Efeito do Piriproxifeno sobre o desenvolvimento, parâmetros comportamentais e endócrinos em larvas e adultos de Peixe-zebra (Danio rerio)

• Ano de defesa: 2018
• Autor(a) principal: Gusso, Darlan
• Orientador(a): Bonan, Carla Denise
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul
• Programa de Pós-Graduação: Programa de Pós-Graduação em Biologia Celular e Molecular
• Departamento: Escola de Ciências
• País: Brasil
• Palavras-chave em Português: Comportamento; Memória; Larvicida; Piriproxifeno; Peixe-zebra
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::BIOLOGIA GERAL
• Link de acesso: http://tede2.pucrs.br/tede2/handle/tede/7950

Mosquitoes are responsible for the transmission of various pathogens. Over the past three years, the world has witnessed epidemics affecting all age groups, such as dengue fever, yellow fever, chikungunya and zika virus. To control and eliminate Aedes vectors responsible for the transmission of these diseases, it is necessary to use larvicides and insecticides such as pyriproxyfen. Pyriproxyfen is a larvicide used to control mosquitoes, mainly of the genus Aedes. This study evaluated the effects of pyriproxyfen on survival, morphology, behavior, and endocrine parameters at different stages of zebrafish development. We have demonstrated that pyriproxyfen can cause changes in the survival rate, behavior and morphology of exposed larvae, adults exposed at the larval stage, and adult offspring of exposed parents. Larvae exposed to pyriproxyfen for 1-96 hpf (hours post-fertilization) showed a decrease in survival rate, heart rate 3 dpf (days post-fertilization), and body length at 5 and 8 dpf. The distance traveled and the mean velocities of the exposed larvae were reduced in comparison to the vehicle group (1% DMSO). Therefore, pyriproxyfen changes the morphology and behavior of zebrafish in early stages of development and may affect the next generations. However, when the exposed larvae were maintained until the adult stage (6 months), we did not observe differences in locomotor parameters. Parental exposure to pyriproxyfen induced decrease in locomotion of zebrafish adult offspring as well as an anxiolytic-like behavior. We also tested pyriproxyfen exposure for 96 hours in adult zebrafish and the locomotion, anxiety, memory and endocrine parameters were analyzed as well as the gene expression of the glucocorticoid receptor (GR) and corticotropin-releasing factor (CRF). These results showed that there was no significant difference in locomotion, anxiety and endocrine parameters. In addition, there was an impairment of habituation memory in adult zebrafish exposed to pyriproxyfen. Therefore, it is important to control the use of larvicides due to their toxic effects on non-target species. Our findings demonstrated the importance of studies related to the use of larvicides, since they are potential causes of morphological and behavioral alterations in aquatic species, such as zebrafish.