Navegando por Assunto "Encefalite viral"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Cinética da infecção pelo arbovírus piry em modelo murino: a resposta do hospedeiro adulto
(Universidade Federal do Pará, 2011-09-30) SANTOS, Zaire Alves dos; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
In the present report, a member of a group of RNA South American viruses found in Brazil, that causes febrile disease in humans and encephalitis in neonate and adult murine models, was selected as a model to study encephalitis outcomes in adult albino Swiss mice. In mice housed under standard conditions with free access to water and food, we induced viral encephalitis by intranasal inoculation of Piry virus–infected brain homogenate and correlated neuropathological features. We quantified the cellular inflammatory response in the septal region using a stereologically based unbiased method with clinical signs and neuroinvasion, comparing the outcomes with those of animals inoculated with uninfected brain homogenate. Three-month-old female mice maintained in standard environment received an equal volume of Piry virus infected or normal brain homogenates into the nostrils. From the 1st to 8th days post-instillation (dpi), five subjects from the infected colony were fixed and processed to detect viral antigens and microglia. Control subjects were sacrificed in the 5th dpi and processed for the same markers. After Piry virus encephalitis induced microglial activation and neuroinvasion of glial cells and neurons mainly in the olfactory pathways early in the disease (2 – 4 dpi), but also included hippocampus, cerebellum and brain stem nuclei later on (5 - 8 dpi). The correlation of the host cellular inflammatory quantitative response in the septal area with clinical signs and neuroinvasion, revealed that the number and the morphology of microglias changed early in the disease before neuroinvasion had reached the septal region and clinical signs had appeared. Great variability in clinical symptoms intensity and survival rate were found in the outbred albino Swiss mice strain as compared with previous report in the inbred C57Bl6 strain suggesting less isogenic background. Taken together, our previous and present report dedicated to investigate Piry virus encephalitis progression in the outbred albino Swiss mice strain may open a new field of investigation of the genetics, anatomical and immune substrates of tropical sublethal arbovirus encepahlitis.
Acesso aberto (Open Access)
Encefalite viral induzida pelo vírus da dengue em camundongos suíços albinos: a resposta inflamatória do sistema nervoso central do hospedeiro neonato
(Universidade Federal do Pará, 2011-10-14) TURIEL, Maíra Catherine Pereira; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
To study the innate immune response produced specifically within the developing CNS, avoiding the influence of the immune system, employ viral infection model induced by intracerebral inoculation of dengue virus in neonatal mice. Eight newborn mice two days old of the species Mus musculus and Swiss albino variety were inoculated intracerebrally with brain homogenate infected with Flavivirus species (DENV3 genotype III). Another group of animals was used as control (uninfected) and inoculated with an equal volume of non-infectious brain homogenate and maintained under the same conditions of those infected. After 7 days after infection the mice were sacrificed and patients have had their brains processed for immunostaining of astrocytes and microglia. We quantified the glial and astrocitic immune response in the stratum lacunosum molecular (Lac Mol), radiatum (Rad) and pyramidale (Pir) of hippocampus and in the stratum molecular of dentate gyrus (DGMol) using the optical ractionator to estimate the number of microglias and astrocytes in the hippocampus of infected and control animals. Intense reactive astrocytosis and microglial activation were associated with clinical signs of meningoencephalitis in neonate subjects. Although the number of activated microglia to be higher in infected than in control subjects in the GDMol (Inf:738,95 } 83,07 vs Cont: 232,73 } 70,38; p = 0,0035), Rad (Inf: 392,49 } 44,13 vs Cont: 62,76 } 15,86; p = 0,0004) the number of total microglias (activated or not) was different only in the stratum radiatum (Inf: 6.187,49 } 291,62; Cont: 4.011,89 } 509,73;p = 0,01). On the other hand the total number of astrocytes was higher in control than in infected subjects only in the DGMol (Inf: 8.720,17 } 903,11; Cont: 13.023,13 }1.192,14; p = 0,02). Taken together the results suggest that the immune innate response in neonate mice after encephalitis induced by DENV3 genotype III is associated with a higher increase in the activated microglias than astrocytes in a regional and laminardependent fashion. The patophysiology implications of these events remain to be investigated.
