Navegando por Assunto "Microglia"

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Acesso aberto (Open Access)
Alterações da morfologia da micróglia do septo lateral e comportamento semelhante ao ansioso em um modelo murino de inoculação sequencial de VDEN1 e VDEN4: influência do enriquecimento ambiental
(Universidade Federal do Pará, 2016-05-05) GOMES, Giovanni Freitas; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; SÓSTHENES, Márcia Consentino Kronka; http://lattes.cnpq.br/7881527576747420
Dengue disease is the major cause of deaths by arbovirus infections in Brazil. In the American Continent, the epidemics seem to be associated to the fact that multiple dengue virus (VDEN) serotypes circulate simultaneously. Despite its epidemiological importance and a century of systematic studies dedicated to understand the disease, its detailed pathogenic mechanisms remain poorly understood. The objective of this study was to evaluate possible influence of environmental enrichment on behavioral changes and microglial morphology alterations in the lateral septum after sequential VDEN1 and VDEN4 intraperitoneal inoculations of infected brain homogenates. To that end, we used adult females ten months old of an immunocompetent albino Swiss mouse strain housed in standard or enriched cages. A single intraperitoneal infection of VDEN1 was followed after 28 days by another inoculation of VDEN4. To enhance clinical signs, a regimen of daily alternated injections of VDEN1 or VDEN4 followed 24 hours later by anti-VDEN2 antibody was applied in the last 7 days. Control animals received equal volumes and regime of inoculation of uninfected brain homogenate. We assessed the behavioral changes using the open field exploratory (OF) and elevated plus-maze (EPM). Infected animals housed in standard cages showed significant decrease in time of exploration of the periphery in the OF and in the time of exploration of enclosed arm in the EPM. Uninfected mice housed in standard cages and animal housed in enriched cages did not show same changes. To check how possible microglial changes could be influenced by acute DENV1 infection, secondary DENV4 infection or the passive anti-DENV4 inoculation, we decided to sacrifice groups of animals after which point of inoculation. To evaluate microglial changes, we did selective immunohistochemistry for microglia and macrophages using anti-IBA-1 antibody (Wako, Japan) and we used tri-dimensional reconstruction to morphometric evaluation. Compared to uninfected, infected mice from standard cages showed significant changes in microglial morphology. We also tested the hypothesis that septal microglia is clustered in subtypes and that DENV infection could change this pattern. We noticed microglia is subdivided in three subgroups in physiological conditions, a more complex pattern, a less complex pattern and an intermediate. After DENV1 or DENV4 infection, we observed changes in this pattern, including the appearance of a high complexity cell, increasing the percentage of complexes microglia. We observed these changes in animals from standard cages, but not in animals from enriched cages. Another interesting data is that environmental enrichment appears to reduce this morphometric changes. Based on the evidences, we suggest that sequential infection with VDEN1/VDEN4 in murine model induced behavioral changes and microglial changes in the lateral septum and EA appears to protect animals against these alterations. Based on these evidences, we suggest that microglial from lateral septum present a heterogeneous pattern of morphology and that DENV infection can induce morphological changes, and alterations in the pattern of subdivision, associated with the increase in the percentage of high complexity cells. In addition, infection can induces behavioral changes detected by EPM and OF tests and environmental enrichment seems to protect against microglial and behavioral changes.
