RESUMO -O gliotóxico brometo de etídio (BE) foi utilizado para o estudo da resposta macrofágica e astrocitária sob imunossupressão com ciclofosfamida (CY). Investigou-se a imunorreatividade astrocitária à proteína glial fibrilar ácida (GFAP) e à vimentina (VIM), e a imunorreatividade macrofágica ao ED1 após injeção do BE. Foram utilizados ratos Wistar adultos injetados na cisterna basal com salina a 0,9% (grupo I), BE a 0,1% (grupo II) e BE a 0,1%, imunossuprimidos com CY (grupo III). Fragmentos do tronco encefálico foram colhidos do 1º ao 21º dia pós-injeção para estudo imuno-histoquímico da GFAP, VIM e ED1. Nos grupos II e III, observou-se imunorreatividade aumentada para GFAP e re-expressão de VIM. No grupo II, células ED1-positivas foram observadas a partir do 2º dia e no grupo III, a partir do 3º dia. Aos 14 dias pós-injeção, havia mais células ED1-positivas no grupo III. A CY aparentemente não alterou a resposta astrocitária. PALAVRAS-CHAVE: desmielinização-remielinização, brometo de etídio, imunossupressão, ED1, GFAP, vimentina.Immunohistochemical staining of the macrophagic and astrocytic response in the brainstem of Wistar rats submitted to the ethidium bromide gliotoxic model and treated with cyclophosphamide ABSTRACT -The gliotoxic ethidium bromide (EB) was used to study morphologically the macrophagic and astrocytic response under immunosuppression by cyclophosphamide (CY). Astrocyte immunoreactivity to glial fibrillary acidic protein (GFAP) and vimentin (VIM) and macrophagic immunoreactivity to ED1 were investigated after EB injection. Male Wistar rats were injected with 0.9% saline solution (group I), 0.1% BE (group II) and 0.1% EB associated with CY treatment (group III). Brainstem samples were collected from the 1 st to the 21 st day post-injection for GFAP, VIM and ED1 immunostaining. In groups II and III, it was observed increased immunoreactivity to GFAP and reexpression of VIM. In group II, ED1-positive cells were noted after the 2 nd day and in group III, after the 3 rd day. On the 14 th day post-injection, it was observed a greater quantity of ED1-positive cells in group III than in group II. Apparently, CY did not change the astrocytic response pattern.KEY WORDS: demyelination-remyelination, ethidium bromide, immunosuppression, ED1, GFAP, vimentin.Mielina é estrutura membranosa característica do tecido nervoso, depositada em segmentos ao longo de fibras nervosas selecionadas e que funciona como isolante a fim de aumentar a velocidade de transmissão do estímulo entre o corpo celular neuronal e seu alvo 1,2 . A ocorrência de desmielinização é observada em muitas doenças de ocorrência espontânea no homem e em outros animais 3 . O brometo de etídio (BE) tem sido usado como droga indutora de desmielinização primária no sistema nervoso central (SNC) 4 e
RESUMO -Uma vez que muitos dos aspectos envolvidos na patogenia dos processos desmielinizantes do sistema nervoso central (SNC) são ainda pouco esclarecidos e que os astrócitos parecem estar envolvidos na mediação de tais processos, este estudo analisou morfologicamente a participação astrocitária na desmielinização do SNC por meio da marcação imunoistoquímica de duas proteínas dos filamentos intermediários astrocitários -a proteína glial fibrilar ácida (GFAP) e a vimentina (VIM) -, comparando amostras de cerebelo e de tronco encefálico de oito cães com cinomose e de dois cães normais, de diferentes raças e com idades entre um e quatro anos. Cortes histológicos dos tecidos foram submetidos à marcação pelo método indireto da avidina-biotina-peroxidase (ABC) e a reatividade astrocitária, observada em microscopia de luz, foi quantificada em um sistema computacional de análise de imagens. Observou-se, na maioria dos cortes de animais doentes, a presença de lesões degenerativas compatíveis com desmielinização. A marcação para