Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2390

O Doutorado Acadêmico pertence ao Programa de Pós-Graduação em Neurociências e Biologia Celular (PPGNBC) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA).

Navegar

Agora exibindo 1 - 11 de 11

Acesso aberto (Open Access)
Acidente vascular encefálico isquêmico na exposição crônica ao etanol: estudo pré-clínico da comorbidade e da resposta a minociclina
(Universidade Federal do Pará, 2015-02-27) FONTES JÚNIOR, Enéas de Andrade; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
Stroke is the second largest cause of death in the world and the leading in Brazil, with 87% of strokes due to ischemic processes. Chronic ethanol consumption, usually beginning in adolescence, is recognized as an independent risk factor for increased morbidity and mortality by stroke. Although cases combining the two diseases are relatively common, there is no data in animals or clinical models demonstrating the quality or mechanisms of interaction between the two morbidities, nor its impact on therapeutic intervention. Considering the recent studies proposing minocycline as a new therapeutic tool for the treatment of stroke, this study aimed to investigate the interaction between the Chronic Alcoholic Intoxication (CAI) started in adolescence and the stroke in motor cortex of adult rats, and the effects of treatment with minocycline on this interaction, using behavioral, cellular and molecular parameters. Female Wistar rats (35 days-old) were chronically exposed to ethanol (6.5 g/kg/day, 22.5% w/v) or water for 55 days. One day after the end of the CAI focal ischemia was induced in motor cortex with the endothelin-1 (ET-1), followed by seven-day treatment with minocycline or saline. After this period, the animals were assayed with open field and rota rod tests. Immediately, animals were sacrificed and cortex was dissected for evaluation of nitrite and lipid peroxidation levels. In all groups, some animals were perfused and the motor cortex subjected to histological analysis to assess the damage, and immunohistochemical labeling to neuronal death (anti-NeuN), microglial/macrophage (anti-ED1) and astrocytes (anti-GFAP) activation. The ethanol intoxication from puberty to adulthood potentiated the damage caused by stroke, causing major losses in capacity to start and running movements as well as the strength and motor coordination compared to ischemic animals pretreated with water. These manifestations were accompanied by increased neuronal loss, reduced ED-1+ and GFAP+ cells and higher levels of nitrite and lipid peroxidation. Treatment with minocycline was effective in preventing/reverse motor deficits and tissue damage induced by focal ischemia, also inhibiting the increase in oxidative stress markers. The CAI either alone with succeeded by focal ischemia, harmed the outcome of treatment with minocycline. Our results indicate that heavy alcohol intoxication during adolescence exacerbates the motor deficit and tissue damage in animals subjected to focal ischemia. This process appears to be associated with microglia/astroglial activation, but mainly with oxidative stress. It also shows that the previous history of CAI started adolescence interferes significantly in the treatment of cerebral ischemia with minocycline.
