Avaliação do comportamento emocional de ratos Wistar machos adolescentes expostos a concentrações ambientais de tributilestanho (TBT)
Arquivos
Data
2021-09-29
Autores
Correia, Lucas Vilas Bôas 
Orientadores
Silva, Regina Cláudia Barbosa da
Tipo
Dissertação de mestrado
Título da Revista
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Resumo
O tributilestanho (TBT) é um composto organometálico derivado do estanho, que tem sido amplamente utilizado como biocida na formulação de tintas náuticas, com a finalidade de inibir a incrustação e o crescimento de organismos aquáticos em estruturas submersas na coluna d’água. Embora seja um composto altamente efetivo e econômico, o TBT possui um custo ambiental elevado devido à persistência ambiental e a toxicidade a organismos não-alvos. A principal via de exposição humana a esse poluente é através do consumo de peixes ou frutos do mar contaminados. Devido a sua lipossolubilidade, o TBT consegue atravessar a barreira hematoencefálica e produzir efeitos neurotóxicos, como o aumento do estresse oxidativo, alterações dos níveis de neurotransmissores e mudanças comportamentais. No entanto, há poucas informações sobre os efeitos do TBT no comportamento emocional de mamíferos. Neste contexto, o presente estudo teve por objetivo investigar os efeitos da exposição subcrônica de TBT (solução veículo, 20 ou 600 ng/g; v.o.; N/grupo = 10), durante 30 dias consecutivos em ratos Wistar machos adolescentes do dia pós-natal (DPN) 28 ao 57, na modulação de respostas comportamentais relacionadas à ansiedade e depressão através dos testes do Labirinto em Cruz Elevado (LCE) e do Splash, respectivamente. A fase da adolescência é considerada um período em que ocorre uma maior vulnerabilidade para a expressão destes fenótipos. O ganho de peso corporal e a atividade locomotora no LCE também foram avaliados. No DPN 58 e 59, os ratos foram submetidos aos testes do LCE e Splash, respectivamente. Os resultados mostraram que a exposição subcrônica ao TBT não afetou os parâmetros clássicos analisados no LCE (número de entradas nos braços abertos e fechados, tempo despendido nestes braços, número total de entradas nos dois braços) nem as frequências das medidas etológicas (autolimpeza facial e mergulho da cabeça). No entanto, aumentou a frequência de levantamentos no LCE na concentração de 20 ng/g desse composto. No teste do Splash, cujos parâmetros observados foram latência para o início do comportamento de autolimpeza após os borrifos de uma solução de 10 % de sacarose no dorso do animal e o tempo despendido neste comportamento, os ratos expostos a ambas as concentrações de TBT apresentaram uma redução na duração da autolimpeza sem afetar a latência para iniciar este comportamento. Conjuntamente, esses resultados indicam que a exposição prolongada de ratos ao TBT, na concentração de 20 ng/g induziu comportamento ansiolítico e comportamento do tipo depressivo nas concentrações de 20 e 600 ng/g. Diferentes mecanismos biológicos combinam-se com o período da adolescência aumentando a vulnerabilidade para a expressão desses fenótipos. A atividade locomotora e o ganho de peso corporal também não foram afetados.