Acesso aberto (Open Access)
Atividade antiinflamatória e neuroprotetora da Edaravona no córtex sensóriomotor primário de ratos adultos submetidos à isquemia focal experimental
(Universidade Federal do Pará, 2014-02-12) ARAÚJO, Sanderson Corrêa; BORGES, Rosivaldo dos Santos; http://lattes.cnpq.br/4783661132100859; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke is a neural disorder originated from blood flow decreasing or interruption, making inadequate energy supply in the region, thus promoting tissue damage. The stroke can be divided in hemorragic or ischemic. The ischemic stroke is more prevalent and can occur through thrombosis or embolism. The ischemic pathology has multiple interrelated events like excitotoxicity, peri-infarct depolarization, oxidative and nitrosative stress, inflammation and apoptosis. An element of fundamental importance in ischemic pathology is the microglial cell, whose activity is closely linked to the progression of environment harm. A therapeutic alternative in the treatment of stroke is a pyrazolone called Edaravone. This study evaluated the neuroprotective effect of Edaravone dose of 3mg/kg in primary sensorymotor cortex after focal ischemic lesion. Edaravone treated animals (N = 10) and animals treated with saline solution (N = 10) in the survival time of 1 and 7 days after the ischemic event was evaluated. Treatment whith edaravone showed by histopathological analysis with cresyl violet a reduction of 49% and 66% in infarct size in animals in survival time 1 and 7 days respectively. Immunohistochemistry studies for microglia/macrophages assets (ED1+) demonstrated a reduction in the presence of ED1+ cells in 35% and 41% survival times for 1 and 7 days, respectively. Neutrophils (MBS-1+) were reduced to 64% only in animals with survival times a day. Harmful patterns were assessed qualitatively and quantitatively. Data was tested by ANOVA with Tukey post hoc test. Differences were considered significant at p < 0,05.
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)
Curso temporal da degradação e restauração de redes perineuronais após a ação da enzima chabc entregue via implante de biomembrana no córtex cerebral de ratos
(Universidade Federal do Pará, 2020-03-18) REIS, Rafaela Martins; BAHIA, Carlomagno Pacheco; http://lattes.cnpq.br/0910507988777644; https://orcid.org/0000-0003-3794-4710
The chondroitin sulfate proteoglycans (CSPGs) founded on the extracellular matrix (ECM) of nervous tissue are the main components related to the restriction of neuroplasticity. When condenserd, they form the perineuronal nets (PNNs) and their appearance coincides with the end of the critical period of plasticity and reduction of the reorganization potencial of the central nervous system (CNS). The degradation of PNNs by the enzyme chondroitinase ABC has been used as a tool for reopening periods of neuroplasticity in adult nervous system.. In this work, we analyzed the temporal dynamics of PNNs degradation and restoration in the primary somesthetic cortex (S1) after degradation by the enzyme ChABC in an in vivo experimental model using a biomembrane vehicle for focal delivery and without damaging nervous tissue. In this way, we used adult Wistar rats that were submitted to the implantation of the biomembrane made with ethylene-vinyl-acetate saturated with the enzyme ChABC, with 1, 3 and 7 days of survival time after implantation, using the non implanted side cerebral hemisphere as a control. Our results demonstrated that degradation via implantation of the biomembrane saturated with ChABC was efficient from day 1, with a drastic reduction in the implanted hemisphere (LH) of mature PNNs. There was also a significant increase in the number of immature PNNs in the HD even 7 days after implantation. Neither the biomembrane or the enzyme triggered signs of a neuroinflammatory process or glial activation, but the removal of ECM components interfered with the immunostaining of nerve cells 7 days after the implantation of the biomembrane with ChABC. Therefore, we concluded that the ethylene-vinyl-acetate polymer biomembrane was efficient for focal delivery of the ChABC enzyme and promoted degradation of PNNs in the S1 area of adult rats, did not cause mechanical damage to the nervous tissue, nor activated glial reactivity and the area of enzymatic degradation decreases over time (from 1 to 7 days).