Acesso aberto (Open Access)
Análise de parâmetros de exposição mercurial, suscetibilidade genética e intoxicação em populações ribeirinhas do Tapajós e Tucuruí
(Universidade Federal do Pará, 2016-08-30) ARRIFANO, Gabriela de Paula Fonseca; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
Mercury is a heavy metal responsible for intoxications worldwide. Most toxic form is methylmercury that has affinity for the central nervous system, with recognized neurotoxicity. Some regions of the Amazon are well characterized by mercury exposure in humans, as the region of the Tapajos, due to local mining activity, for example. However, others, such as Tucuruí, remain virtually unstudied, with only one study in humans to date. In the Amazon, there is a large number of studies showing mercury exposure, however, intoxication and susceptibility studies are far less numerous in the Amazonian populations, and even today, there is no study analyzing simultaneously the three factors. The objective of this study was to determine the exposure (mercury content in the body by using mercury levels in hair samples), the individual susceptibility (genetic predisposition of each individual to suffer a damage because the exposure, using the genotyping of apolipoprotein E) and the intoxication (quantifying the extent of the damage already caused by using biomarkers such as S100B and NSE) in Amazonian riverside populations. Three hundred eighty-eight individuals, selected after inclusion and exclusion criteria were studied. The genotype of apolipoprotein E more frequent was ɛ3/ɛ3, followed by ɛ3/ɛ4. Allelic frequencies were 0.043: 0.784: 0.173 to ε2: ɛ3: ɛ4, respectively. The median level of total mercury in hair was 4.2 μg/g (1.9- 10.2). A significant proportion of participants (24.8%) had mercury levels above 10 μg/g, as recommended by the WHO limit, and 12.8% of participants showed a total content of mercury greater or equal to 20 μg/g. Interestingly, Tucuruí levels were much higher than levels in the Tapajós (area recognized by the presence of mining gold activity). We identified 29% of patients with ApoE4 (considered at risk) and 8 maximum risk individuals (carriers of ApoE4 and mercury content above the limit of 10 μg/g). Moreover, there was a significant difference in mRNA levels of S100B protein between groups exposed to high and low levels of mercury. For the first time, markers of the three spheres of influence in human toxicology (exposure, susceptibility and poisoning) were studied. Our data already support the use of these markers to monitoring the Amazonian populations. This knowledge will assist the development of prevention strategies and making government decisions facing the problem of the impact of the mercury in the Amazon.
Acesso aberto (Open Access)
Análise do efeito tóxico e alterações transcriptomicas de células neuronais e gliais após exposição ao fluoreto
(Universidade Federal do Pará, 2019-05-23) GOMES, Bruna Puty Silva; OLIVEIRA, Edivaldo Herculano Corrêa de; http://lattes.cnpq.br/0094007714707651; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468
Despite being widely used in dentistry for dental carie control, in high amounts fluoride may be associated with side effects of which the best known is dental fluorosis. In addition, studies suggest that even at low concentrations fluoride may exerts toxicity leading to damage on CNS. Functional toxicogenomics analysis of gene profile after exposure to contaminants has been used as a tool for the identification of biomarkers of exposure, as well as for the identification of signaling pathways that may be used for treatment and / or prevention of damage caused by the toxicity of certain compounds. As the molecular mechanism of fluoride toxicity still unknow, analysis of F chronic exposure on gene expression profile of CNS cells are necessary. Here we aimed to show the effect of fluoride exposure of plasma concentration founded on population that used to be exposed to fluoridated drink water, on the main CNS cells. In this way, we have used human cell lineage IMR-32 (neurons) and U87 (glial cells) to analyze parameter of viability, morphology and cell metabolism, ATP-synthesis, oxidative stress, DNA damage and global gene expression profile after 10 days exposure. Our results have shown that fluoride does not induce changes in IMR-32 cells. On the other hand, it induces cell death by necrosis, increased metabolism, decrease in ATP and GSH / GSSG in U87 cells and DNA fragmentation. The U87 gene expression profile is differentially altered after fluoride exposure, decreasing 1735 genes and an increasing expression of 1047 genes after exposure to 0.095μg / mL and decreasing of 1863 gene expression and increasing of 1023 expression after exposure to 0.22μg / mL. We also highlighted the major molecular pathways altered after exposure, such as the signaling pathway TNF-alpha via NFK-B and mitochondrial process. We also showed genes with significant importance biology (hub genes) such as the genes PTGES3, EP300, CYP1B1, RPS27A. Our results suggests that glial cell are affected by fluorides exposure and mitochondria has a major role on the mechanism of fluoride toxicity.
