC. Na análise gênica através do qPCR, a Dp71 e a Dp140, isoformas da distrofina, apresentavam uma expressão menor do que os controles. Além disso, as análises das sinapses baseada na colocalização de marcadores pré e pós-sinápticos (Sinapsina1 e Homer 1) revelaram que os neurônios dos pacientes com DMD tinham menor quantidade de sinapses que os controles, reforçando o papel da distrofina no SNC. Logo, a expressão de genes relacionados a plasticidade sináptica revelou 10 genes alterados nos neurônios dos pacientes DMD, sugerindo que a mutação no gene da distrofina possivelmente altera a plasticidade sináptica e pode estar envolvida na habilidade cognitiva destes pacientes. Desta forma, com base nos nossos achados, a modelagem neuronal de DMD é factível e pode auxiliar a elucidar os mecanismos da fisiopatologia da doença.

The Duchenne muscular dystrophy (DMD) is a neuromuscular disorder caused by a mutation or deletion of the dystrophin gene located on the X chromosome, leading to muscle degeneration throughout the patient's life. The disease has also been associated with cognitive impairment and lack of behavioral skill. Research on neural cells from patients with DMD could help to elucidate the neurological symptoms associated. In this work, through induced pluripotent stem cells (iPSC) derived from dental pulp exfoliated (SHED) of patients with DMD model the DMD producing living neural cells in vitro. The dystrophin expression was observed during and after neuronal differentiation and immunofluorescence assays, showing that this protein is present in CNS cells. In gene analysis by qPCR, the Dp71 and Dp140, isoforms of dystrophin, had a lower expression than controls. Furthermore, based on analysis of synapses colocalization pre and postsynaptic markers (Synapsin1 and Homer 1) showed that neurons of DMD patients had lower number of synapses controls, supporting a role for dystrophin in the CNS. Finally, the expression of synaptic plasticity related genes wasfound in 10 genes altered in neurons of DMD patients, suggesting that the mutation of the dystrophin gene possibly alters synaptic plasticity and may be involved in cognitive ability of these patients. Finally, based on our findings, neuronal modeling DMD is feasible and may help elucidate the mechanisms of pathophysiology of the disease.

Fenótipo e multipotencialidade de células progenitoras de membrana amniótica de Coelho (Oryctolagus cuniculus)

As células tronco possuem a capacidade de auto renovação ilimitada e de se manterem indiferenciadas durante um período prolongado de tempo, até se diferenciarem em uma linhagem celular específica. Devido as dificuldades encontradas na utilização de células embrionárias por questões éticas, de segurança e histocompatibilidade e a limitada plasticidade das células tronco adultas, as células tronco fetais, derivadas de tecidos extraembrionários, aparecem no cenário terapêutico como uma alternativa promissora. Uma vez que apresentam alta capacidade de proliferação e expansão in vitro, além de sua característica imunogênica, por se encontrarem na interface materno fetal. Por conta destas características, a membrana amniótica surgiu como uma nova e importante fonte de células tronco em diferentes espécies. Neste trabalho, foram utilizados 8 fetos de coelhos para a coleta da membrana amniótica. A membrana foi isolada pela técnica de explante, as amostras foram cultivadas em meio DMEM-HIGH, e posteriormente criopreservadas nas passagens P4 e P8 para realizar os experimentos. Em cultivo, essas células apresentaram aderência a placa, alta capacidade de proliferação e morfologia semelhante à fibroblastos. Na caracterização imunofenotípica, houve expressão de marcadores de citoesqueleto, de células mesenquimais, proliferação, pluripotência e para precursores de células hematopoiéticas, embora não tenha ocorrido a expressão de marcadores de células hematopoiéticas (CD-45) e de células precursoras neuronais. Quando induzidas a diferenciação in vitro, as células amnióticas tiveram capacidade de se diferenciarem nas linhagens osteogênica, adipogênica e condrogênica. Além disso, quando injetadas em camundongos nude, não foi verificada a formação de tumor. Nossos resultados demostram que células de membrana amniótica de coelho podem ser consideradas células tronco mesenquimais com possibilidade de serem utilizadas no futuro na terapia celular.