a GFAP e para a VIM foi mais intensa nos animais com cinomose do que nos animais normais, especialmente nas regiões circunventriculares e nas adjacentes às áreas de degeneração tecidual. Não houve diferença significativa entre a imunomarcação (GFAP e VIM) dos animais com cinomose com e sem infiltração inflamatória da substância branca do cerebelo. O aumento da imunorreatividade dos astrócitos para a GFAP e a reexpressão de VIM nas áreas lesionais indicam o envolvimento astrocitário na resposta do tecido nervoso às lesões desmielinizantes induzidas pelo vírus da cinomose (CDV) no SNC. PALAVRAS-CHAVE: astrócitos, desmielinização do SNC, cinomose canina, GFAP, vimentina. Immunohistochemical staining of the astrocytic expression of glial fibrillary acidic protein and vimentin in the central nervous system of dogs with canine distemper.ABSTRACT -Considering that many aspects involved in the pathogenesis of the central nervous system (CNS) demyelinating diseases are still poorly understood and that astrocytes seem to mediate such processes, this study analyzed the participation of astrocytes in the demyelinating processes of CNS by using immunohistochemical staining of two astrocytic proteins -glial fibrillary acidic protein (GFAP) and vimentin (VIM) -, comparing samples of cerebellum and brainstem from eight dogs with canine distemper and from two healthy dogs, from different breeds and ages varying from 1 to 4 years old. Histological sections were submitted to the avidin-biotin-peroxidase indirect method of immmunohistochemical staining (ABC) and the astrocytic reactivity, observed in light microscopy, was quantified in a computer system for image analysis. It was possible to notice, on most of the sections from sick animals, degenerative lesions that indicate demyelination. The immunostaining for GFAP and VIM was more intense on animals with canine distemper, specially around the ventricules and near degenerated sites. There was no significant difference between the immunostaining (GFAP and VIM) of...
RESUMO -Introdução: O brometo de etídio (BE) é reconhecido como um agente gliotóxico que causa desaparecimento focal astrocitário e oligodendroglial. Objetivo: Investigou-se a imunorreatividade astrocitária à proteína glial fibrilar ácida (GFAP) e à vimentina (VIM) após injeção do BE. Método: Ratos Wistar adultos foram tomados como controles histológicos (grupo H) ou injetados na cisterna basal com BE a 0,1% (grupo E) ou salina a 0,9% (grupo C). Fragmentos do tronco encefálico foram colhidos das 24 horas aos 31 dias pós-injeção para estudo imuno-histoquímico da GFAP e VIM pelo método da avidina-biotina. Resultados: No grupo E, foram observadas extensas lesões na ponte e no mesencéfalo, com desaparecimento astrocitário da área central 24 horas pós-BE, bem como infiltração macrofágica e astrogliose periférica a partir do 3 o dia. Os astrócitos marginais apresentaram imunorreatividade aumentada à GFAP e reexpressão de VIM, esta confinada às bordas imediatas do sítio lesional. No grupo C, foram visualizadas lesões pontinas discretas, com preservação astrocitária central e marcação menos intensa para GFAP nos bordos em relação ao grupo E. Nenhuma imunorreatividade para VIM foi notada em tais astrócitos. Conclusão: Os astrócitos das margens das lesões induzidas pelo BE apresentaram imunorreatividade aumentada para GFAP e reexpressão de VIM. PALAVRAS-CHAVE: astrócitos, brometo de etídio, GFAP, SNC, vimentina.Investigation into the astrocytic immunoreactivity to GFAP and vimentin in the brainstem of Wistar rats submitted to the ethidium bromide gliotoxic model ABSTRACT -Background: Ethidium bromide (EB) is known as a gliotoxic agent that causes focal astrocytic and oligodendroglial disappearance. Objective: Astrocyte immunoreactivity to glial fibrillary acidic protein (GFAP) and vimentin (VIM) was