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 da neuropatologia induzida pelo vírus Marabá em modelo murino
(Universidade Federal do Pará, 2014-02-28) FARIAS, Alexandre Maia de; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; DINIZ JUNIOR, José Antônio Picanço; http://lattes.cnpq.br/3850460442622655
The Marabá virus (Be AR 411459) is an Vesiculovirus (VSV), member of the Rhabdoviridae family, isolated in 1983 from a pool of sandflies captured in Marabá - PA by Section Arbovirus the Evandro Chagas Institute. In literature There are few studies on experimental neuropathology Marabá virus induced, despite 30 years of isolation. A single study, however, revealed that viral infection in newborn mice causes necrosis and pyknosis in neurons in several regions of the central nervous system (CNS). The objective of this study was to investigate the distribution of Marabá virus in the CNS, reactive microglia and astrocytes, histopathologic features, and the expression of cytokines and nitric oxide (NO), in Marabá virus-induced encephalitis in BALB / c mice. Thus was performed processing of samples for histopathological examination; Immunohistochemistry for observation of microglia, astrocytes and viral antigen; tests for quantification of cytokines and NO, and statistical analyzes. The results showed that infected animals (Ai) 3 days after inoculation (d.p.i.) with discrete labeling of viral antigen, as well as the activation of microglia and astrocytes in the CNS. Moreover , in Ai 6 d.p.i. marking the viral antigen was observed in almost all brain regions, with intense microglial activation in these locations, although was less astrogliosis. Edema, necrosis and apoptosis of neurons were mainly observed in the olfactory bulb, septum and frontal cortex of Ai 6 d.p.i. Quantification of IL - 12p40, IL- 10, IL- 6, TNF- α, INF- ү, MCP-1 and NO, showed significant increases in Ai 6 d.p.i., when compared with controls animals and Ai 3 d.p.i. On the other hand, TGF-β, important immunosuppressant, has not been significant in all groups and evaluated times (3 and 6 d.p.i.). These results indicate that Marabá virus can infect various CNS regions of BALB /c mouse adult 6 d.p.i., producing anatomical and pathological changes and strong inflammatory immune response that can be lethal to the animal.
Acesso aberto (Open Access)
Fenótipos microgliais e tratamento com minociclina após isquemia focal induzida por microinjeções de endotelina-1 no córtex motor de ratos adultos
(Universidade Federal do Pará, 2016-12-23) DIAS, Michelle Nerissa Coelho; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Microglial cells are fundamental components of the innate immune system that continually make a complete scan of the neural parenchyma in search of subtle tissue changes for the preservation of tissue integrity. These resident macrophages of the central nervous system (CNS) correspond to about 20% of the encephalic cell population. In acute and chronic neural disorders, including brain and spinal cord injury, experimental stroke, Alzheimer's, Parkinson's and Huntington's disease, microglial cells are activated, which is reflected in morphological and biochemical changes. In these diseases, it is believed that microglial activation contributes to both neuroprotection and exacerbation of the injury process. Several experimental evidences suggest that excessive microglial activation may contribute to the increase of the injury process after experimental stroke. However, our previous studies suggest that microglial cells may release trophic factors after experimental stroke in anatomically distinct regions of the microglial population with deleterious phenotypes. There are no studies that have described the reactivity patterns of the different microglial phenotypes after experimental ischemia. In the present project, we will investigate the patterns of activation of microglial cells presenting beneficial and harmful phenotypes, evaluating which microglial populations are inhibited by tetracycline minocycline after focal cortical ischemia. The animals were submitted to focal ischemia in the motor cortex by microinjections of 80 pMol of endothelin-1 (ET- 1). They were sacrificed 7, 14 and 30 days after ischemic induction. The immunohistochemistry technique for the observation of neuronal loss (NeuN +) and double immunofluorescence to evaluate the density of M1 and M2 microglial cells in the lesioned area was used. Statistical analysis of NeuN+ cell density was performed by the Student's t-test from the 7-day of control and treated groups while the analysis of the M1 and M2 microglial cells were done by the analysis of variance in the 07, 14 and 30 control groups, adopting in all tests the level of significance P <0.05. A preservation in the number of neurons in the injured parenchyma of the animals treated with minocycline was confirmed. A decrease in the number of M1 microglial cells in minocycline-treated animals was observed, suggesting that the drug may present effects on expression pathways of M1 microglial phenotypes. However, when the animals of the control group of 07, 14 and 30 are compared, there is an increase in the number of this M1 phenotype that extends from day 7 to day 30. We conclude that there is a neuroprotective effect of the drug minocycline when associated to stroke, suggesting that this drug may be involved in the modulation of microglial phenotypes requiring further studies on its function in the pathways of expression of these phenotypes.