Acesso aberto (Open Access)
Avaliação dos efeitos decorrentes da exposição ao cloreto de alumínio sobre parâmetros motores, cognitivos e de estresse oxidativo em ratos
(Universidade Federal do Pará, 2018-12-18) FERNANDES, Rafael Monteiro; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/6791765554367432
Aluminum (Al) is the third most abundant metal in the earth's crust, being present in large amounts in soil and water, its high bioavailability makes it an important environmental contaminant. Al is considered a neurotoxic agent and accumulates in the nervous system, being this behavior associated with several neurodegenerative diseases. However, little is known about its effects at doses similar to human consumption in the nervous and biochemical systems. Thus, this study investigated the effects of chronic exposure to aluminum chloride (AlCl3) on cognition, motor behavior and oxidative stress. For this, adult Wistar rats were divided into three groups: Al1 (8.3 mg / kg / day), Al2 (5.2 mg / kg / day) and Control (Distilled water) being exposed orally for 60 days. After the exposure period, behavioral, histological, oxidative stress parameters and quantification of aluminum levels in the blood were performed. There were no changes in motor behavior, there was change in only one exploratory parameter and in cognition. No differences were found in the population of the purkinje neurons between the experimental groups. Exposure to Al increased levels of this metal in the blood, also altering the parameters of oxidative biochemistry. Thus, we can affirm that exposure to Al in rats, at doses equivalent to urban exposure and in potentially safe doses are capable of promoting breakage of blood homeostasis, altering hippocampal biochemical balance, generating a state of oxidative stress and cognitive damage, not being able to promote significant changes in the cerebellum and motor parameters.
Acesso aberto (Open Access)
Avaliação in vitro dos possíveis efeitos citotóxicos, genotóxicos e mutagênicos das drogas antimaláricas artemisinina e artemeter em linfócitos humanos
(Universidade Federal do Pará, 2012-05-25) CARDOSO, Plínio Cerqueira dos Santos; BAHIA, Marcelo de Oliveira; http://lattes.cnpq.br/3219037174956649; BURBANO, Rommel Mario Rodriguéz; http://lattes.cnpq.br/4362051219348099
Artemisinin is a substance extracted from the Chinese plant Artemisia annua L., and widely used in natural medicine for a treatment of various diseases. Artemether is a substance synthesized from artemisinin. These drugs belong to a special group of molecules called sesquiterpene lactones widely administered in the treatment of malaria. Although considered effective anti-malarial drugs, very little is known about the genotoxic and cytotoxic effects of these drugs. Therefore, in the present study, we evaluated the genotoxic, mutagenic and cytotoxic effects of artemisinin and artemether in cultured human lymphocytes using the comet assay, the micronucleus test and a cytotoxicity assay for detection of necrosis and apoptosis by fluorescent differential acridine orange/ethidium bromide (LA/BE), respectively. Our results showed a significant increase (p<0.05) in the rate of DNA damage measured by comet assay and in the micronucleus frequency after treatment with both drugs. It was also observed that only artemisinin induced a statistically significant increase (p<0.05) in the number of lymphocytes with death by necrosis 48 h after treatment. Thus, it was shown in our work that these two drugs exert mutagenic, genotoxic and cytotoxic effects in cultured human lymphocytes under the conditions evaluated. Our data indicate the need for caution in the use of such drugs, since genotoxic/mutagenic effects may increase the risk of carcinogenesis.
Acesso aberto (Open Access)
Exposição à concentração subletal de metilmercúrio: genotoxicidade e alterações na proliferação celular
(Universidade Federal do Pará, 2015-04-01) MALAQUIAS, Allan Costa; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
Mercury is a metal that stands out from the rest for present liquid under normal temperature and pressure. This xenobiotic is the largest source of pollution in many parts of the world and has been characterized toxic to the central nervous system (CNS). After dumping in liquid form directly into soil and riverbed, this heavy metal complex with various organic elements or it is converted to methylmercury (MeHg) by aquatic microbiota. The MeHg can move up the food chain, an event known as biomagnification, which directly affects human life. Thereby, the Amazon stands out for having all the components necessary for the maintenance of biogeochemical cycle of mercury as well as populations chronically exposed with this heavy metal. And this metal is considered a public health problem. It is well known that this xenobiotic after acute exposure to high doses promotes disorders related to the emergence of degenerative processes in the CNS, however, the effects at low concentrations are not yet fully described. Despite this cell type play an important role in the mercury intoxication process, the role of this metal on glial cells is not well known, especially on the genome and cell proliferation. Thus, this study aimed to evaluate the effect of exposure to this xenobiotic at low concentration on DNA and cell proliferation in C6 glial lineage cells. The biochemical (mitochondrial activity - measured by MTT assay -) and morphofunctional evaluations (membrane integrity - measured by the assay with dyes and AA BE -) confirmed the absence of cell death after exposure to heavy metals in a concentration of 3 μM for 24 hours. Even without causing cell death processes, the treatment with sublethal concentration of MeHg that was able to significantly increase the levels of markers of genotoxicity (DNA fragmentation, micronuclei, nuclear nucleoplasmic bridges and nuclear bud). At the same time, it was possible to observe a change in the cell cycle by increasing the mitotic index and a change in the cell cycle profile with increased cell population in S and G2 / M phases, suggesting an arrest cell cycle arrest. This change in cell cycle caused by MeHg exposure was followed by number of viable cells and cell confluence decrease, 24 hours after the withdrawal of MeHg of culture medium. The C6 cell line culture in addition showed an increase on doubling time parameter. This study demonstrates for the first time exposure to methylmercury low and sublethal concentration can promote genotoxic events and disturbances in cell proliferation in glial cell origin.
