Navegando por Assunto "Estereologia"

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Acesso aberto (Open Access)
Efeito do extrato aquoso de folhas de mogno (Swietenia macrophylla) em modelo in vivo de doença de Parkinson com lesão com 6-hidroxidopamina
(Universidade Federal do Pará, 2012-09-28) RAMOS, Luciana Fernandes Pastana; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978
Parkinson's disease (PD) is characterized by a progressive degeneration of dopaminergic neurons in the substantia nigra and the presence of classical clinical signs bradykinesia, muscle rigidity, resting tremor and postural instability. The etiology is still unknown and the available treatment options only promote relief of symptoms. Experimental models of PD are fundamental for studies aiming to identify the molecular events involved in the disease and to discover new neuroprotective therapies. This study used a hemiparkinsonism model with lesion induced by 6-hydroxydopamine (6-OHDA), and investigated effects of an aqueous extract of leaves of mahogany (Swietenia macrophylla) on the dopaminergic neurons of the substantia nigra pars compacta (SNpc) and on behavioural parameters assessed in the open-field and apomorphine-induced rotacional tests. The results showed that the 6-OHDA lesioned animals exhibited contralateral rotation induced by apomorphine and significant reduction of dopaminergic neurons in SNpc. However, only 6-OHDA lesioned animals treated with mahogany extract showed significant decrease in relation to the group vehicle/vehicle. There was also a significant decrease in ambulation and rearing in the group 6-OHDA/mahogany. In conclusion, the mahogany extract under the conditions used in the present study potentiated the cytotoxic effect of 6-OHDA and yet promoted worsening of behavioral parameters of the animals.
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)
Enriquecimento ambiental reduz as alterações astrocitárias e a progressão da doença prion em modelo murino: ensaios morfométricos, estereológicos e comportamentais
(Universidade Federal do Pará, 2014-11-26) TORRES NETO, João Bento; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
It is well established that a sedentary lifestyle is a risk factor for a number of chronic diseases, including Alzheimer's disease. The neuropathology of Alzheimer's disease is characterized by amyloid deposits, neuronal loss, reactive gliosis, and vacuolization of the neuropil. Prion disease has been widely used as an experimental model for studying cellular and molecular aspects of chronic neurodegeneration much similar to that described in Alzheimer's disease. The impoverished environment of standard laboratory cages have been used to mimic a sedentary life whereas enriched environment has been used to mimic an active lifestyle. To test the hypothesis that an enriched environment can help to slow down the time course of chronic neurodegeneration associated with prion disease we induced prion disease in twenty Swiss albino female mice which had been housed at six months of age in an enriched environment (EE) or in a standard (SE) environment for five months. After this period bilateral stereotactic intracerebral injection of normal (NBH, n = 10) or infected brain homogenate (ME7, n = 10) were done. Infected brain homogenate was obtained from mice with clinical signs of terminal prion disease. The injected animals returned to their cages and housing conditions and grouped as follow: SE = NBH 5, EE = NBH 5, ME7 SE = 5, ME7 EE = 5. After three weeks post-injections the burrowing test was initiated. Burrowing is a sensitive task to hippocampal damage. 18 weeks after inoculation memory tests of object recognition was carried out. After behavioral tests animals were euthanized and their brains were histologically processed targeting astrocytic immunostaining of areas of interest. The progressive reduction of the activity of burrowing began in the thirteenth week after injection in group ME7 SE but only in the fifteenth week in ME7 EE group. The ability to recognize the displaced object in spatial memory test was impaired in ME7 SE group but remained normal in the other experimental groups. The test of discrimination between the new object and the family revealed no abnormalities. Quantitative analysis of GFAP immunostained cells were performed in the dorsal stratum radiatum of CA3 and in the polymorphic layer of the dorsal dentate gyrus. The stereological estimates of the total number of astrocytes and the volume of the cell body revealed that the number of astrocytes did not change but a significant hypertrophy occurs in CA3 cell bodies of ME7 SE and ME7 EE groups as compared to their respective controls. The average volume of the cell bodies of the ME7 EE group was smaller than that of the group ME7 SE. However similar analysis applied to the polymorphic layer revealed a significant increase in the number of astrocytes in the ME7 SE group in relation to NBH SE group and in ME7 EE compared to NBH EE. The volume of the cell body was also significantly higher in ME7 groups compared to their respective control groups. The three-dimensional morphometric analysis revealed significant increase in volume and surface area of the segments of astrocytic trees in diseased groups compared to controls. Environmental enrichment reduced swelling observed in the branches of ME7 group and increased the number of intersections of the distal branches in NBH EE group relative to NBH SE and the proximal branches in the group ME7 EE compared with ME7 SE. The use of cluster analysis and discriminant allowed the identification of morphometric parameters that contributed most to the distinction between the groups. To test the hypothesis that there are subfamilies of morphologically distinct astrocytes within each experimental group, we applied cluster and discriminant analysis to each experimental group and these analysis resulted in the formation of two distinct families in NBH SE group, three families in NBH EE and ME7 EE groups and four families in the ME7 SE group. The molecular and cellular changes, which lead to the formation of new families of astrocytes, and to the neuroprotection associated with an enriched environment slowing down the progression of the prion disease, remain to be investigated.