Acesso aberto (Open Access)
Influência do tamanho da ninhada sobre o declínio cognitivo e a morfologia microglial da camada molecular do giro denteado em rattus novergicus
(Universidade Federal do Pará, 2012-10-11) OLIVEIRA, Marcus Augusto de; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; DINIZ JUNIOR, José Antônio Picanço; http://lattes.cnpq.br/3850460442622655
It has been proposed that aging is associated with neuroinflammation in the central nervous system but it is not known whether microglial changes induced by aging are affected by early in life effects of litter size. On the other hand the molecular layer of dentate gyrus has been recognized as the main target of the perforant pathway, whose synaptic integrity is essential for the recognition memories of identity and spatial location. In the present report we investigated if aging cognitive decline and microglial morphological changes in the molecular layer are influenced by litter size changes early in life and aging. To assess these questions Wistar rats suckled in litters of six or 12 pups/mother were raised sedentarily in groups of 2-3 from the 21st post-natal day onwards. At four (mature adult) or 23 (aged) months of age were submitted to spatial memory and object identity recognition tests, sacrificed, perfused with aldehyde fixatives and had their brains processed for selective microglia/macrophages immunolabeling with anti-IBA-1 antibodies. A representative sample of the immunolabeled cells in the molecular layer of dentate gyrus was analyzed after three-dimensional reconstruction with Neurolucida software (Microbright Field Inc.) and morphological features of each cell were quantified by Neuroexplorer (Microbright Field Inc.). It was found that Wistar rats maintained all life in standard laboratory cages showed spatial memory deficits in both mature and aged subjects no matter the litter size. On the other hand all aged subjects independent of the litter size had their object recognition identity memory impaired. Microglial morphological analysis revealed that cell soma area and perimeter and branches volume seem to be more intensely affected by aging and that these changes are mainly associated with animals from large litters. In addition it was observed important shrinkage and thickening of the microglial branches in aged individuals in higher proportion in the group from large litters. Taken together the results suggest that spatial memory seems to be more susceptible to the aging process than object recognition and that these changes are associated with distinct effects on the soma and branching patterns of microglia of molecular layer from young and aged subjects.
Desconhecido
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.
Desconhecido
Influências do tamanho da ninhada e da atividade física sobre a plasticidade glial na formação hipocampal em modelo murino
(Universidade Federal do Pará, 2014-02-07) VIANA, Lane Coelho; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
Previous studies have shown significant effects of perinatal stress on cognitive performance in adulthood and during aging. However remains to be studied in detail as exercise at different stages of life helps to reduce these deficits. This is particularly true if we consider previous descriptions of extracellular matrix and glial cell changes, largely ignored in these studies. Thus, the aim of the present report is to investigate possible influences of litter size and physical activity on object recognition memory at adulthood and whether or not these influences affect glial plasticity and extracellular matrix of the hippocampal formation. To that end, we changed the litter size of Wistar rats to accentuate the degree of competition among siblings by functional teats and decrease the amount of maternal care per individual. During the suckling period, we have quantified the maternal care in litters of different sizes. At various time windows we submitted selected subjects to physical exercise on a treadmill, for 5 weeks, adopting the same training protocol. After exercise, some groups of adults and senile animals were submitted to the hippocampal-dependent object recognition memory test, sacrificed, and processed for selective microglia immunolabeling. Other groups of adult animals not subjected to behavioral tests were also euthanized and had one hemisphere used to record diffusional parameters in the hippocampal parenchyma while the other was used for selective immunolabeling to detect astrocytes, NG2 cells and reelin.We found that an increase in litter size was related to the reduction of maternal care, cognitive decline, altered morphology and proliferation of microglia, astrocytes and NG2 cells, as well as to a change in diffusion patterns in the hippocampal stroma. We also demonstrated that these changes may be reversed, at least partially, by physical activity and the extent of these beneficial effects are more pronounced in younger subjects. Finally, we demonstrated that ageing exacerbates microglial morphological changes induced by increased litter size and reduces memory performance.The molecular mechanisms associated to these effects remain to be investigated.