Acesso aberto (Open Access)
Intoxicação crônica experimental com alumínio: padrões degenerativos, comportamentais e terapia experimental com magnésio após lesão hipocampal
(Universidade Federal do Pará, 2013-01-17) SILVA JÚNIOR, Ademir Ferreira da; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Experimental evidence suggests that aluminum is a neurotoxic agent with harmful effects on cognitive processes. In this study, we investigated the behavioral, biochemical and histopathological effects of chronic intoxication with aluminum citrate on the hippocampus of adult rats, in the same time investigated experimental therapy treatment with magnesium for reversing the neuropathological changes. We used 70 male Wistar rats of 200-250 g that were divided in groups as follows: control, sodium citrate (CNa), aluminum citrate (CAl), aluminum citrate + magnesium sulphate (CAl+Mg), sodium citrate + sulfate magnesium (Mg+CNa). The dose used of aluminum citrate was 100 mg/kg and 250 mg/kg of magnesium sulfate. The neurotoxic compound was taken orally for 30 days. The animals were subjected to behavioral tests of open field, Rota Rod, social recognition and the elevated T maze (LTE). Furthermore, aluminum levels in plasma and hippocampus of animals was found by atomic absorption spectrometer graphite furnace (GF AAS), biochemical analysis, histopathology and immunohistochemistry for GFAP. It was found that the CAl group showed increase locomotor activity in the open field test compared to the control group, and CAl+Mg group showed a decrease (P <0.001). In memory tests of LTE and social Recognition, the CAl group showed cognitive deficits in relation to other groups, and CAl+Mg group performed well in the test (P <0.001). Aluminum levels found in the hippocampus of CAl group were considerably higher but in the other groups the levels were below to the detection limit of the equipment. Histopathology and imunistochemistry analysis in CAl group showed decreased in cell density and astrocytic reactivity in layers CA1, CA3 and hilus of the hippocampus. These results suggest that the experimental poisoning with aluminum citrate induce deficits of learning and memory and that the administration of magnesium sulphate may have the ability to minimize the damage caused by metal in the hippocampus of intoxicated animals.
