Reduction of astrogliosis and microgliosis by cerebrospinal fluid shunting in experimental hydrocephalus

Miller, Janet M.; McAllister, James P.

doi:10.1186/1743-8454-4-5

Cited by 98 publications

(87 citation statements)

References 64 publications

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“…The ability of astrocytes to cause cerebral vasodilation and its antioxidant properties make it a candidate to compensate for the increased intra-cerebral pressure and generation of reactive oxygen species which are synonymous with kaolin-induced hydrocephalus. Reactive gliosis is a known manifestation of hydro- cephalus which is amenable to shunting thereby associating it with the ventriculomegaly of hydrocephalus [19,20] . Of note, in our study, the increase in the density of glial cell was significant across the experimental subsets at 4 weeks of induction.…”

Section: Discussionmentioning

confidence: 99%

Cortical Oligodendrocytes in Kaolin-Induced Hydrocephalus in Wistar Rat: Impact of Degree and Duration of Ventriculomegaly

Ayannuga

Naicker

2017

Ann Neurosci

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Background: Oligodendrocytes are critical to the function of the brain. They generate the myelin sheath which ensures saltatory conduction, which is a more energy saving and efficient means of axonal impulse transmission. Ventriculomegaly results in neuronal degeneration and astrogliosis. Purpose: The effect of the degree of ventriculomegaly on oligodendrocyte in kaolin-induced hydrocephalus and the timeline have not been extensively documented, hence this study. Methods: A total of 81 rats that were 3 weeks old were divided into 4 groups each consisting of control and experimental subgroups. Kaolin suspension was intracisternally injected to induce hydrocephalus and the animal sacrificed post-induction at 1, 2, 3, and 4 weeks. Two 1-mm-thick coronal slices at optic chiasma level were fixed in 10% buffered formal-saline and Karnovsky's fixative for light and transmission electron microscopy (TEM), respectively. The former slices were processed and stained with hematoxylin and eosin for glial density, cortical thickness, and oligodendrocyte evaluations. Subcortical white matter region of the latter were processed by conventional techniques for TEM. Results: Compared with their corresponding control rats, thickness of the dorsolateral cortex was significantly reduced across the 2-4 week post-induction (WPI), glial density was significantly increased in the mild and moderate ventriculomegaly subgroups 1 WPI but only in mild ventriculomegaly subset 2 WPI. In the 4 WPI group, there was significant increase in glial density across the 3 ventriculomegaly subsets. Early hydropic changes of oligodendrocytes were noted in the inner pyramidal layer mostly in the 4 WPI experimental rats. Dilation of the endoplasmic reticulum precedes that of mitochondria, while mitochondrial crista disruption was noted in the 3 and 4 WPI rats. The nuclear membrane of the oligodendrocytes was progressively deformed from the 2nd to 4th WPI. Conclusion: This study reported degenerative changes of oligodendrocytes and its organelles in kaolin-induced hydrocephalus. Degeneration was worse with duration and in the deep cortical layers.

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Section: Discussionmentioning

confidence: 99%

Cortical Oligodendrocytes in Kaolin-Induced Hydrocephalus in Wistar Rat: Impact of Degree and Duration of Ventriculomegaly

Ayannuga

Naicker

2017

Ann Neurosci

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“…The reactive astroglial and microglial responses following ventricular enlargement are well described in animals and humans of different ages presenting hydrocephalus [47,48,49,50,51,52]. Atrocytes that were strongly immunostained by GFAP suggested intense cell activation to repair and heal the cerebral parenchyma subjected to different types of aggression.…”

Section: Discussionmentioning

confidence: 99%

Pre- and Postshunting Magnetization Transfer Ratios Are in Accordance with Neurological and Behavioral Changes in Hydrocephalic Immature Rats

et al. 2014

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Hydrocephalus is a common neurological condition in children characterized by an imbalance between the production and absorption of cerebrospinal fluid (CSF), causing abnormal fluid accumulation in the brain cavities. Shunt systems have been used to drain excess CSF and to prevent progressive ventricular enlargement. However, despite improvements in these systems, neurological and structural changes cannot always be reversed. Our aim was to evaluate the magnetization transfer ratio as a biomarker for the effectiveness of a CSF shunt system to treat neurological and behavioral disorders observed in experimental hydrocephalus. Seven-day-old Wistar rats were used in this study. The pups were subjected to hydrocephalus induction via 20% kaolin intracisternal injection. After confirmation of ventriculomegaly by magnetic resonance imaging (MRI), a group of animals underwent placement of a ventriculosubcutaneous shunt (VSS). The reduction in ventricular size in hydrocephalic rats operated with functional VSS was observed as a decrease in ventricular ratio values and preservation of the corpus callosum thickness. Magnetization transfer values were significantly increased and matched to the recovery process of axonal myelination observed based on more-intense blue staining by solochrome cyanin. The histopathological analysis revealed a reduction in reactive astrocytes by means of GFAP immunostaining. The hydrocephalic rats operated with functional VSS also showed significant progress in motor and exploratory activities, similar to the control animals, at the end of the experiment. In conclusion, the VSS system employed 7 days after hydrocephalus induction was able to prevent structural damage and restore the axonal myelination process in periventricular structures by stabilizing and reducing the ventricular enlargement, and the results are in accordance with the magnetization transfer ratio in MRI.