Stem cells are capable of unlimited self renewal and to remain undifferentiated for a prolonged period of time up to differentiate into a specific cell lineage. Due to the difficulties in the use of embryonic cells due ethical reasons, security and histocompatibility, and in the other hands, the limited plasticity of adult stem cells, fetal stem cells, derived from extraembryonic tissues, appear in the therapeutic setting as a promising alternative. They have high capacity of proliferation and in vitro expansion, as well as immunogenic properties, since they are at the maternal-fetal interface. Due to these characteristics, the amniotic membrane has emerged as an important new source of stem cells in different species. In this work, we used 8 fetuses of rabbits to collect amniotic membrane. The membrane was isolated by the explant technique. Samples were cultured in DMEM-HIGH, and cryopreserved in the passages P4 and P8 in order to perform the experiments. In culture, these cells exhibited adhesion to the dishes, high proliferative capacity and fibroblast-like morphology. In immunophenotypic characterization, there was expression of markers related to cell cytoskeleton, mesenchymal stem cells, proliferation, pluripotency, and hematopoietic precursor cells. And there was no expression of hematopoietic cell markers (CD-45) and neuronal precursor cells. When induced to in vitro differentiation, the amniotic cells were able to differentiate in osteogenic, adipogenic and chondrogenic lineages. Furthermore, when injected into nude mice, tumor formation has not been verified. Our results demonstrate that rabbit amniotic membrane cells can be considered mesenchymal stem cells with possibility to be used in the future in cell therapy.

S100ß and fibroblast growth factor-2 are present in cultured Schwann cells and may exert paracrine actions on the peripheral nerve injury / S100ß e fator de crescimento de fibroblasto-2 estão presentes nas células de Schwann cultivadas e exercem ações parácrinas na lesão do nervo

PURPOSE: The neurotrophic factor fibroblast growth factor-2 (FGF-2, bFGF) and Ca++ binding protein S100ß are expressed by the Schwann cells of the peripheral nerves and by the satellite cells of the dorsal root ganglia (DRG). Recent studies have pointed out the importance of the molecules in the paracrine mechanisms related to neuronal maintenance and plasticity of lesioned motor and sensory peripheral neurons. Moreover, cultured Schwann cells have been employed experimentally in the treatment of central nervous system lesions, in special the spinal cord injury, a procedure that triggers an enhanced sensorymotor function. Those cells have been proposed to repair long gap nerve injury. METHODS: Here we used double labeling immunohistochemistry and Western blot to better characterize in vitro and in vivo the presence of the proteins in the Schwann cells and in the satellite cells of the DRG as well as their regulation in those cells after a crush of the rat sciatic nerve. RESULTS: FGF-2 and S100ß are present in the Schwann cells of the sciatic nerve and in the satellite cells of the DRG. S100ß positive satellite cells showed increased size of the axotomized DRG and possessed elevated amount of FGF-2 immunoreactivity. Reactive satellite cells with increased FGF-2 labeling formed a ring-like structure surrounding DRG neuronal cell bodies.Reactive S100ß positive Schwann cells of proximal stump of axotomized sciatic nerve also expressed higher amounts of FGF-2. CONCLUSION: Reactive peripheral glial cells synthesizing FGF-2 and S100ß may be important in wound repair and restorative events in the lesioned peripheral nerves.(AU)

OBJETIVO: O fator neurotrófico fator de crescimento de fibroblastos-2 (FGF-2, bFGF) e a proteína ligante de Ca++ S100ß são expressos pelas células de Schwann dos nervos e por células satélites do gânglio da raiz dorsal (GRD). Estudos recentes indicam a importância das moléculas nos mecanismos parácrinos relacionados à manutenção neuronal e à plasticidade de neurônios periféricos motores e sensoriais. Além disso, células de Schwann cultivadas têm sido empregadas experimentalmente no tratamento de lesões no sistema nervo central, especialmente na lesão da medula espinal, a qual mostrou uma melhora da função sensoriomotora. Estas células são ainda propostas no reparo do nervo lesado com perda de tecido. MÉTODOS: Usamos a dupla marcação imunohistoquímica e o Western blot para caracterizar melhor in vitro e in vivo a presença das proteínas nas células de Schwann e nas células satélites do GRD assim como sua regulação nessas células após a compressão do nervo ciático de ratos. RESULTADOS: FGF-2 e S100ß estão presentes nas células de Schwann do nervo ciático e nas células satélites do GRD. Células satélites do GRD axotomizado positivas para S100ß possuíam quantidade aumentada de imurreatividade da FGF-2. Células satélites reativas apresentando maior quantidade de FGF-2 formaram um anel ao redor dos corpos neuronais do GRD. Células de Schwann do coto proximal à axotomia do nervo ciático e positivas para S100ß também expressaram quantidades aumentadas de FGF-2. CONCLUSÃO: As células gliais periféricas ao sintetizar FGF-2 e S100ß podem ser importantes no reparo de cicatrização e em eventos restaurativos nas lesões do nervo.(AU)