Acesso aberto (Open Access)
Modelo experimental de imunossupressão com ciclofosfamida em Rattus norvegicus da linhagem wistar e primatas não humanos da especie Cebus apella: análise genotoxicológica
(Universidade Federal do Pará, 2011-12-23) SOUZA, Patrícia Carvalho de; BURBANO, Rommel Mario Rodriguéz; http://lattes.cnpq.br/4362051219348099
We established a model of immunosuppression in rats by inoculation of the alkylating agent Cyclophosphamide (CY). The administration of 50 mg/kg CY in Wistar rats caused a significant decrease in the parameters of cellularity, and relative weight of lymphoid organs. For analysis of antibody titre of the test on the plaque forming cells and hemolysis test was proven that the humoral immunity of rodents suffered suppression. Four inoculations were carried out and this immunosuppressive intervals between inoculations was determined by recovery of normal levels of the aforementioned parameters. The change in differential counts of white blood cells represented the greatest adverse effect of CY, observed in laboratory parameters analyzed in Cebus apella. Both times it was administered the drug decreased the number of lymphocytes and neutrophils subsequently decreased, but only in the second was observed immunosuppression. Since the phylogenetic proximity of nonhuman primates, this experimental design is of paramount importance for the study of tumors at various stages of development and mainly for testing new drugs and therapeutic regimens. With respect to genotoxicity analysis of CY can conclude that in Wistar rats, the administration of CY significantly increased frequency of micronuclei in polychromatic erythrocytes (MN ECPs) and caused a cytotoxic effect (P <0.05). In C. apella, the peripheral blood lymphocytes after treatment with CY showed a significant increase in media MN/1000 lymphocyte cells compared to control (P <0.05). The concentration of 50mg/kg of CY in C. apella, LD50 is the concentration of the drug, whereas 50% of these animals died during the trial of immunosuppression. Until the development of this work, do not know the concentration corresponding to the LD50 in this species. In comparing the two species of animals used in this work, non-human primates have a more rapid immune recovery compared to rats. Probably the ability to metabolize the drug is more effective in C. apella. Our results support, therefore, that non-human primates are the best experimental models due to its great evolutionary and phylogenetic proximity to humans.
Acesso aberto (Open Access)
Modelo in vitro de parkinsonismo experimental induzido por rotenona: investigação de mecanismos de ação, neuroproteção e morte celular
(Universidade Federal do Pará, 2011-12-29) MARTINS FILHO, Arnaldo Jorge; COSTA, Edmar Tavares da; http://lattes.cnpq.br/6776869402973569; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306
Increasing evidence has suggested a role for environmental factors, such as exposure to pesticides, in the pathogenesis of Parkinson’s disease. In experimental animals the exposure to rotenone, a common herbicide and piscicide, induces features of parkinsonism by inhibiting the activity of mitochondrial complex I. Here we propose to investigate rotenone-induced death of neurons by using primary neuron-enriched and neuron-glia cultures from the rat hippocampus and ventral mesencephalon. The neuronal loss was evaluated with the colorimetric MTT assay. Our results showed significant reduction in the cell viability after exposure to rotenone in a dose- but not in a timedependent manner. We also discovered a remarkable feature of rotenone-induced degeneration of cultured neurons. The higher susceptibility was observed in neuron-glia cultures from the ventral mesencephalon, suggesting that the presence of glia, especially microglia, is an important factor contributing to neurodegeneration. Also, as showed by immunohistochemistry, this type of culture presented the higher density of tirosinahidroxilase (TH)-positive neurons. Mechanistically, our results with calcium blockers showed a minimal role played by external calcium, and an important synergistic influence of the ions from the internal stores in the rotenone-induced neurodegeneration. Indeed, in this study, we report that aqueous extract of mahogany leaves didn’t protect against the rotenone-induced toxicity, in the used concentration; and promoted a synergistic effect when associated with rotenona. Finally, the mahogany leaves extract induced celular death both necrosis and apoptosis. The results of this study should advance our understanding of the mechanism of action for environmental factors in the pathogenesis of Parkinson’s disease.