Acesso aberto (Open Access)
Memória espacial e morfometria tridimensional da micróglia de CA1 e do giro denteado do Cebus apella
(Universidade Federal do Pará, 2013-10-25) SANTOS FILHO, Carlos; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
This study aims to investigate possible correlations between the morphology of microglia in the hippocampus and dentate gyrus and cognitive performances in individual tests of learning and spatial memory in Cebus apella. Due to the good performance of Cebus apella in hippocampal-dependent cognitive tasks, we used selected tests of Cantab battery successfully used in Old World non-human primates and man. To adapt individuals to the touch screen and to assess spatial learning and memory, Motor Screening Test (MOT) and Paired Associated Learning Test (PAL) were used respectively. To detect possible correlations between microglial morphology and individual performances in the spatal learning and memory tasks, it was necessary to reconstruct and analyze microglial morphological details from the middle and outer one-thirds of the dentate gyrus molecular layer and from the lacunosum molecular layer of CA1, employing three dimensional microscopy. The definition of the boundaries and layers of CA1 and dentate gyrus employed architectural criteria previously defined. For selective microglia immunostaining, it was used polyclonal antibody against the adapter binding ionized calcium Iba -1 protein (anti- Iba1). The occurrence of clusters after multivariate statistical analysis based on microglial morphometric parameters allowed the distinction of at least two major morphological groups of microglia in all individuals. The spatial learning rate and some of the morphometric parameters of microglia from dentate gyrus revealed significant linear and non-linear correlations. In contrast, CA1 did not show any correlation between microglial morphology and behavior. Based on the present and previous studies we suggest that the correlation between cognitive performances and complexity of morphological glial features is not an exclusive attribute of astrocytes and that microglial morphology of the molecular layer of dentate gyrus may be indirectly associated to the performance of individual tests of spatial memory.
Desconhecido
Perda neuronal, ativação glial, neurogênese e alterações sensório-motoras após isquemia focal no córtex somestésico de ratos adultos
(Universidade Federal do Pará, 2012-09-26) CORRÊA, Vania Castro; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Stroke is considered one of the most important causes of death and functional deficits in the world. Few neurological conditions are so complex and devastating, resulting in severe neurological deficits and death in the survivors. The cortical regions are commonly affected by stroke, resulting in sensory and motor loss. The establishment of neuropathological patterns in cortical regions, including the somatosensory area, is critical for the investigation of possible therapeutic interventions. In the present study, we investigated the patterns of neuronal loss, microgliosis, astrocytosis, neurogenesis and functional deficits in the primary somatosensory cortex of adult rats submitted to focal ischemia induced by microinjections of 40 pmol of endothelin-1 (ET-1). A total of 30 young adult Wistar rats (Rattus norvegicus) of Wistar, weighing between 250-280g were used in the study. The animals were divided into ischemic (N = 21) and control (N = 9) groups. They were perfused at survival times of 1, 3 and 7 days. The 7 days animals were submitted to behavioral tests to evaluate sensorimotor impairment. Sections were stained with cresyl violet, cytochrome oxidase and immunostained to identify neurons (anti-NeuN), activated and non-activated microglia (Iba-1), activated macrophages/microglia (ED-1), astrocytes (GFAP) and neuroblasts (DCX ). Statistical comparisons between groups were made by one analysis of variance (ANOVA) with Tukey post-hoc test. The animals showed ischemic sensorimotor deficits revealed by Bederson Neurological Scale, Paw Placement and corner tests. Microinjections of ET-1 induced focal ischemic lesion in the primary somatosensory cortex with neuronal loss and progressive astrocytosis and microgliosis mainly in the late survival times. The cytochrome oxidase histochemistry revealed the barrel fields, but unexpectedly marked a population of inflammatory cells with macrophage characteristics in the ischemic region. Increased numbers of SVZ neuroblasts were observed mainly in late survival times of ipsilateral hemisphere in comparison to contralateral side and control animals. There was no significant migration of neuroblasts to the ischemic cortex. The results show that microinjections of ET-1 are an effective method for inducing tissue loss and sensorymotor deficits in the primary somatosensory cortex of adult rats. It was evident that the SVZ is influenced by distant ischemic events distant and that macrophage populations seem to increase the cytochrome oxidase expression. The implemented experimental model can be used in future studies, in which potential neuroprotective drugs can be tested to minimize the described neuropathological alterations.
