RESUMO

One of the plastic base material, widely used in the plastics industry in various countries, is a ester phthalate. These compounds will be oxidizedin the body to 2-methoxyethanol (2-ME). Effect of 2-ME on human health and the environment depends on the number, duration and frequency of exposure. 2-ME and its metabolites in the body can damage cells and tissues. The body can be exposed by 2-ME through the air, water and soil. Western blot results showed that the protein Vimentin was detectable in the control group at GD-11 to 17, meanwhile GFAP protein was detachable in the control group atGD- 12 to GD-18. After administration 2-ME, the expression of Vimentinprotein were changed, and started at GD- 12 up to GD-18. whereas the expression of GFAP protein began at GD-11 up to GD-17. The Changes on timetable protein expression of Vimentin and GFAP affect corticogenesis disorder. The disorder caused by the existence of these proteins as a result of 2-Methoxyethanol. Disorder of corticogenesis process were sub-plate and cortical plate of the cerebral cortex of fetus brains of mice at GD-18. Generally, it can be concluded that changes inprotein expression of Vimentin and GFAP causedby 2-ME. The Vimentin more important during the period of fetal brain development. GFAP and Vimentin is a protein involved in response to damage caused by a teratogenic agent, so that cells in the cerebral cortex, has dedifferentiation.

Uno de los materiales a base de plástico, ampliamente utilizado en la industria en varios países, es un éster de ftalato. Estos compuestos se oxidan en el cuerpo a 2-metoxietanol (2-ME). El efecto del 2-ME en la salud humana y el medio ambiente depende de la cantidad, duración y frecuencia de exposición. El 2-ME y sus metabolitos en el cuerpo puede dañar las células y tejidos. El cuerpo puede ser expuesto al 2-ME a través del aire, agua y suelo. Los resultados de Western blot mostraron que la proteína vimentina fue detectable en el grupo de control en GD-11 a 17, por su parte proteína GFAP fue detectable en el grupo de control en GD-12 a GD-18. Después de la administración de 2-ME, la expresión de la proteína vimentina cambió, y comenzó a detectarse en GD-12 hasta GD-18, mientras que la expresión de la proteína GFAP se inició en GD-11 hasta GD-17. Los cambios en el momento de expresión de las proteínas vimentina y GFAP afectan produciendo trastornos de la corticogénesis. El trastorno causado por la existencia de estas proteínas como resultado de 2-metoxietanol a nivel del proceso corticogénesis fue en la subplaca y la placa cortical de la corteza cerebral del cerebro de fetos de ratones en GD-18. En general, se puede concluir que existen cambios en la expresión de las proteínas vimentina y GFAP causados por el 2-ME. La vimentina es muy importante durante el período de desarrollo del cerebro fetal. GFAP y vimentina son proteínas implicadas en la respuesta a los daños causados por un agente teratogénico, de modo que las células en la corteza cerebral presentan desdiferenciación.

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RESUMO

Axons and glial cells are the main components of white matter. The corpus callosum (CC) is the largest white matter tract in mammals; in rodents, 99% of the cells correspond to glia after postnatal day 5 (P5). The area of the CC varies through life and regional differences related to the number of axons have been previously described. Whether glial cell density varies accordingly is unknown; thus the aim of this study was to estimate glial cell density for the genu, body and splenium -the three main regions of CC-, of P6 and P30 rats. Here we report that the density of CC glial cells reduced by ~10% from P6 to P30. Even so, the density of astrocytes showed a slight increase (+6%), probably due to differentiation of glioblasts. Interestingly, glial cell density decreased for the genu (-21%) and the body (-13%), while for the splenium a minor increase (+5%) was observed. The astrocyte/glia ratio increased (from P6 to P30) for the genu (+27%), body (+17%) and splenium (+4%). Together, our results showed regional differences in glial cell density of the CC. Whether this pattern is modified in some neuropathologies remains to be explored.

Assuntos

RESUMO

Axons and glial cells are the main components of white matter. The corpus callosum (CC) is the largest white matter tract in mammals; in rodents, 99% of the cells correspond to glia after postnatal day 5 (P5). The area of the CC varies through life and regional differences related to the number of axons have been previously described. Whether glial cell density varies accordingly is unknown; thus the aim of this study was to estimate glial cell density for the genu, body and splenium -the three main regions of CC-, of P6 and P30 rats. Here we report that the density of CC glial cells reduced by ~10% from P6 to P30. Even so, the density of astrocytes showed a slight increase (+6%), probably due to differentiation of glioblasts. Interestingly, glial cell density decreased for the genu (-21%) and the body (-13%), while for the splenium a minor increase (+5%) was observed. The astrocyte/glia ratio increased (from P6 to P30) for the genu (+27%), body (+17%) and splenium (+4%). Together, our results showed regional differences in glial cell density of the CC. Whether this pattern is modified in some neuropathologies remains to be explored.

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RESUMO

Several changes in brain function, including learning and memory, have been reported during pregnancy but the molecular mechanisms involved in these changes are unknown. Due to the fundamental role of glial cells in brain activity, we analyzed the content of glial fibrillary acidic protein (GFAP) in the hippocampus, frontal cortex, preoptic area, hypothalamus and cerebellum of the rat on days 2, 14, 18, and 21 of pregnancy and on day 2 of lactation by Western blot. A differential expression pattern of GFAP was found in the brain during pregnancy and the beginning of lactation. GFAP content was increased in the hippocampus throughout pregnancy, whereas a decrease was observed in cerebellum. GFAP content was increased in the frontal cortex and hypothalamus on days 14 and 18, respectively, with a decrease in the following days of pregnancy in both regions. In preoptic area a decrease in GFAP content was observed on day 14 with an increase on days 18 and 21. In the frontal cortex and cerebellum, GFAP content was increased on day 2 of lactation, while it was maintained as on day 21 of pregnancy in the other regions. Our data suggest a differential expression pattern of GFAP in the rat brain during pregnancy and the beginning of lactation that should be associated with changes in brain function during these reproductive stages.

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The corpus callosum is a large fiber tract that connects neurons in the right and left cerebral hemispheres. Agenesis of the corpus callosum (ACC) is associated with a large number of human syndromes but little is known about why ACC occurs. In most cases of ACC, callosal axons are able to grow toward the midline but are unable to cross it, continuing to grow into large swirls of axons known as Probst bundles. This phenotype suggests that in some cases ACC may be due to defects in axonal guidance at the midline. General guidance mechanisms that influence the development of axons include chemoattraction and chemorepulsion, presented by either membrane-bound or diffusible molecules. These molecules are not only expressed by the final target but by intermediate targets along the pathway, and by pioneering axons that act as guides for later arriving axons. Midline glial populations are important intermediate targets for commissural axons in the spinal cord and brain, including the corpus callosum. The role of midline glial populations and pioneering axons in the formation of the corpus callosum are discussed. Finally the differential guidance of the ipsilaterally projecting perforating pathway and the contralaterally projecting corpus callosum is addressed. Development of the corpus callosum involves the coordination of a number of different guidance mechanisms and the probable involvement of a large number of molecules.

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RESUMO

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 braims 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 quatified 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 disapperance 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.

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