Marcação imuno-histoquímica da resposta macrofágica e astrocitária no tronco encefálico de ratos Wistar submetidos ao modelo gliotóxico do brometo de etídio e tratados com ciclofosfamida

Abstract

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

Corticosteroids Reduce Glial Fibrillary Acidic Protein Expression in Response to Spinal Cord Injury in a Fetal Rat Model of Dysraphism

“…In the event of an injury astrocytes undergo a range of cellular and biochemical changes required by the healing process [5, 13]. Among other changes, astrocytes grow in number (astrocytosis) and in size (astrogliosis) synthesizing greater amounts of a specific intermediate filament, the main subunit of which is GFAP [5, 6].…”

“…The extent of spinal cord damage may be estimated by the degree of astrocyte activation as evidenced by inflammatory response and glial reaction [5]. Immunostaining for glial fibrillary acidic protein (GFAP), a structural protein present in astrocytes, is a useful method to assess astrocyte proliferation and hypertrophy secondary to nervous system injury [6].…”

Glial reactivity in dogs with visceral leishmaniasis: correlation with T lymphocyte infiltration and with cerebrospinal fluid anti-Leishmania antibody titres

“…These cells respond to lesions by proliferating (astrocytosis) or becoming hypertrophic (astrogliosis), which thus increases the quantity of intermediate filaments and the expression of glial fibrillary acidic protein (GFAP; Summers et al 1995). In cases of brain injury, GFAP expression commonly becomes intense (Sanchez et al 2006) and these cellular alterations are indicative of a brain lesion (Lantos 1990). Increased GFAP expression can be observed in areas that do not exhibit obvious tissue lesions, suggesting that astrocytic alterations are the initial event in the pathological process (Eng and Ghirnikar 1994).…”

Análise do potencial citotóxico agudo da bupivacaína e bupivacaína em excesso enantiomerico de 50% (S75-R25) incorporadas a microesferas sobre o nervo ciático de ratos

“…Presence of inflammatory cells, which would be abundant in case of injury to axons or myelin, was not observed in any of the sections 16 . The absence of visible changes in ultrastructure by day 8 post-injection suggests that there will be no changes when using the same anesthetics on long-term basis.…”