Comportamento rotacional em Teste de Nado Livre como um modelo em roedores para estudo da neurotoxicidade do chumbo durante a vida adulta

• Autor(a) principal: Araujo, Ulisses Cesar de
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12650
• topic: Toxicology; Lead; Free-swimming test; Cerebral asimmetry; Glutathione; Toxicologia; Chumbo; Teste nado livre; Assimetria cerebral; Glutationa; CNPQ::CIENCIAS BIOLOGICAS::FISIOLOGIA::FISIOLOGIA DE ORGAOS E SISTEMAS::NEUROFISIOLOGIA

Lead exposure continues to be a serious public health problem, particularly in developing countries such as Brazil. Despite the increasing number of studies showing neurobehavioral deficits in people occupationally exposed to lead, the mechanisms involved in the manifestation of these problems remain largely unknown. In this sense, the use of animal models opens up the possibility of not only investigating the biological mechanisms associated with lead toxicity but also of elaborating strategies aiming at protecting individuals against its ill effects or even reversing those that already present. Therefore, the main objective of the present work was to assess the potential of the rotatory behavior in the free-swimming test as a rodent model for studying of the neurobehavioral effects adult life lead exposure. In the first study, we analyzed the effect of subchronic lead exposure on motor activity in the freeswimming test and in open-field test, which has been traditionally used to assess the effects of toxic substances on locomotion. While no significant differences were observed between the exposed and control groups in the open-field, in the free-swimming test, lead exposed animals displayed increased natatory activity and fewer spontaneous alterations in the direction of locomotion in comparison with the control group. In the second study, we observed that the magnitude of the effects of lead exposure varied as a function of the consistency of the lateralization, being the results more pronounced in inconsistent animals (lesser degree of lateralization). In both studies, the effects of lead were not dependent on blood levels of lead exposed animals. In the third study, we demonstrated a significant increase in the levels of oxidized glutathione in the brain (indicative of oxidative stress) only in the group of animals that had lead levels above 60 μg/dL. Based in these results, we can conclude that: 1) Rotatory behavior in the free-swimming test constitutes an interesting model for the study of the neurobehavioral effects of lead exposure, 2) Consistency of laterality may be a relevant factor regarding the susceptibility to the toxic effects of lead on the nervous system and 3) The effects of lead are observable in the free-swimming test even at oxidative stress levels that do not affect brain levels of oxidized glutathione.