Acesso aberto (Open Access)
Tratamento com minociclina e transplante intraestriatal de células mononucleares da medula óssea após acidente vascular experimental encefálico
(Universidade Federal do Pará, 2011-04-27) SILVA, Michelle Castro da; FRANCO, Edna Cristina Santos; http://lattes.cnpq.br/5939607544965550; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Several studies suggest that both the semi-synthetic tetracycline minocycline and mononuclear bone marrow cell (BMMCs) transplantation induce neuroprotection in experimental models of stroke. However, a few studies comparatively investigated the effects of these therapeutic approaches following endothelin-1 (ET-1)-induced stroke. In this dissertation, we aimed at investigating the comparative effects of microglial inhibition with minocycline and BMMC transplantation in the acute phase of experimental stroke. Male adult Wistar rats were divided in four experimental groups: saline-treated (N=4), minocyclinetreated (N=4), BMMC-treated (N=4). Behavioral tests were performed at 1, 3 and 7 days post-ischemia to evaluate functional recovery between groups. Animals treated with minocycline received two 50mg/kg (i.p.) doses in the first two days plus five single 25mg/kg (i.p.) daily doses up to sixth days post-ischemia. 1x106 BMMCs were obtained from Wistar rats and directly transplanted into the striatum at 24h post-ischemia. Animals were perfused at 7 days after ischemia onset. Coronal sections were stained with cresyl violet for gross histopathological analysis and immunolabeled for identification of neuronal bodies (NeuN), activated microglia/macrophages (ED1) and apoptotic cells (active caspase-3). Gross histopathological analysis revealed pallor, tissue loss and intense microglial/macrophage activation in ischemic animals treated with sterile saline. BMMC transplantation induced a higher reduction (p<0.05, ANOVA-Tukey) in the number of ED1+ cells than (saline, 276, 3± 9,3;BMMCs, 133,8± 6,8; minocycline, 244,6 ± 7,1). BMMC transplantation and minocycline reduced the infarct area, compared to control, in about 67,75% and 69,1%, respectively, with no statistical differences between treatments (p>0.05). Both treatments afforded comparable levels (p>0.05) of neuronal preservation compared to control (61,3± 1,5; 86,8± 3,4; 81±3,4). BMMC treatment induce a higher decrease in the number of apoptotic cells compared to control and minocycline treatment (26,5± 1,6; 13,1± 0,7; 19,7± 1,1). Both therapeutic approaches improved functional recovery in the ischemic animals. The results suggest that BMMC transplantation is more effective in modulating microglial activation and reducing apoptic cell death than minocycline, although both treatments are equally efficacious on improving neuronal preservation. Future studies should investigate whether minocycline treatment concomitant with BMMC transplantation produces synergistic effects, which might improve neuroprotection.