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Previous issue date: 2012-01-27 / Cadmium is considered the seventh most dangerous substance in the environment and is classified as carcinogen type I, potentially affecting a wide range of living organisms, including humans. In addition to its wide systemic impact and potential lethality, cadmium has been associated to neurobehavioral defects that may also compromise animals ecological status and survival. Despite its potential impact, the comprehension of cellular and molecular mechanisms underlying cadmium deleterious effects on animals behavior is still scarce. This study aimed to evaluate the behavioral effects of cadmium for 1 or 7 days at environmentally relevant concentrations (10 μg/L, 100 μg/L and 1000 μg/L) on zebrafish and to analyze brain oxidative stress and apoptotic markers. Cadmium-exposed zebrafish exhibited a generalized increase in locomotor activity after 1 and 7 days of treatment at all doses in all parameters evaluated, including distance travelled in a 5-min. evaluation period, mean speed and mobile periods. This hyperlocomotory effect significantly compromised animals general performance in exploring a new environment, which was evident in all cadmium exposed animals decreased path efficiency and altered distribution on the water column. Additionally, our results confirmed previous reports of increased oxidative damage in fishes exposed to cadmium and specifically demonstrated higher levels of damaged proteins in brain samples of animals exposed to cadmium at 100 μg/L for 1 day and at 10 μg/L for 7 days when compared to their respective control groups. Lipid peroxidation was also significantly increased in animals brain after 1 day cadmium exposure at 100 μg/L. Real-Time PCR analysis of transcripts for p53 and bax were not altered after 1 day cadmium exposure, but significantly increased after 7 days. Our results present evidence of cadmium deleterious effects on zebrafish cognitive functions and raise attention to the fact that its manifestation appears already after a one day exposure to 10 μg/L, a concentration accepted by most international regulating agencies / O c?dmio ? considerado a s?tima subst?ncia mais perigosa presente no ambiente e ? classificado como carcinog?nico tipo I, potencialmente afetando uma grande quantidade de seres vivos, incluindo os humanos. Ademais, o c?dmio tem sido associado a defeitos neurocomportamentais que podem comprometer o status ecol?gico e a sobreviv?ncia de animais. Apesar do potencial impacto, a compreens?o dos mecanismos celulares e moleculares por tr?s de seus efeitos delet?rios no comportamento de animais ? ainda escassa. Este estudo teve por objetivo avaliar os efeitos comportamentais do c?dmio por 1 e 7 dias a concentra??es relevantes no ambiente (10 μg/L, 100 μg/L and 1000 μg/L) em zebrafish e analisar o estresse oxidativo e marcadores de apoptose no enc?falo. Animais expostos ao c?dmio apresentaram aumento na atividade locomotora ap?s 1 e 7 dias de tratamento em todas as concentra??es e par?metros avaliados, incluindo dist?ncia percorrida num per?odo de 5 minutos, velocidade m?dia e per?odos m?veis. A hiperlocomo??o afetou significativamente o desempenho dos animais em explorar um novo ambiente em todos os grupos tratados, evidenciado por uma diminui??o na efici?ncia de percurso e alterada distribui??o na coluna d ?gua. Adicionalmente, nossos resultados confirmaram estudos pr?vios sobre aumento no dano oxidativo em peixes quando expostos ao c?dmio e especialmente demonstraram n?veis mais elevados de dano a prote?nas em amostras de enc?falo em animais tratados a 100 μg/L por 1 dia e a 10 μg/L por 7 dias quando comparados aos seus respectivos controles. Lipoperoxida??o aumentou significativamente no enc?falo de animais expostos por 1 dia a 100 μg/L. An?lises dos marcadores p53 e bax por Real-time PCR apresentaram nenhuma altera??o ap?s 1 dia de exposi??o, mas significativamente aumentaram ap?s 7 dias. Nossos resultados apresentam evid?ncias dos efeitos delet?rios do c?dmio no comportamento de zebrafish e chama aten??o para o fato de que a manifesta??o de seus efeitos aparece a partir de 1 dia de exposi??o a 10 μg/L, uma concentra??o aceita por muitas ag?ncias de regulamenta??o internacional
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5444 |
| Date | 27 January 2012 |
| Creators | Igansi, Gustavo Nascente |
| Contributors | Vianna, M?nica Ryff Moreira Roca |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
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