Avaliação da hepatotoxicidade dos poluentes do rio doce através das análises histopatológicas no fígado dos peixes
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2022-02-01
Autores
Onishi, Kaori
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Universidade Estadual Paulista (Unesp)
Resumo
A bacia do rio Doce representa um conjunto de corpos hídricos de grande relevância ambiental e socioeconômica, os quais têm sido cronicamente contaminados por diversas atividades antrópicas. Mais recentemente, o rompimento da barragem de Fundão, em Mariana (MG), liberou enorme quantidade de resíduos de mineração, adicionando uma grande carga de contaminantes em toda a extensão da bacia hidrográfica. Considerando que os contaminantes podem prejudicar a saúde dos peixes nativos, e que nesses organismos o fígado é um órgão alvo de chave no metabolismo dos xenobióticos, este estudo teve como objetivo avaliar a hepatotoxicidade em peixes do Rio Doce através da histopatologia do fígado de indivíduos de diferentes espécies de bagres e cascudos (Rhamdia quelen, Trachelyipterus atriatulus, Pimelodus maculatus, Rineloricaria lanceolata, Glanidium botocudo, Loricaria coximensis, Hypostomus sp., Lophiosilurus alexandri), coletados em 8 localidades distribuídas ao longo da bacia, e em dois períodos diferentes (chuvoso e seco de 2019). Cerca de 15 peixes foram coletados por ponto, pesados, sacrificados e seus fígados foram removidos e fixados. Lâminas preparadas com cortes de 5 µm de espessura e coradas em Hematoxilina/Eosina foram analisadas aleatoriamente por microscopia óptica, seguindo critérios padronizados para identificar e quantificar as alterações histopatológicas, classificadas de acordo com o grau de reversibilidade de cada lesão. Os dados obtidos foram organizados para realizar o teste de normalidade de D’Agostino Pearson e o teste de Kruskal-Wallis. No período chuvoso houve uma maior inconstância nas respostas histopatológicas o que pode ser justificado pela maior diversidade de espécies capturadas. Já no período seco, as respostas histopatológicas foram mais constantes, apresentando altos índices de centros de melanomacrófagos, infiltrações leucocitárias e necrose. No geral, os índices de alterações histopatológicas foram baixos, mas os pontos que apresentaram mais alterações graves como a necrose estavam localizados no alto rio Doce, onde há mais contaminantes inorgânicos. Já no médio e baixo rio Doce, foram observadas uma elevada quantidade de alterações relacionadas ao sistema imune dos indivíduos.
The Doce River basin represents a set of water bodies of great environmental and socioeconomic relevance, which have been chronically contaminated by various human activities. Recently, the rupture of the Fundão dam, in Mariana (MG), released a huge amount of mining waste, adding a large load of contaminants throughout the watershed. Considering that contaminants can harm the health of native fish, and that in these organisms the liver is a key target organ in the metabolism of xenobiotics, this study aimed to evaluate the hepatotoxicity in fish from Rio Doce through the histopathology of the liver of individuals of different species of catfish (Rhamdia quelen, Trachelyipterus atriatulus, Pimelodus maculatus, Rineloricaria lanceolata, Glanidium botocudo, Loricaria coximensis, Hypostomus sp., Lophiosilurus alexandri), collected in 8 locations distributed throughout the basin, and in two different periods (rainy and dry 2019). About 15 fish were collected per point, weighed, sacrificed and their livers were removed and fixed. Slides prepared with 5 µm thick sections and stained in Hematoxylin/Eosin were randomly analyzed by light microscopy, following standardized criteria to identify and quantify histopathological changes, classified according to the degree of reversibility of each lesion. The data obtained were organized to perform the D'Agostino Pearson normality test and the Kruskal-Wallis test. In the rainy season there was a greater inconsistency in the histopathological responses, which can be explained by the greater diversity of species captured. In the dry period, the histopathological responses were more constant, with high rates of melanomacrophage centers, leukocyte infiltration and necrosis. In general, the rates of histopathological alterations were low, but the points that presented more severe alterations such as necrosis were located in the upper Rio Doce, where there are more inorganic contaminants. In the middle and lower Rio Doce, a high amount of alterations related to the immune system of individuals were observed.
The Doce River basin represents a set of water bodies of great environmental and socioeconomic relevance, which have been chronically contaminated by various human activities. Recently, the rupture of the Fundão dam, in Mariana (MG), released a huge amount of mining waste, adding a large load of contaminants throughout the watershed. Considering that contaminants can harm the health of native fish, and that in these organisms the liver is a key target organ in the metabolism of xenobiotics, this study aimed to evaluate the hepatotoxicity in fish from Rio Doce through the histopathology of the liver of individuals of different species of catfish (Rhamdia quelen, Trachelyipterus atriatulus, Pimelodus maculatus, Rineloricaria lanceolata, Glanidium botocudo, Loricaria coximensis, Hypostomus sp., Lophiosilurus alexandri), collected in 8 locations distributed throughout the basin, and in two different periods (rainy and dry 2019). About 15 fish were collected per point, weighed, sacrificed and their livers were removed and fixed. Slides prepared with 5 µm thick sections and stained in Hematoxylin/Eosin were randomly analyzed by light microscopy, following standardized criteria to identify and quantify histopathological changes, classified according to the degree of reversibility of each lesion. The data obtained were organized to perform the D'Agostino Pearson normality test and the Kruskal-Wallis test. In the rainy season there was a greater inconsistency in the histopathological responses, which can be explained by the greater diversity of species captured. In the dry period, the histopathological responses were more constant, with high rates of melanomacrophage centers, leukocyte infiltration and necrosis. In general, the rates of histopathological alterations were low, but the points that presented more severe alterations such as necrosis were located in the upper Rio Doce, where there are more inorganic contaminants. In the middle and lower Rio Doce, a high amount of alterations related to the immune system of individuals were observed.
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Palavras-chave
Histologia, Bagres, Cascudos, Desastre de Mariana, Ecotoxicologia, Água Poluição, Histology, Catfish, Mariana disaster, Ecotoxicology, Aquatic pollution