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“…No caso da hidrocefalia experimental, as derivações liquóricas ainda constituem a única opção de tratamento, por questões de ordem prática, ainda que apresentem riscos não desprezíveis de funcionamento inadequado e complicações (MILLER et al, 2007).…”

Section: Biomarcadores Na Hidrocefaliaunclassified

“…Surpreendentemente, considerando o número crescente de estudos relacionados à hidrocefalia experimental nos últimos anos, há poucas descrições publicadas de derivações experimentais (MILLER et al, 2007;ESKANDARI et al, 2012;CASTRO et al, 2012;CATALÃO et al, 2014). A técnica utilizada neste trabalho envolveu uma derivação entre os ventrículos laterais do animal e o espaço subcutâneo criado próximo a sua cauda, que se mostrou simples e confiável (SANTOS et al, 2016).…”

Section: Biomarcadores Na Hidrocefaliaunclassified

“…Estes achados sugerem que de fato houve piora logo após o início do curso da hidrocefalia, mas que o tratamento com a derivação não foi suficiente para normalizar a performance motora dos animais. A avaliação da hidrocefalia por meio de RM constitui o padrão de análise radiológica do encéfalo, tanto na prática clínica quanto nos estudos experimentais encontrados na literatura (DEL BIGIO et al, 1997;DRAKE et al, 2006;GARNE et al, 2010;HU at al., 2011;MILLER et al, 2007). O primeiro parâmetro avaliado neste trabalho foi a razão ventricular, aqui calculada a partir da divisão (ou razão) entre a área do ventrículo lateral no corte coronal médio e a área total do encéfalo no mesmo corte, com o objetivo de comprovar a redução das dimensões ventriculares apos a derivação.…”

Section: 8 Pg/ml)unclassified

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Análise dos efeitos clínico-radiológicos, histopatológicos e bioquímicos da derivação ventrículo-subcutânea na hidrocefalia induzida por caulim em ratos

Santos¹

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AGRADECIMENTOS"Ofereço, a todos que contribuíram para este trabalho, aquele âmago de mim que consegui salvar, de alguma maneira -o coração central que não lida com palavras, não trafica com sonhos e que é intocado pelo tempo, pela alegria, por adversidades." À minha esposa Leila, pelo apoio e amor incondicionais, e meus filhos Maria e Rafael, sem os quais a vida não teria sentido.A todos os meus familiares, especialmente meus pais Celso e Marlei, meus irmãos Patrícia e Fábio, meus sogros Lourival (in memoriam) e Gecilda e meus cunhados, que proporcionaram todas as condições para meu desenvolvimento pessoal e profissional.Ao Prof. Dr. Ricardo Santos de Oliveira, mestre e amigo, com quem aprendo continuamente e cujo exemplo seguirei orgulhosamente. As palavras não são suficientes para agradecê-lo. Introdução.A hidrocefalia é uma doença de complexa fisiopatologia, que não só afeta a dinâmica do líquido cefalorraquidiano (LCR), mas também outras estruturas do sistema nervoso central, e consequentemente pode trazer sequelas graves em crianças. Sua fisiopatologia, principalmente no nível bioquímico-celular, ainda é pouco conhecida. Objetivos. Avaliar aspectos clínicos (ganho ponderal, comportamento motor e memória), radiológicos (razão ventricular e transferência de magnetização), histopatológicos (astrocitose reativa e proliferação celular na matriz germinativa) e bioquímicos (presença de interleucinas inflamatórias no líquor) na fase aguda da hidrocefalia experimental induzida por caulim e o efeito do tratamento com derivação adaptada (ventrículo-subcutânea). Materiais e métodos.Utilizaram-se ratos Wistar com 7 dias de vida, que foram divididos em três grupos: controle sem injeção de caulim (n = 5), hidrocefálico sem tratamento (n=17), e hidrocefálico tratado com derivação ventrículo-subcutâneo (DVSC), a partir do 7 o dia pós-indução (n=24 Introduction. Hydrocephalus is a complex disease, which affects not only cerebrospinal fluid dynamics, but also other cerebral structures, and therefore may result in severe disability for children. Its pathophysiology is still widely unknown, especially on a cellular-biochemical level. Objectives. Assessment of clinical (weight gain, behavior), radiological (ventricular index and magnetization transfer ratio), histopathological (reactive astrocytosis and cell proliferation over the germinal matrix) and biochemical (dosage of inflammatory interleukins) aspects of acute kaolin-induced experimental hydrocephalus and the effects of the treatment with an adapted shunt (ventricular-subcutaneous). Methods. 7-day-old Wistar rats were divided into three groups: untreated hydrocephalic (n=17), hydrocephalic treated with shunt on the 7 th day after induction (n=24) and controls (n=5). Hydrocephalic animals, both treated and untreated, were injected with a 15% kaolin solution on the cisterna magna, to produce hydrocephalus. Results. Weight gain was similar on both hydrocephalic groups but lower than in controls. Motor behavior was also worse than controls for both groups, but treated animal...

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Reduction of astrogliosis and microgliosis by cerebrospinal fluid shunting in experimental hydrocephalus

Cited by 98 publications

References 64 publications

Cortical Oligodendrocytes in Kaolin-Induced Hydrocephalus in Wistar Rat: Impact of Degree and Duration of Ventriculomegaly

Cortical Oligodendrocytes in Kaolin-Induced Hydrocephalus in Wistar Rat: Impact of Degree and Duration of Ventriculomegaly

Pre- and Postshunting Magnetization Transfer Ratios Are in Accordance with Neurological and Behavioral Changes in Hydrocephalic Immature Rats

Análise dos efeitos clínico-radiológicos, histopatológicos e bioquímicos da derivação ventrículo-subcutânea na hidrocefalia induzida por caulim em ratos

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