investigated after EB injection. Method: Adult male Wistar rats were taken as histologic controls (group H) or injected into cisterna pontis with 0.1% EB (group E) or 0.9% saline solution (group C). Brainstem samples were collected from 24 hours to 31 days post-injection for GFAP and VIM immunohistochemical staining using avidin-biotin method. Results: In group E, extensive lesions were seen in the pons and mesencephalon, with astrocyte disappearance from the central area 24 hours post-injection. Macrophagic infiltration and peripheral astrocytic reaction were noted after 3 days. Marginal astrocytes presented increased immunoreactivity to GFAP and reexpression of VIM, the last one confined to the edges of the injury site. In group C, discrete pontine lesions were observed, showing central astrocyte preservation and a peripheral GFAP staining less intense comparing to group E. No immunoreactivity to VIM was noted in such astrocytes. Conclusion: Astrocytes from the edges of the EB-induced lesions presented increased immunoreactivity to GFAP and reexpression of VIM.KEY WORDS: astrocytes, CNS, ethidium bromide, GFAP, vimentin.Os astrócitos constituem as maiores e mais numerosas células gliais presentes no Sistema Nervoso Central (...
Interleukin-15 (IL-15) contributes to natural killer cell development and immune regulation. However, IL-15 and interferon-gamma (IFN-γ) production are significantly reduced during progression to AIDS. We have previously reported that HIV infected chimpanzees (Pan troglodytes) express CD3-CD8+ IFN-γ+ natural killer (NK) cells with an inverse correlation to plasma HIV viral load. To expand on our initial study, we examined a larger population of HIV infected chimpanzees (n=10). Whole blood flow cytometry analyses showed that recombinant gp120 (rgp120) or recombinant IL-15 induces specific CD3-CD8+ IFN-γ+ NK cells at higher levels than CD3+CD8+ IFN-γ+ T cells in HIV infected specimens. Interestingly, peripheral blood T cells exhibited 0.5 to 3% IL-15 surface Tcell/NKT cell phenotypes, and rIL-15 stimulation significantly (P<0.007) up-regulated CD4+CD25+ T cell expression. Importantly, these data demonstrate novel T cell interleukin-15 expression and indicate a plausible regulatory mechanism for this cell-type during viral infection.
We have recently shown that Interleukin-15 (IL-15) plays a crucial role in eliciting interferon-gamma (IFN-γ) production from CD3−CD8+ NK cells in HIV infected chimpanzees (Pan troglodytes). CD3−CD8+ IFN-γ+ NK cells were consistently higher than CD3+CD8+ IFN-γ+ T cells and CD3−CD56+ IFN-γ+ NK cells by flow cytometry analysis. Accordingly, these findings prompted further investigation into the role of IL-15 during HIV infection. Analysis of fresh chimpanzee leukocytes revealed that a rare subpopulation of T cells express surface IL-15. HIV infected chimpanzees were shown express surface IL-15 on < 1 % to 3 % of T cells. Multiparameter flow cytometry analysis utilizing a whole blood system demonstrated that the cells were CD3+CD4+CD16+IL15+ and CD3+CD8+CD16+IL15+ T cells. These populations were shown to be CD25 negative, however, in vitro stimulation of PBMCs with interleukin-15 resulted in upregulation CD4+CD25+ T cells. Additional blood specimens from HIV infected chimpanzees examined during routine physicals also exhibited CD3−CD8+ IFN-γ+ NK cells > CD3+CD8+ IFN-γ+ T cells (p< 0.009, n=10). Research has shown that CD8+ lymphocytes play a substantial role in controlling HIV replication and declining CD4 cells leads to an increase in susceptibility to pathogens. During this study IL-15 was also shown to induce IFN-γ and TNF-α expression from this CD3−CD8+ NK cells. These findings provide additional insights on the influence of IL-15 and chimpanzee resistance mechanisms during HIV infection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.