Differential astroglial responses in the spinal cord of rats submitted to a sciatic nerve double crush treated with local injection of cultured Schwann cell suspension or lesioned spinal cord extract: implications on cell therapy for nerve repair / Respostas astrocitárias na medula espinal do rato submetido ao esmagamento duplo do nervo ciático e tratado com injeção local de suspensão de células de Schwann cultivadas ou de extrato de medula espinal lesada. Implicações na terapia celular para o reparo do nervo

PURPOSE: Reactive astrocytes are implicated in several mechanisms after central or peripheral nervous system lesion, including neuroprotection, neuronal sprouting, neurotransmission and neuropathic pain. Schwann cells (SC), a peripheral glia, also react after nerve lesion favoring wound/repair, fiber outgrowth and neuronal regeneration. We investigated herein whether cell therapy for repair of lesioned sciatic nerve may change the pattern of astroglial activation in the spinal cord ventral or dorsal horn of the rat. METHODS: Injections of a cultured SC suspension or a lesioned spinal cord homogenized extract were made in a reservoir promoted by a contiguous double crush of the rat sciatic nerve. Local injection of phosphate buffered saline (PBS) served as control. One week later, rats were euthanized and spinal cord astrocytes were labeled by immunohistochemistry and quantified by means of quantitative image analysis. RESULTS: In the ipsilateral ventral horn, slight astroglial activations were seen after PBS or SC injections, however, a substantial activation was achieved after cord extract injection in the sciatic nerve reservoir. Moreover, SC suspension and cord extract injections were able to promote astroglial reaction in the spinal cord dorsal horn bilaterally. Conclusion: Spinal cord astrocytes react according to repair processes of axotomized nerve, which may influence the functional outcome. The event should be considered during the neurosurgery strategies(AU)

OBJETIVO: Astrócitos reativos participam de vários mecanismos após lesões do sistema nervoso central e periférico, os quais incluem neuroproteção, brotamento neuronal, neurotransmissão e dor neuropática. As células de Schwann (CS), um tipo de glia periférica, também reagem com a lesão do nervo, podendo interferir com o reparo e cicatrização, crescimento de fibras e regeneração neuronais. Investigamos aqui a possibilidade da terapia celular para o reparo do nervo ciático poder alterar o padrão da ativação astrocitária nos cornos anterior e posterior da medula espinal do rato. MÉTODOS: Suspensão de CS cultivadas ou extrato homogeneizado de medula espinal lesada de rato foram inoculados num reservatório feito a partir de dois esmagamentos aplicados no nervo ciático do rato distantes 0,5mm entre si. Injeção local de salina tamponada serviu como controle. Os ratos foram mortos uma semana após e os astrócitos da medula espinal marcados por método imunohistoquímico e quantificados por análise de imagem. RESULTADOS: No corno anterior da medula, ipsilateral à lesão, ativação astrocitária leve foi vista após as injeções de tampão ou CS, entretanto, ativação celular intensa foi observada nesta região com a inoculação neural do extrato homogeneizado de tecido medular lesado. Adicionalmente, as inoculações de CS e de extrato homogeneizado de tecido medular promoveram forte reação astrocitária no corno dorsal da medula espinal, bilateralmente. CONCLUSÕES: Os astrócitos da medula espinal reagem em função do processo de reparo do nervo lesado, o que pode influenciar o resultado funcional esperado, algo que deve ser considerado durante o planejamento da estratégia neurocirúrgica(AU)

Análise morfométrica e quantitativa dos neurônios do plexo mientérico do ceco de ratos submetidos a intensa carência de proteína / Análisis morfométrica y cuantitativa de las neuronas del plexo mientérico del ceco de ratas sometidos a una intensa carencia de proteína / Quantitative and morphometric analysis of myenteric neuron from the cecum of rats submitted to intensive protein deficiency

