Exposição aguda e crônica de fipronil em girinos de rã touro (Lithobates catesbeianus): efeitos genotóxicos e morfológicos
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Data
2021-08-05
Autores
Santos, Arleto Tenório dos
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Universidade Estadual Paulista (Unesp)
Resumo
Os agrotóxicos têm sido utilizados em grande escala para garantir a produtividade de diversas culturas no Brasil. O potencial de contaminação dos pesticidas deve-se principalmente ao fato de que a função biocida desses produtos não exercem ação completamente seletiva, mas ampliam-se a quaisquer outras comunidades que tenham contato, podendo introduzir-se direta ou indiretamente em corpos d`água, solo causando a vulnerabilidade de todo o sistema, com danos irreversíveis e em escalas incalculáveis. O uso indiscriminado destes agroquímicos tem resultado em impactos negativos ao ambiente, principalmente com resíduos tóxicos presentes na água, solo, ar, plantas e animais. O fipronil é uma molécula extremamente ativa e um potente desregulador do Sistema Nervoso Central (SNC), um inseticida classificado como altamente tóxico para o meio ambiente com um tempo de meia vida, longo é o mais utilizado no Brasil. Foi realizado um estudo cienciométrico que reuniu os trabalhos toxicológicos que utilizaram a espécie Lithobates catesbeianus (=Rana catesbeiana) como animal modelo experimental nos últimos 10 anos. O objetivo deste estudo foi avaliar os efeitos genotóxicos e morfológicos sistêmicos, tanto de uma exposição aguda quanto crônica de girinos de rã touro, ao fipronil. Expostos a três concentrações diferentes de Regent® 800 WG (80% fipronil), 0,00 (controle), 0,04, 0,08, 0,4 mg/L; e quatro tempos tratamento na pigmentação da cabeça e cauda, o Fipronil induziu uma diminuição do peso individual e da massa hepática ao final dos experimentos, quanto aos índices experimentais: 4, 8, 12 e 16 dias. A pigmentação corporal respondeu diretamente ao tratamento e ao tempo de exposição. Houve uma diminuição dependente do hepatossomático que não variou de acordo com o tratamento. Para os animais expostos e para o grupo controle, a área de melanina hepática aumentou à medida que o tempo de exposição aumentava. O fipronil teve efeitos genotóxicos em girinos Lithobates catesbeianus mesmo após curtos tempos de exposição (por exemplo, 4 e 8 dias), e a principal anormalidade nuclear está nas células anucleadas. Observou-se correlação relevante entre biomarcadores genotóxicos e melanina cutânea e interna. A frequência de anormalidades nucleares está inversamente correlacionada tanto com a área de melanina hepática quanto com a melanina cutânea dos animais. O fipronil tem efeitos sistêmicos distintos sobre girinos com base em sua concentração, bem como em seu tempo de exposição. Alterações (nível de pigmentação e taxa de anormalidade eritrócito) resultam em efeitos morfológicos e fisiológicos, que podem comprometer o comportamento e a sobrevivência dos anuros.
Pesticides have been used on a large scale to ensure the productivity of various crops in Brazil. The potential for pesticide contamination is mainly due to the fact that the biocide function of these products does not exert completely selective action, but is extended to any other communities that have contact, and may be introduced directly or indirectly into water bodies, soil causing the vulnerability of the entire system, with irreversible damage and in incalculable scales. The indiscriminate use of these agrochemicals has resulted in negative impacts on the environment, especially with toxic residues present in water, soil, air, plants and animals. Fipronil is an extremely active molecule and a potent disruptor of the Central Nervous System (CNS), an insecticide classified as highly toxic to the environment with a long, half-life life is the most widely used in Brazil. Was scientometric study was carried out that brought together toxicological studies that used the species Lithobates catesbeianus (=Rana catesbeiana) as an experimental model animal in the last 10 years. The aim of this study was to evaluate the systemic genotoxic and morphological effects of both acute and chronic exposure of bull frog tadpoles to fipronil. Exposed to three different concentrations of Regent® 800 WG (80% fipronil), 0.00 (control), 0.04, 0.08, 0.4 mg/L; and four treatment times in head and tail pigmentation, Fipronil induced a decrease in individual weight and liver mass at the end of the experiments, regarding the experimental indices: 4, 8, 12 and 16 days. Body pigmentation responded directly to treatment and exposure time. There was a hepatosomatic-dependent decrease that did not vary according to treatment. For the exposed animals and for the control group, the hepatic melanin area increased as the exposure time increased. Fipronil has had genotoxic effects on Lithobates catesbeianus tadpoles even after short exposure times (e.g., 4 and 8 days), and the main nuclear abnormality is in anucleated cells. The relevant correlation was observed between genotoxic biomarkers and cutaneous and internal melanin. The frequency of nuclear abnormalities is inversely, correlated with both the area of hepatic melanin and the cutaneous melanin of the animals. Fipronil has distinct systemic effects on tadpoles based on their concentration as well as their exposure time. Changes (level of pigmentation and erythrocyte abnormality rate) result in morphological and physiological effects, which may compromise the behavior and survival of anurans.
Pesticides have been used on a large scale to ensure the productivity of various crops in Brazil. The potential for pesticide contamination is mainly due to the fact that the biocide function of these products does not exert completely selective action, but is extended to any other communities that have contact, and may be introduced directly or indirectly into water bodies, soil causing the vulnerability of the entire system, with irreversible damage and in incalculable scales. The indiscriminate use of these agrochemicals has resulted in negative impacts on the environment, especially with toxic residues present in water, soil, air, plants and animals. Fipronil is an extremely active molecule and a potent disruptor of the Central Nervous System (CNS), an insecticide classified as highly toxic to the environment with a long, half-life life is the most widely used in Brazil. Was scientometric study was carried out that brought together toxicological studies that used the species Lithobates catesbeianus (=Rana catesbeiana) as an experimental model animal in the last 10 years. The aim of this study was to evaluate the systemic genotoxic and morphological effects of both acute and chronic exposure of bull frog tadpoles to fipronil. Exposed to three different concentrations of Regent® 800 WG (80% fipronil), 0.00 (control), 0.04, 0.08, 0.4 mg/L; and four treatment times in head and tail pigmentation, Fipronil induced a decrease in individual weight and liver mass at the end of the experiments, regarding the experimental indices: 4, 8, 12 and 16 days. Body pigmentation responded directly to treatment and exposure time. There was a hepatosomatic-dependent decrease that did not vary according to treatment. For the exposed animals and for the control group, the hepatic melanin area increased as the exposure time increased. Fipronil has had genotoxic effects on Lithobates catesbeianus tadpoles even after short exposure times (e.g., 4 and 8 days), and the main nuclear abnormality is in anucleated cells. The relevant correlation was observed between genotoxic biomarkers and cutaneous and internal melanin. The frequency of nuclear abnormalities is inversely, correlated with both the area of hepatic melanin and the cutaneous melanin of the animals. Fipronil has distinct systemic effects on tadpoles based on their concentration as well as their exposure time. Changes (level of pigmentation and erythrocyte abnormality rate) result in morphological and physiological effects, which may compromise the behavior and survival of anurans.
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Palavras-chave
Anfibios anuros, Biomarcadores, Pigmentação corporal, Melanina, Melanomacrófagos, Anuran amphibians, Biomarkers, Body pigmentation, Melanomacrophages