Ação de desreguladores endócrinos em Rana catesbeiana (Anura) em estádio larval e juvenil: efeitos genotóxicos, morfológicos e respostas imunológicas.
Carregando...
Data
2019-03-01
Autores
Gregorio, Lara Salgueiro de
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Os anfíbios são bons indicadores de qualidade ambiental devido a várias características que os tornam suscetíveis a alterações do ambiente. A contaminação aquática, principalmente por desreguladores endócrinos, tem sido apontada como uma causa para o declínio dos anfíbios. O 4-nonilfenol (NP) é um detergente com efeito estrogênico, que já demonstrou efeitos deletérios em alguns grupos de vertebrados. Já o Acetato de Ciproterona (CPA) é um medicamento com propriedade antiandrogênica e, apesar da maioria dos estudos serem com roedores, tem-se observado alto potencial tóxico deste composto. Neste estudo o objetivo foi avaliar os efeitos genotóxicos do NP e do CPA, e sua ação na pigmentação hepática, um biomarcador morfológico de efeito, importante para confirmar a ação dos compostos, além da morfologia gonadal e da contagem leucocitária de girinos e jovens de Rana catesbeiana, em três diferentes concentrações ambientalmente relevantes, após exposição por 28 dias. Nossos resultados mostraram que o NP e o CPA são genotóxicos para os girinos, sendo o CPA de toxicidade muito maior em todas as concentrações, enquanto nos jovens apenas o CPA gerou resposta, nas duas maiores dosagens. Na pigmentação hepática houve aumento apenas nos jovens expostos à concentração média de NP e mínima de CPA. A gônada dos girinos ainda estava indiferenciada, portanto não pode ser avaliada, enquanto na dos jovens não houve alteração na razão sexual nem condições intersexuais. Já o perfil leucocitário variou em ambas as fases. O NP reduziu os linfócitos e aumentou os neutrófilos na dosagem mínima para os girinos, enquanto o CPA aumentou os eosinófilos nas duas maiores concentrações. Nos jovens os neutrófilos reduziram em todos os tratamentos, os trombócitos aumentaram em todos os grupos, exceto na maior dose de CPA, e houve também aumento de basófilos em todos os grupos do CPA. Estes resultados em conjunto nos mostram que ambos os compostos apresentam toxicidade para R. catesbeiana, principalmente citotoxicidade, visto que as principais alterações observadas foram genotóxicas e nas células imunológicas relacionadas à resposta inata. Além disso, houve uma pequena alteração na pigmentação melânica dos jovens, que também está relacionada à defesa. A gônada não apresentou variações, o que pode estar relacionado à alta resistência da espécie. Assim, concluímos que ambos os compostos são tóxicos, mesmo em concentrações muito baixas e em uma espécie resistente como R. catesbeiana, ainda que alguns parâmetros morfológicos não tenham sido alterados. Observamos ainda que a fase de vida pode interferir no grau de resposta aos xenobióticos.
Amphibians are good indicators of environmental quality due to several characteristics that make them susceptible to environmental changes. Aquatic contamination, especially by endocrine disrupters, has been indicated as a cause for amphibian decline. 4-nonylphenol (NP) is a detergent with estrogenic effect, which has already demonstrated deleterious effects in some groups of vertebrates. Cyproterone Acetate (CPA), in turn, has antiandrogenic properties, it is used in medicines, and although most of the studies are with rodents, it has been observed a high toxic potential of this compound. In this study, our aim was to evaluate the genotoxic effects of NP and CPA, and its action on hepatic pigmentation, a morphological biomarker, important to confirm the effects of the compounds, as well as gonadal morphology and leukocyte count of tadpoles and juveniles of Rana catesbeiana, in three different environmentally relevant concentrations, after 28 days exposure. Our results showed that NP and CPA are both genotoxic for tadpoles, but CPA showed much higher toxicity at all concentrations, while in juveniles only CPA increased nuclear abnormalities at the two highest dosages. In hepatic pigmentation there was an increase only in the juveniles exposed to the medium concentration of NP and minimum dosage of CPA. The tadpole gonad was still undifferentiated, so it can not be evaluated, while in the juvenile there was no change in the sex ratio and any intersexual conditions. The leukocyte profile varied in both stages with the treatments. NP reduced lymphocytes and increased neutrophils at minimum dosage for tadpoles, while CPA increased eosinophils at the two highest concentrations. In the juveniles, neutrophils were reduced in all treatments, thrombocytes increased in all groups, except for the highest dose of CPA, and there was also an increase in basophils in all CPA groups. These results, taken together, demonstrate that both compounds are toxic to R. catesbeiana, showing mainly cytotoxicity, since the main alterations observed were genotoxic and in the innate immunological cells. In addition, there was a slight change in melanin pigmentation in juveniles, which is also related to the defense of the organism. The gonad did not vary with treatment, which may be related to the high resistance of the species. Thus, we conclude that both compounds are toxic, even at very low concentrations and in a resistant species such as R. catesbeiana, although some morphological parameters have not been altered. We also observed that the life stage of the animals may interfere with the response to xenobiotics.
Amphibians are good indicators of environmental quality due to several characteristics that make them susceptible to environmental changes. Aquatic contamination, especially by endocrine disrupters, has been indicated as a cause for amphibian decline. 4-nonylphenol (NP) is a detergent with estrogenic effect, which has already demonstrated deleterious effects in some groups of vertebrates. Cyproterone Acetate (CPA), in turn, has antiandrogenic properties, it is used in medicines, and although most of the studies are with rodents, it has been observed a high toxic potential of this compound. In this study, our aim was to evaluate the genotoxic effects of NP and CPA, and its action on hepatic pigmentation, a morphological biomarker, important to confirm the effects of the compounds, as well as gonadal morphology and leukocyte count of tadpoles and juveniles of Rana catesbeiana, in three different environmentally relevant concentrations, after 28 days exposure. Our results showed that NP and CPA are both genotoxic for tadpoles, but CPA showed much higher toxicity at all concentrations, while in juveniles only CPA increased nuclear abnormalities at the two highest dosages. In hepatic pigmentation there was an increase only in the juveniles exposed to the medium concentration of NP and minimum dosage of CPA. The tadpole gonad was still undifferentiated, so it can not be evaluated, while in the juvenile there was no change in the sex ratio and any intersexual conditions. The leukocyte profile varied in both stages with the treatments. NP reduced lymphocytes and increased neutrophils at minimum dosage for tadpoles, while CPA increased eosinophils at the two highest concentrations. In the juveniles, neutrophils were reduced in all treatments, thrombocytes increased in all groups, except for the highest dose of CPA, and there was also an increase in basophils in all CPA groups. These results, taken together, demonstrate that both compounds are toxic to R. catesbeiana, showing mainly cytotoxicity, since the main alterations observed were genotoxic and in the innate immunological cells. In addition, there was a slight change in melanin pigmentation in juveniles, which is also related to the defense of the organism. The gonad did not vary with treatment, which may be related to the high resistance of the species. Thus, we conclude that both compounds are toxic, even at very low concentrations and in a resistant species such as R. catesbeiana, although some morphological parameters have not been altered. We also observed that the life stage of the animals may interfere with the response to xenobiotics.
Descrição
Palavras-chave
EDCs, Genotoxicidade, Melanina, Reprodução, Leucócitos, Genotoxicity, Melanin, Reproduction, Leukocytes