Avaliaram-se os efeitos crônicos de uma dieta severamente hipoprotéica, sobre aspectos quantitativos e morfométricos de neurônios mientéricos, NADPH-diaforase positivos do ceco de ratos jovens. Oito ratos foram divididos em dois grupos, sendo que para um dos grupos foi oferecida ração com teor protéico de 26% (controle) e, para o outro, ração com o teor protéico de 4%, mantendo-se o balanço vitamínico e mineral durante 12 semanas. Após eutanásia, o ceco de cada animal foi coletado e dissecado para confecção de preparados de membrana, os quais foram submetidos à técnica da NADPH-diaforase. Para contagem e mensuração destes neurônios, o ceco foi dividido em quatro regiões: apical mesentérica; apical antimesentérica; basal antimesentérica; próxima à ampola cecal. Não se observou alteração significativa para o peso dos animais, área do ceco e densidade populacional dos neurônios mientéricos no final do experimento. Por outro lado, em algumas regiões do ceco, os neurônios tiveram redução da área nuclear, com conseqüente redução da área do pericário(AU)

The chronicle effects of a severe hypoproteic diet on quantitative and morphometric aspects of NADPHdiaphorase-positive myenteric neurons from the cecum of young rats were assessed. Eight rats were divided into two groups. One group (control) was fed with 26%-protein chow and the other with 4%-protein chow during 12 weeks. The vitamin and mineral balance was kept. After euthanasia, the cecum of each animal was collected and dissected for the whole-mount preparation, which were submitted to NAPDH-diaphorase. The cecum was divided into four regions for counting and measurement of neurons: apical mesenteric, antimesenteric apical, basal antimesenteric, and next to the cecal ampulla. Significant alterations were not noted with respect to the weight of the animals, cecum area, and population density of myenteric neurons at the end of the experiment. On the other hand, in some regions of the cecum, the neurons presented a reduction of the nuclear area with resulting reduction of the soma area(AU)

Se evaluaron los efectos crónicos de una dieta severamente hipoprotéica, sobre aspectos cuantitativos y morfométricos de neuronas mientéricos, NADPH-diaforase positivos del ceco de ratas jóvenes. Ocho ratas fueron divididas en dos grupos, siendo que para uno de los grupos fue ofrecida ración con tenor proteico de 26% (control) y, para el otro, ración con el tenor proteico de 4%, manteniéndose el balance vitamínico y mineral durante 12 semanas. Tras eutanasia, El ceco de cada animal fue recolectado y disecado para confección de preparados de membrana, los cuales fueron sometidos a la técnica de la NADPH-diaforase. Para recuento y mensuración de estas neuronas, el ceco fue dividido en cuatro regiones: apical mesentérica, apical antimesentérica, basal antimesentérica y próxima a la ampolla cecal. No se observó alteración significativa en el peso de los animales, área del ceco y densidad poblacional de las neuronas mientéricas al final Del experimento. Por otro lado, en algunas regiones del ceco las neuronas tuvieron reducción del área nuclear, con consecuente reducción del área del pericario(AU)

Efeitos da alimentação com diferentes níveis calóricos nos neurônios mioentéricos do cólon de ratos Wistar durante o processo de envelhecimento / Effects of food with different caloric levels in myenteric neurons of the colon of rats during the aging process

