Efeitos do Fipronil sobre a sobrevivência e aspectos morfofuncionais da tireoide e suas consequências sobre a metamorfose, morfologia óssea e genotoxicidade em Leptodactylus fuscus e Scinax fuscovarius (Anura).
Data
2022-07-15
Autores
Canevari, Gabriel da Cunha
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A metamorfose em anuros é um processo onde os animais estão extremamente sensíveis, e distúrbios, como os causados por contaminantes, podem levar a alterações fisiológicas e morfológicas irreversíveis. O fipronil é um inseticida que vem gerando muitas preocupações por seus impactos sobre a biodiversidade, uma vez que seu uso vem aumentando muito nos últimos anos. Entre os principais fenômenos durante a metamorfose, há um destaque para a formação e remodelação do sistema esquelético. Assim, devido ao crescente uso do fipronil e ao fato de que a contaminação por esse poderia levar a distúrbios na metamorfose e efeitos deletérios em vários órgãos e sistemas, o objetivo do presente trabalho foi investigar os efeitos do fipronil sobre o desenvolvimento durante a metamorfose, com destaque para o sistema esquelético, avaliando também respostas tóxicas desse composto sobre biomarcadores sanguíneos e hepáticos. Para isso, 48 girinos de Leptodactylus fuscus e Scinax fuscovarius no estágio 28 Gosner foram separados em quatro grupos experimentais (C0: 0,00mg/L; C1: 0,04mg/L, C2: 0,08mg/L e C3: 0,4mg/L de fipronil). Ao atingirem o estágio 46 Gosner, foram eutanasiados, pesados e tiveram sangue e o fígado retirados (para as análises toxicológicas), sendo os animais diafanizados (para a análise do sistema esquelético). Com relação ao desenvolvimento, a exposição ao fipronil levou à uma alteração no tempo de metamorfose e a um atraso no processo de ossificação, não influenciando a massa corpórea e o índice hepatossomático em ambas as espécies, entretanto, levou a uma diminuição no tamanho corporal e no comprimento de alguns ossos do apêndice locomotor posterior de L. fuscus. Com relação a toxicidade, o fipronil não causou efeito genotóxico e levou a um aumento na área de melanina hepática em ambas as espécies, causando um efeito negativo sobre a sobrevivência de S. fuscovarius. Dessa forma concluímos que o fipronil apresenta um potencial em alterar o tempo de metamorfose de anuros e acarreta em um atraso no processo de ossificação; não apresenta efeito genotóxico nas espécies analisadas e gera respostas hepáticas aumentando a atividade dos melanomacrófagos.
Metamorphosis in anurans is a process where animals are extremely sensitive, and disturbances, such as those caused by contaminants, can lead to irreversible physiological and morphological changes. Fipronil is an insecticide that has generated many concerns due to its impacts on biodiversity, since its use has increased greatly in recent years. Among the main phenomena during metamorphosis, there is an emphasis on the formation and remodeling of the skeletal system. Thus, due to the increasing use of fipronil and the fact that its contamination could lead to disturbances in metamorphosis and deleterious effects on various organs and systems, the aim of the present work was to investigate the effects of fipronil on development during metamorphosis, with emphasis on the skeletal system, also evaluating toxic responses of this compound on blood and hepatic biomarkers. For this, 48 tadpoles of Leptodactylus fuscus and Scinax fuscovarius at stage 28 Gosner were separated into four experimental groups (C0: 0.00mg/L; C1: 0.04mg/L, C2: 0.08mg/L and C3: 0. 4mg/L of fipronil). Upon reaching stage 46 Gosner, they were euthanized, weighed and had their blood and liver removed (for toxicological analyses), and the animals were diaphanized (for analysis of the skeletal system). Regarding development, exposure to fipronil led to a change in metamorphosis time and a delay in the ossification process, not influencing body mass and hepatosomatic index in both species, however, it led to a decrease in body size and in the length of some bones of the posterior locomotor appendix of L. fuscus. Regarding toxicity, fipronil did not cause a genotoxic effect and led to an increase in the hepatic melanin area in both species, causing a negative effect on the survival of S. fuscovarius. Thus, we conclude that fipronil has the potential to change the metamorphosis time of anurans and causes a delay in the ossification process; it has no genotoxic effect on the analyzed species and generates hepatic responses by increasing the activity of melanomacrophages.
Metamorphosis in anurans is a process where animals are extremely sensitive, and disturbances, such as those caused by contaminants, can lead to irreversible physiological and morphological changes. Fipronil is an insecticide that has generated many concerns due to its impacts on biodiversity, since its use has increased greatly in recent years. Among the main phenomena during metamorphosis, there is an emphasis on the formation and remodeling of the skeletal system. Thus, due to the increasing use of fipronil and the fact that its contamination could lead to disturbances in metamorphosis and deleterious effects on various organs and systems, the aim of the present work was to investigate the effects of fipronil on development during metamorphosis, with emphasis on the skeletal system, also evaluating toxic responses of this compound on blood and hepatic biomarkers. For this, 48 tadpoles of Leptodactylus fuscus and Scinax fuscovarius at stage 28 Gosner were separated into four experimental groups (C0: 0.00mg/L; C1: 0.04mg/L, C2: 0.08mg/L and C3: 0. 4mg/L of fipronil). Upon reaching stage 46 Gosner, they were euthanized, weighed and had their blood and liver removed (for toxicological analyses), and the animals were diaphanized (for analysis of the skeletal system). Regarding development, exposure to fipronil led to a change in metamorphosis time and a delay in the ossification process, not influencing body mass and hepatosomatic index in both species, however, it led to a decrease in body size and in the length of some bones of the posterior locomotor appendix of L. fuscus. Regarding toxicity, fipronil did not cause a genotoxic effect and led to an increase in the hepatic melanin area in both species, causing a negative effect on the survival of S. fuscovarius. Thus, we conclude that fipronil has the potential to change the metamorphosis time of anurans and causes a delay in the ossification process; it has no genotoxic effect on the analyzed species and generates hepatic responses by increasing the activity of melanomacrophages.
Descrição
Palavras-chave
Anuros, Inseticida, Metamorfose, Ossificação, Toxicidade, Anurans, Insecticide, Metamorphosis, Ossification, Toxicity