Tributyltin (TBT) is an organometallic compound derived from tin, which has been widely used as a biocide in the formulation of antifouling paints in order to inhibit fouling and the growth of aquatic organisms in structures submerged in the water column. Although it is a highly effective and economical compound, TBT has a high environmental cost due to its environmental persistence and toxicity to non-target organisms. The main route of human exposure to this pollutant is through the consumption of contaminated fishes or seafoods. Due to its liposolubility, TBT is able to cross the blood-brain barrier and produce neurotoxic effects, such as increased oxidative stress, changes in neurotransmitter levels and behavior. However, there is a little information about the effects of TBT on mammalian emotional behavior. In this context, the present study aimed to investigate the effects of subchronic exposure to TBT (vehicle solution, 20 or 600 ng/g; V.O.; N/group = 10) for 30 consecutive days in adolescent male Wistar rats from the postnatal day (PND) 28 to 57 in the modulation of behavioral responses related to anxiety and depression through the Elevated Plus Maze (EPM) and Splash tests, respectively. The adolescence phase is considered a period in which there is a greater vulnerability for the expression of these phenotypes. Body weight gain and locomotor activity were also evaluated. On DPN 58 and 59, the rats were submitted to the EPM and Splash tests, respectively. The results showed that subchronic exposure to TBT did not affect the classical parameters analyzed in the EPM (number of entries in the open and closed arms, time spent in these arms, total number of entries in both arms) nor the frequencies of ethological measurements (facial self-grooming and head-dipping). However, it increased the frequency of rearings in the EPM at the concentration of 20 ng/g of the compound. In the Splash test, which parameters observed were latency to start the self-grooming behavior after spraying a 10% sucrose solution on the animal's dorsal coat and the time spent in this behavior, rats exposed to both concentrations of TBT showed a reduction in self-grooming duration without affecting the latency to initiate this behavior. Taking Together, these results indicate that prolonged exposure of rats to TBT at a concentration of 20 ng/g induced anxiolytic-like behavior and depressive-like behavior at concentrations of 20 and 600 ng/g. These different biological mechanisms combine with the period of adolescence, increasing the vulnerability to the expression of these phenotypes. Locomotor activity and body weight gain were also not affected.
Tributyltin (TBT) is an organometallic compound derived from tin, which has been widely used as a biocide in the formulation of antifouling paints in order to inhibit fouling and the growth of aquatic organisms in structures submerged in the water column. Although it is a highly effective and economical compound, TBT has a high environmental cost due to its environmental persistence and toxicity to non-target organisms. The main route of human exposure to this pollutant is through the consumption of contaminated fishes or seafoods. Due to its liposolubility, TBT is able to cross the blood-brain barrier and produce neurotoxic effects, such as increased oxidative stress, changes in neurotransmitter levels and behavior. However, there is a little information about the effects of TBT on mammalian emotional behavior. In this context, the present study aimed to investigate the effects of subchronic exposure to TBT (vehicle solution, 20 or 600 ng/g; V.O.; N/group = 10) for 30 consecutive days in adolescent male Wistar rats from the postnatal day (PND) 28 to 57 in the modulation of behavioral responses related to anxiety and depression through the Elevated Plus Maze (EPM) and Splash tests, respectively. The adolescence phase is considered a period in which there is a greater vulnerability for the expression of these phenotypes. Body weight gain and locomotor activity were also evaluated. On DPN 58 and 59, the rats were submitted to the EPM and Splash tests, respectively. The results showed that subchronic exposure to TBT did not affect the classical parameters analyzed in the EPM (number of entries in the open and closed arms, time spent in these arms, total number of entries in both arms) nor the frequencies of ethological measurements (facial self-grooming and head-dipping). However, it increased the frequency of rearings in the EPM at the concentration of 20 ng/g of the compound. In the Splash test, which parameters observed were latency to start the self-grooming behavior after spraying a 10% sucrose solution on the animal's dorsal coat and the time spent in this behavior, rats exposed to both concentrations of TBT showed a reduction in self-grooming duration without affecting the latency to initiate this behavior. Taking Together, these results indicate that prolonged exposure of rats to TBT at a concentration of 20 ng/g induced anxiolytic-like behavior and depressive-like behavior at concentrations of 20 and 600 ng/g. These different biological mechanisms combine with the period of adolescence, increasing the vulnerability to the expression of these phenotypes. Locomotor activity and body weight gain were also not affected.
Descrição
Citação
CORREIA, Lucas Vilas Bôas. Avaliação do comportamento emocional de ratos Wistar machos adolescentes expostos a concentrações ambientais de tributilestanho (TBT). 2021. 75 f. Dissertação (Mestrado em Bioprodutos e Bioprocessos) - Instituto de Saúde e Sociedade, Universidade Federal de São Paulo, Santos, 2021.