Acesso aberto (Open Access)
Toxicidade in vitro e in vivo do ortobenzamol, análogo do paracetamol
(Universidade Federal do Pará, 2014-01-23) QUEIROZ, Luana Melo Diogo de; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
Paracetamol (PAR) is the non-prescription medicine most used worldwide. However, high doses of PAR produce hepatic and/or renal toxicity. In order to minimize the toxicity of PAR and get better analgesic and anti-inflammatory activity, a previous study conducted by modifying the chemical structure of PAR through molecular modeling, gave rise to ortobenzamol (OBZ) – analog of PAR. Thus, the OBZ was synthesized and evaluated in models of nociception and inflammation in animals. The study showed central analgesic activity of OBZ, with superior potency when compared to PAR. In addition, tests showed a significant inhibition in the inflammatory process. However, to the OBZ be able to be considered as an important new therapeutic option for the treatment of pain and/or inflammation is necessary to determine its toxicity. Given that, this study aimed to evaluate the toxicity in vitro and in vivo OBZ and compare it with the PAR. For this purpose, in vitro neurotoxicity was evaluated in primary cultures of cortical neurons through cell viability assays, determination of the levels of total and reduced glutathione, as well as the possible neuroprotective capacity against oxidative stress. In vivo studies were performed in mice, initiated by determining the median effective dose (ED50) of PAR in order to compare it with the OBZ at toxicity models studied. It was determined the liver and brain oxidative stress by analyzing the levels of lipid peroxidation and nitrites. The possible hepatic and renal dysfunction was determined by analyzing plasma enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (GGT) levels and creatinine in the blood. We evaluated changes in clinical parameters through the CBC, WBC and platelet parameters and was held to determine the acute toxicity. The results of this study showed that in the tested doses, ortobenzamol is safer than paracetamol. The ortobenzamol displayed absence of neurotoxicity, less hepatotoxic and hematotoxic potential, absence of nephrotoxicity and also was rated as a xenobiotic with low toxicity after evaluation of acute toxicity. Therefore, the ortobenzamol can be considered as a safer alternative to the treatment of pain and inflammation when compared to paracetamol.
Acesso aberto (Open Access)
Triagem de cinco espécies de plantas medicinais usadas na Amazônia através da análise de secreção de histamina
(Universidade Federal do Pará, 2013-12-20) OLIVEIRA, Déborah Mara Costa de; CRESPO LÓPEZ, Maria Elena; http://lattes.cnpq.br/9900144256348265
The World Health Organization recommends the study and use of regional medicinal plants as a source of resources to reduce the costs of public health programs and increase the number of beneficiaries, especially in underdeveloped and developing countries. In the Amazon, the practice of herbal medicine is now an integral part of traditional culture, but on many occasions there is a profound lack of scientific knowledge about the effect of these plants. Therefore it is essential to study the scientific basis or not the indication of these plants for treating or preventing diseases. In this context, allergic diseases are the second leading complication that significantly affects the quality of life. In allergies, mast cells are key effector cells participating through the release of several pro- inflammatory mediators, including histamine. The stabilization of mast cells and thus inhibiting histamine release would be a key factor in the prevention and / or control of allergies. Thus the aim of this study was to evaluate the antiallergic potential of 5 or adapted species from the Amazon Connarus perrottetii var.angustifolius (Radlk) (barbatimão do pará), Fridericia chica (Bonpl.) LG Lohmann (pariri), Luehea speciosa Willd (açoita cavalo), Morinda citrifolia Linn (noni ) and Mansoa alliacea (Lam.) AH Gentry (cipó de alho) through the analysis of histamine secretion. Phytochemical screening of the ethanolic crude extracts to 70 % of each plant (fruit, leaves and / or bark) was performed and evaluated the release of histamine from peritoneal mast cells of rat incubated in vitro with different concentrations of the extracts and / or secretory agents (compound 48 /80 and A23187 ionophore). The present study demonstrates for the first time the inhibitory action of these five medicinal plants on the release of histamine. Among these 5 plants, the extract that showed a more potent effect was peeling Connarus perrottetii var. angustifolius ( Radlk ). Further study of this extract showed a low acute toxicity and lack of genotoxicity, which would support its use as a medicinal plant. The aqueous hexane and ethyl acetate fractions of this extract also showed potent inhibitory effect on histamine release induced. The phytochemical analysis by thin layer chromatography revealed the presence of tannins, catechins and flavonoids that could be responsible for these potent effects Through our results, new scientific bases are formed to elucidate the ethnopharmacological information on herbs traditionally used in the Amazon region. Thus, the possibility of investigating alternative therapies with these extracts against allergic affections or conditions in which the secretion of mast cells is relevant, may especially favor the low-income populations and living in areas with limited access to health centers, as often occurs in the Amazon, but otherwise has direct access to medicinal plants.

Navegar

Navegando Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB por CNPq "CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA::TOXICOLOGIA"