Acesso aberto (Open Access)
Ensaios estereológicos e morfologia tridimensional na formação hipocampal de aves migratórias marinhas: análise quantitativa da imunomarcação seletiva de neurônios e micróglia em Calidris pusilla e Actitis macularia
(Universidade Federal do Pará, 2013-08-14) DINIZ, Cristovam Guerreiro; SHERRY, David Francis; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
The aim of this report is to describe the hippocampal formation of two migratory birds, Calidris pusilla and Actitis macularia, that leave the cold regions of the Canadian Tundra, escaping the winter, towards the coast of South America and the Caribbean Islands where they remain until winter ends returning to the Northern hemisphere. We intend to describe the qualitative and quantitative morphological organization of the hippocampal formation, using cytoarchitetonics with cresyl violet and immunostaining for neurons and microglia, followed by stereological estimates of the total number of cells identified with selective markers. We intend as well to compare the three-dimensional morphology of hippocampal microglia of these species with those of the dentate gyrus of Wistar rats and Capuchin monkey. The shorebirds used in the characterization were captured in Canela Island, Bragança City, State of Pará, Brazil (0°47'21.95"S and 46°43'7.34"W), as well as in Canada, in the Bay of Fundy, near Johnson's Mills, New Brunswick (45° 50' 19.3" N 64° 31' 5.39" W). The hippocampal formation limits definition was performed employing Nissl staining and immunostaining for NeuN. For the objects of interest definition of stereological estimates and three-dimensional reconstructions we used immunostaining with anti NeuN for neurons and anti-IBA-1 for microglia respectively. The stereological results revealed similar number of neurons in both species whereas the number of microglia in Actitis macularia was 37% higher than in Calidris pusilla. Furthermore, it was found that the hipocampal formation average volume in Actitis macularia was 38% higher than that found in Calidris pusilla. Comparative studies of the microglial morphology with mammals (Rattus novergicus and Cebus apella) revealed significant morphological differences that indicate microglia in birds shows on average lower complexity (smaller fractal dimension), smaller tree volumes and areas and thinner branches than rat and monkey microglia.
Acesso aberto (Open Access)
Neuroecologia de aves da família charadriidae: estudos arquitetônicos, estereológicos e filogenéticos
(Universidade Federal do Pará, 2017-05-29) PEREIRA, Patrick Douglas Corrêa; DINIZ, Cristovam Guerreiro; http://lattes.cnpq.br/1025250990755299; RÊGO, Péricles Sena do; http://lattes.cnpq.br/2700468443907633
The species Charadrius semipalmatus and Charadrius collaris are from the Plovers group (Charadriidae Family). These species are migratory and non-migratory birds, respectively. In the migratory birds, the hippocampus is important to recover memories related to the stopping places, details about the breeding and the wintering grounds. The hippocampus plays an important role the processing of spatial memory in these organisms, making them excellent models to investigate the effect of behavior in this brain region.This work aims to investigate whether the hippocampal adaptive responses to migratory behavior are related to the migration and/or evolutionary pattern between migrant and non-migrant species of Charadrius genus. The individuals of C. collaris and C. semipalmatus were collected in islands of the coast using mist nets. The birds were measured, anesthetized, identified at species level using morphological features, had samples of muscle tissue collected and were transcardially perfused. The brain was cut in the coronal plane, the sections were stained by the Nissl technique and immunolabelled for NeuN, DCX and C-fos.Cell numbers, hippocampal volume and cell volume were estimated through the Optical Fractionator, Cavalieri Estimator and Nucleator, respectively. The total DNA was extracted for subsequent sequencing of the cytochrome oxidase c subunit I fragment (COI) to generate phylogenetic trees of Bayesian inference, maximum likelihood, genetic distance measurements and analyzes of phylogenetic independent contrasts. The results showed that the anatomy of the hippocampal formations observed in C. semipalmatus and C. collaris corroborate that observed for birds in general.The stereological results evidenced that the migratory species had higher volume of hippocampal formation, number of mature neurons and neurogenesis, when compared to non-migratory species, however there was no difference in the volume of neurons and C-fos positive cells. Molecular results showed no correlation between the characteristics of the hippocampal formation and the evolutionary distances between migrant and non-migrant birds, indicating that the differences in the number of cells as well as the volume of hippocampal formation do not occur due to the phylogenetic distance between the species. Therefore, the existence of neuroanatomic differences in the hippocampal formation of migrant birds is evident, excluding evolutionary factors as responsible for these architectural arrangements.