Acesso aberto (Open Access)
Estudo das alterações neuropatológicas e do comportamento em tarefas hipocampo-dependentes induzidas pela encefalite experimental aguda associada ao vírus piry
(Universidade Federal do Pará, 2012-10-05) REIS, Renata Rodrigues dos; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; DINIZ JUNIOR, José Antônio Picanço; http://lattes.cnpq.br/3850460442622655
This study investigated neuropathological changes and behavior in hippocampaldependent tasks induced by encephalitis caused by Piry arbovirus. Three temporal windows (3, 7 and 10 days post infection) and two environmental conditions were assessed to measure possible effects of the environmental enrichment on infection- induced changes. Two months old female mice, maintained in impoverished (IE) or in enriched environment (EE) by six months were tested in burrowing, open field and olfactory discrimination. After this period, all animals were intranasally inoculated with 5 μl of normal (NBH) or infected brain homogenate with Piry arbovirus (PY) and then reorganized into the following groups with seven animals each: IENBH, IEPY, EENBH and EEPY. After three, seven and ten days post instillation (dpi), they were perfused with aldehyde fixative. Their brains were removed, sectioned and the sections were processed either to imunohistochemical with anti-Piry or anti-Iba-1 to marker viral antigens and macrophage/microglial cells, respectively. Stereological quantifications were done in each CA3 layer using the optical fractionator method. Optical fractionator estimations revealed no changes in the number of microglial cells, indicating that this infection was not able to alter the number of cells, but microglia morphology, that revealed a higher number of pro-inflammatory morphological profiles in the IEPY than EEPY. Viral antigens were detected in the olfactory bulb, pyriform cortex, striatum and fimbria, following a sequence that mimics the anatomical olfactory pathway. In IEPY burrowing activity decreased in the first window and remained as such until the last window whereas in EEPY no changes were detected. Immobility increased in IEPY and remained altered until the last window; the number of crossing lines increased in the second and last windows; and the time on the center zone decreased in the second and last windows. In EEPY the immobility increased and correspondently the crossing lines reduced just in the second window. In olfactory discrimination, the main affected group was the IEPY, that didn‟t distinguish the two odors in the last window; in contrast EEPY group remained unaltered.
Acesso aberto (Open Access)
Influências do envelhecimento e do ambiente sobre a progressão da encefalite experimental por arbovírus Piry em modelo murino: mudanças morfológicas microgliais e alterações comportamentais
(Universidade Federal do Pará, 2014-10-03) SOUSA, Aline Andrade de; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
Environmental enrichment and aging effects on behavioral and microglial morphological changes were investigated in a murine model of sub-lethal arbovirus encephalitis. To that end two-months-old female albino Swiss mice were raised in impoverished (IE) or in enriched environments (EE) during 6 (young - Y) or 16 (aged - A) months. After behavioral tests, Y and A mice were nasally instilled with an equal volume of Piry virus infected (Py) or normal brain homogenates. Eight days post-infection (DPI), when behavioral tests first revealed sickness changes, mice brains sections were immunoreacted with anti-IBA1 and anti-Piry virus antibodies. At 20 and 40 dpi, the remaining infected animals were behaviorally re-tested, and processed for the same markers. In infected young mice from impoverished environment (IYPy), burrowing activity decreased and recovered earlier (8–10 dpi) than open field activity (20–40 dpi) but remained unaltered in age-matched mice from enriched environment (EYPy). In contrast, aged infected mice, both from enriched (EAPy) and impoverished (IAPy) environments, reduced significantly burrowing activity at all-time windows. Piry virus encephalitis induced transitory olfactory losses in IYPy and EYPy but permanent in IAPy and EAPy. Piry virus antigens immunolabeling reached a peak in CNS parenchyma at 5 and 6dpi and disappeared at 8dpi. All microglia three-dimensional reconstructions were done at 8dpi. Microglial changes were significantly more severe in young adult than in aged mice but EY mice seem to recover to the microglial homeostatic morphology earlier than IY. EE beneficial effects were smaller in aged mice.