Os últimos anos se caracterizaram pelo aumento significativo da população idosa mundial. Por esta razão, a preocupação com o idoso está se tornando uma constante em nossa sociedade, uma vez que o envelhecimento resulta em comprometimento das funções fisiológicas, acompanhado ou não de alterações estruturais. No trato gastrointestinal (TGI), o processo de envelhecimento pode provocar alterações morfofuncionais significativas. A regulação da motilidade do TGI é controlada principalmente pelos neurônios mioentéricos do sistema nervoso entérico. A diminuição na densidade destes neurônios no cólon pode levar à redução na frequência e na amplitude da contração colônica manifestada como constipação. As ações que visam diminuir os efeitos do envelhecimento no TGI incluem aquelas relacionadas à dieta alimentar, entre as quais se destaca a restrição calórica. A restrição calórica, além de apresentar efeito protetor nos neurônios mioentéricos durante o envelhecimento, também é responsável pela diminuição da morte neuronal por apoptose, processo este acentuado com o envelhecimento. Assim sendo, este trabalho teve por objetivo avaliar os efeitos de diferentes níveis de restrição calórica sobre a plasticidade dos neurônios mioentéricos NADPH e acetilcolinesterase positivos do cólon de ratos Wistar durante o processo de envelhecimento por meio das análises ultraestrutural (microscopia eletrônica de transmissão) e morfoquantitativa. Para tanto foram utilizados 40 ratos machos (Rattus norvegicus), da linhagem Wistar, distribuídos em quatro grupos (n= 10/grupo): CI- animais de seis meses; SR- animais de 18 meses alimentados com dieta normal; RCI- animais de 18 meses alimentados com dieta com 12% de restrição calórica; RCII- animais de 18 meses submetidos à restrição calórica de 30%. Aos seis meses de idade, os animais foram transferidos para o biotério setorial, onde permaneceram até aos 18 meses sob condições ambientais controladas de temperatura e de iluminação e água ad libitum. Foi possível observar que a RC em nível de 30% minimizou de forma eficaz os efeitos deletérios do envelhecimento nos neurônios mioentéricos, podendo ser adotada como alternativa contra os distúrbios gastrointestinais comuns em indivíduos idosos

The last years were characterized by a significant increase in the elderly population. For this reason, concern for the elderly is becoming a constant in our society, since the aging results in impairment of bodily function, or not accompanied by structural changes. In the gastrointestinal tract (GI), the aging process can cause significant morphological changes. The regulation of motility of the gut is controlled mainly by myenteric neurons of the enteric nervous system. The decrease in the density of neurons in the colon can lead to a reduction in the frequency and amplitude of contraction expressed as colonic constipation. The actions aimed at reducing the effects of aging on the GI system include those related to diet, among which stands out caloric restriction. Caloric restriction, and have a protective effect on the myenteric neurons during aging, is also responsible for the decrease of neuronal death by apoptosis, a process accentuated with aging. Thus, this study was to evaluate the effects of different levels of calorie restriction on the plasticity of myenteric neurons NADPH and acetylcholinesterase positive of the colon of rats during the aging process by means of ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Therefore, we used 40 male Wistar rats (Rattus norvegicus), divided into four groups (n = 10): CI- animals six months; SR- animals 18 month fed a normal diet; RCI - animals 18 months fed a diet with 12% caloric restriction; RCII- animals 18 months fed a diet with 30% caloric restriction. At six months, the animals were transferred to the vivarium sector, where they remained up to 18 months under controlled conditions of temperature and light and water ad libitum. It was observed that the RC level of 30% effectively minimized the deleterious effects of aging on myenteric neurons, which may be adopted as an alternative against the common gastrointestinal disorders in the elderly

EXPERIMETAL MICRONEUROSURGERY OF THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM IN THE STUDY OF THE NEURONAL AND GLIAL TROPHISM AND PLASTICITY

Trauma and neurodegenerative diseases commit the nervous system. After an axotomy or nerve injury in the peripheral nervous system the regeneration of the nerve fibers and reinervation of the target are seen. In central nervous system these events are restrictive, however their occurrence are related to the state of glial reaction and the synthesis of neurotrophic factors. Basic fibroblast growth factor (bFGF) has been considered an important trophic factor for neurons and astrocytes of many central nervous system regions. In this study rats were submitted to one of following neurosurgery procedures: callosotomy, pyramidectomy or complete transection of hypoglossal nerve (XII). Sham operations were made in control animals. Seven days later animals were sacrificed and their brains processed for immunohistochemistry. Coronal sections were taken from the central nervous system and incubated with antisera against the glial fibrillary acidic protein (GFAP) or neurofilament (NF), markers for astrocyte and neuronal cell body and fibers, respectively, as well as with the antiserum against the bFGF. The degree of the labelling was quantified with computer assisted stereological methods. The analysis of the NF immunoreactivity revealed a disappearance of fibers in the white matter distal to the pyramidectomy and callosotomy, however no disappearance of NF immunoreactive neurons was found in the XII nucleus following axotomy. These changes was accompanied by a massive astrocytic reaction. The reactive astrocytes synthesized increased amounts of bFGF. These findings suggest that glial reaction synthesizing neurotrophic factors may influence the wound and repair after mechanical lesions of central nervous and subsequent neuronal trophism and plasticity which may be relevant to the regenerative process of the nervous tissue