Estresse oxidativo, comportamento e modificações epigenética em modelo animal de hiper-homocisteinemia
Data
2014
Autores
Rezende, Marina Mastelaro de 
Orientadores
D’Almeida, Vânia
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Objetivo: Analisar como o aumento plasmático de homocisteína por diferentes fontes e durações influencia as funções cognitivas, considerando as alterações bioquímicas e epigenéticas decorrentes desse acúmulo em camundongos. Metodologia: Um total de 125 camundongos da linhagem C57Black foi separado em quatro grupos experimentais e seus tratamentos foram mantidos por três diferentes durações, totalizando 12 grupos. Os tratamentos consistiram na adição de L-metionina nas concentrações de 0,5 e 1% (grupos M05 e M1) e DL-homocisteína a 0,09% (grupo H) na água de beber dos animais. Esse procedimento foi mantido por 2, 4 e 6 meses, a fim de se analisar não apenas as respostas aos tratamentos, mas também a influência de sua duração. Em todos os períodos houve também o acompanhamento de animais que não tiveram a água de beber suplementada, como controles (grupo CT). Separados por 1 semana a cada teste, antes do término do final dos tratamentos, os animais foram submetidos aos testes comportamentais: Caixa de atividade, Reconhecimento de objetos novos, Labirinto aquático de Morris e Campo aberto, a fim de se averiguar possíveis alterações cognitivas devidas aos tratamentos. Após os tratamentos e avaliações comportamentais, os animais foram eutanasiados por decapitação e tiveram sangue, cérebro, gordura, coração, fígado e fêmur coletados para os testes relacionados ao balanço redox, epigenética e estado geral dos animais. Os dados são apresentados como média ± desvio padrão. Resultados e conclusões: Os tratamentos foram capazes de aumentar os níveis plasmáticos de homocisteína em relação aos animais CT, porém o perfil de respostas variou conforme tratamento e duração. As quantidades de cisteína plasmática também tiveram um padrão dependente de tratamento e duração. Com estes dados, pode-se concluir que as respostas metabólicas decorrentes da indução de hiper-homocisteinemia são abrangentes e específicas para cada situação. Considerando os marcadores de estresse oxidativo eritrocitários (catalase e superóxido dismutase), aparentemente os tratamentos com metionina têm consequências mais importantes após 2 meses de suplementação, enquanto com homocisteína, 6 meses. Levando em consideração as quantidades de glutationa plasmática e eritrocitária, não parece ter havido influência devida ao tratamento, o que pode ser devido ao diferenciado metabolismo de tióis em roedores. Não houve também alteração dos parâmetros biométricos nos grupos experimentais, o que pode ser devido à magnitude dos aumentos alcançados. Poucas foram as alterações observadas nos testes comportamentais, e elas foram mais devidas a alterações decorrentes do envelhecimento dos animais do que devidas aos diferentes períodos de tratamento. As alterações bioquímicas centrais foram também mais relacionadas ao envelhecimento do que ao tratamento. Pode-se concluir que a indução de hiper-homocisteinemia por diferentes formas de tratamento resulta em modificações bioquímicas e comportamentais específicas ao tipo e duração de cada tratamento.
Objective: The aim of the study was to analyze how the increase in plasma homocysteine levels by different sources and durations influences cognitive functions, considering biochemical and epigenetic changes in response of its increase in mice. Methods: 125 C57Black mice were apart in 4 experimental groups and the treatment was maintained for 3 different durations, performing 12 groups. Treatments consisted in addition of L-methionine in 0.5 and 1% concentrations (M05 and M1 groups) and DL-homocysteine in 0.09% (H group) in drinking water and this procedure were maintained by 2, 4 and 6 months, in order to analyze treatment responses and duration influences. In all periods animals without supplementation in water were followed to serve as control group (CT). Before end of treatments, animals were exposed to behavioral tasks in order to analyze possible cognitive changes due treatment. Each behavioral task was interspace by 1 week and tests applied were: activity box, new object recognition, Morris water maze and open field. After behavioral procedures, animals were euthanized by decapitation and had blood, brain, fat, heart, liver and femur collected for redox status, epigenetics and welfare evaluations. Data are presented as mean ± standard deviation. Results and conclusions: Treatments were effective in increasing plasmatic homocysteine levels in comparison with CT group, but responses were distinct according to each treatment and duration. Plasma cysteine concentrations also presented a treatment and duration variation. Concerning this data, we can conclude that metabolic responses due hiper-homocysteinemia induction are wide and specific depending on the situation. Considering erythrocytes oxidative markers (catalase and superoxide dismutase), methionine treatments had more acute consequences, while homocysteine had more chronic ones. About erythrocyte and plasma glutathione concentrations, there was no significant influence. It can be due to the characteristic thiol metabolism in rodents. Treatments also do not altered biometric parameters which may be due to the relatively low increases achieved. Few changes were observed in behavioral tests, and they were more due to the aging profile of the animals than each treatment period. Central biochemical changes were also more related to aging profile than duration of treatment. We can conclude that hyperhomocysteinemia induced by different treatment profiles produces biochemical and behavioral consequences characteristic of each mechanism it was produced.
Objective: The aim of the study was to analyze how the increase in plasma homocysteine levels by different sources and durations influences cognitive functions, considering biochemical and epigenetic changes in response of its increase in mice. Methods: 125 C57Black mice were apart in 4 experimental groups and the treatment was maintained for 3 different durations, performing 12 groups. Treatments consisted in addition of L-methionine in 0.5 and 1% concentrations (M05 and M1 groups) and DL-homocysteine in 0.09% (H group) in drinking water and this procedure were maintained by 2, 4 and 6 months, in order to analyze treatment responses and duration influences. In all periods animals without supplementation in water were followed to serve as control group (CT). Before end of treatments, animals were exposed to behavioral tasks in order to analyze possible cognitive changes due treatment. Each behavioral task was interspace by 1 week and tests applied were: activity box, new object recognition, Morris water maze and open field. After behavioral procedures, animals were euthanized by decapitation and had blood, brain, fat, heart, liver and femur collected for redox status, epigenetics and welfare evaluations. Data are presented as mean ± standard deviation. Results and conclusions: Treatments were effective in increasing plasmatic homocysteine levels in comparison with CT group, but responses were distinct according to each treatment and duration. Plasma cysteine concentrations also presented a treatment and duration variation. Concerning this data, we can conclude that metabolic responses due hiper-homocysteinemia induction are wide and specific depending on the situation. Considering erythrocytes oxidative markers (catalase and superoxide dismutase), methionine treatments had more acute consequences, while homocysteine had more chronic ones. About erythrocyte and plasma glutathione concentrations, there was no significant influence. It can be due to the characteristic thiol metabolism in rodents. Treatments also do not altered biometric parameters which may be due to the relatively low increases achieved. Few changes were observed in behavioral tests, and they were more due to the aging profile of the animals than each treatment period. Central biochemical changes were also more related to aging profile than duration of treatment. We can conclude that hyperhomocysteinemia induced by different treatment profiles produces biochemical and behavioral consequences characteristic of each mechanism it was produced.
Descrição
Citação
REZENDE, Marina Mastelaro de. Estresse oxidativo, comportamento e modificações epigenética em modelo animal de hiper-homocisteinemia. Dissertação (Mestrado em Ciências) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, 2014.