Navegando por Assunto "Agentes neurotóxicos"

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Acesso aberto (Open Access)
Exposição subcrônica de ratos wistar jovens a dose baixa de chumbo induz déficits locomotores e alterações morfológicas associados a estresse oxidativo e disfunção sináptica
(Universidade Federal do Pará, 2018-12-18) PENHA, Luana Ketlen Reis Leão da; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3219037174956649
Lead (PB) is a heavy metal, which can be utilized in the production of several compounds. The main route of human exposure is through the consumption of contaminated food or water, and once absorbed, about 99% of the circulating lead spreads to soft tissues, teeth, bones and brain. In the Central nervous system (CNS), several studies have demonstrated deficits in learning capacity, cognition and intellectual development in humans exposed to lead during a given period of life. However, it is poorly understood the mechanisms of action involved with the toxicity of Pb. From this, this study aimed to evaluate the exploratory, motor and tissue effects induced by the subchronic exposure of young wistar rats to 50 mg/Kg of lead, associated with possible mechanisms of action. Male Wistar rats were exposed for 55 days at a dose of 50mg/Kg of Pb per gavage, and the control animals received distilled water. The open field, inclined plane and route-rod tests were performed for locomotor evaluation. Staining was performed with Hematoxylin and Eosin, as well as immunohistochemistry for the quantification of mature neurons, myelin sheath and synaptic vesicles. To evaluate the protein expression, the Proteomic profile was performed. The statistical analysis was performed by Student's T-Test, being considered significant p < 0.05. After we observed lead deposition only in the cerebellum, it was possible to characterize exploratory and motor deficits in the rats exposed to lead, and we observed a decrease in the number of Purkinje cells, as well as mature neurons, reduction of vesicles synaptic and decreased myelin sheath. In the evaluation of oxidative stress induction, it was possible to evaluate the increase of MDA and nitrite only in the motor cortex. And in the evaluation of protein expression, both regions presented alterations in proteins responsible for the release process of neurotransmitters, as well as receptors and second messengers, and also proteins involved in the process of apoptose. Thus, we conclude that the subchronic exposure to low Pb dose of young Wistar rats promoted locomotor and histological tracings, associated with induction of oxidative stress, alterations in the process of cell signaling, as well as death by apoptosis.
Acesso aberto (Open Access)
Investigação dos efeitos bioquímicos, proteômicos e estruturais da exposição prolongada ao cloreto de mercúrio sobre a medula espinhal de ratos
(Universidade Federal do Pará, 2019-09) CORRÊA, Márcio Gonçalves; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468; https://orcid.org/0000-0003-1486-4013
Mercury chloride (HgCl2) is a pollutant widely found in the environment. This form of mercury is able to promote several damages to the Central Nervous System (CNS), including changes to the motor cortex, an area related to the planning and execution of motor activity. However, the effects of HgCl2 on the spinal cord, an important pathway for the communication between the CNS and the periphery, are still unknown. We exposed adult rats for 45 days to HgCl2, orally, to investigate the effects on oxidative biochemistry, proteomic profile, and spinal cord structures. Our results showed that exposure to this metal promoted increased levels of Hg in the medullary parenchyma, impaired oxidative biochemistry, changes in antioxidant system proteins, energy metabolism and myelin structure; as well as caused disruption in the myelin sheath and reduction in neuronal density. Thus, we conclude that prolonged exposure to HgCl2 triggers biochemical changes and in the expression of several proteins, resulting in damage to the myelin sheath and reduction of neurons in the spinal cord, which may be related to motor damage. Keywords:
Acesso aberto (Open Access)
Potencial neuroprotetor da atividade física em populações ribeirinhas da Amazônia expostas ao mercúrio
(Universidade Federal do Pará, 2025-05) NAZARÉ, Caio Gustavo Leal de; OLIVEIRA, Marcus Augusto de; http://lattes.cnpq.br/6036530007649294; HTTPS://ORCID.ORG/0000-0002-4772-9929; LOPEZ, Maria Elena Crespo; http://lattes.cnpq.br/9900144256348265; https://orcid.org/0000-0002-1335-6853
Mercury is a highly toxic metal and is among the three substances with the greatest potential threat to human health. Its organic form, methylmercury, is particularly dangerous to human health due to its ability to easily cross biological barriers. The brain is a critical target for methylmercury, where it can cause neurological disorders, including motor, visual, auditory, behavioral, and cognitive deficits. Glial cells are closely involved in the mechanisms mediating such disorders and can either protect or damage the central nervous system (CNS), depending on the context. Moreover, no pharmacological treatment has proven effective against mercury intoxication to date, and literature has shown that both physical exercise and physical activity are capable of modulating glial aspects involved in the pathophysiology common to various neurological conditions and methylmercury intoxication. Thus, a potentially therapeutic and non-pharmacological approach, such as physical exercise – and even physical activity – would be particularly suitable for vulnerable populations who are economically, socially, and geographically disadvantaged, such as the riverine communities of the Amazon, who are chronically exposed to methylmercury through the consumption of contaminated fish. This study aims to assess whether physical activity profiles can influence the symptomatology of methylmercury intoxication in riverside residents of the Tucuruí Lake region. Interviews were conducted to obtain a profile of physical activity and self-reported neurological symptoms, and total mercury was measured from hair samples. Our results point to a possible and complex relationship between hair mercury levels and physical activity, suggesting that physical exercise may be a viable alternative to be included in daily life.