Toxicidade hepática e renal exercida por mistura de metais em baixas concentrações: estudo experimental em ratos machos
Data
2022-11-29
Autores
D'Assumpção, Thalita Tofanin Sargiani 
Orientadores
Perobelli, Juliana Elaine
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Embora a mineração seja considerada uma atividade de grande importância para o desenvolvimento de uma sociedade, ela está associada a diversos impactos ambientais quando realizada sem planejamento e sem fiscalização adequada. O Brasil exporta diversos produtos de origem mineral, sendo o minério de ferro um dos mais relevantes. Em 2015, ocorreu o rompimento da barragem de rejeitos de mineração de Fundão, localizada em Mariana, Minas Gerais. Esse acidente acarretou diversos danos socioambientais e contaminação ao longo da bacia do Rio Doce por diversos metais como Cádmio (Cd), Chumbo (Pb), Arsênio (As) e Manganês (Mn). Diversos estudos têm investigado a toxicidade exercida por esses metais isoladamente, tanto em humanos quanto em modelos experimentais. Porém, não há estudos com misturas de metais, como aqueles encontrados na água da bacia do Rio Doce após o referido impacto ambiental. Assim, estudos que visem avaliar a toxicidade dessas misturas complexas, especialmente em concentrações ambientalmente referenciadas, se fazem necessários para melhor entendimento das possíveis interações químicas. Nesse contexto, o presente estudo utilizou uma mistura dos metais encontrados em maior concentração na lama proveniente do acidente, i.e., Mn, As, Pb e Cd, visando elucidar seus efeitos adversos sobre a morfofisiologia hepática e renal de ratos machos adultos após a exposição aguda (exposição única e avaliação após 24h) ou subcrônica (exposição por 30 dias) a concentrações ambientalmente relevantes. Os resultados mostraram que os animais expostos agudamente à mistura de metais não apresentaram comorbidades, porém apresentaram alterações histopatológicas importantes no fígado e rins, bem como uma diminuição nos níveis séricos de Alanina transaminase. Já os animais expostos à mistura de metais durante 30 dias (exposição subcrônica) apresentaram alterações transitórias nos parâmetros gerais de saúde, em especial alterações gastrointestinais. Em relação às análises histopatológicas, houve um aumento na ocorrência de alterações morfológicas tanto no fígado quanto no rim, sem alterações significativas em parâmetros bioquímicos. Assim, conclui-se que a exposição à mistura de metais em baixas concentrações foi capaz de impactar a morfologia hepática e renal de ratos, tanto em regime de exposição aguda quanto subcrônica.
Although mining is considered an activity of great importance for the development of a society, it is associated with several environmental impacts when carried out without planning and without adequate supervision. Brazil exports several products of mineral origin, with iron ore one of the most relevant. In 2015, the Fundão mining tailings dam located in Mariana, Minas Gerais collapsed. This accident caused several socio-environmental damages and contamination along the Rio Doce basin by metals such as Cadmium (Cd), Lead (Pb), Arsenic (As) and Manganese (Mn). There are several studies in the literature that investigated the toxicity exerted by these metals isolated, both in humans and in experimental models. However, there are no studies with mixtures of metals, such as those found in the water of the Rio Doce basin after the aforementioned environmental accident. Thus, studies aimed at evaluating the toxicity of these complex mixtures, especially at environmentally referenced concentrations, are necessary for a better understanding of possible chemical interactions. In this context, the present study used a mixture of metals found in higher concentration in the sludge from the accident, i.e., Mn, As, Pb and Cd, aiming to elucidate their adverse effects on the hepatic and renal morphophysiology of adult male rats after acute (single dose, evaluation after 24h) or subchronic exposure (30 days of treatment), using environmentally relevant concentrations. The results showed that the animals acutely exposed to the mixture of metals did not present comorbidities, however they presented important histopathological alterations in the liver and kidneys, as well as a decrease in the serum levels of Alanine transaminase. On the other hand, animals exposed to the mixture of metals for 30 days (subchronic exposure) showed transient changes in general health parameters, especially gastrointestinal changes. Regarding the histopathological analyses, there was an increase in the occurrence of morphological changes both in the liver and in the kidney, without significant changes in biochemical parameters. Thus, it is concluded that exposure to the mixture of metals at low concentrations was able to impact the hepatic and renal morphology of rats, both in acute and subchronic exposure regimes.
Although mining is considered an activity of great importance for the development of a society, it is associated with several environmental impacts when carried out without planning and without adequate supervision. Brazil exports several products of mineral origin, with iron ore one of the most relevant. In 2015, the Fundão mining tailings dam located in Mariana, Minas Gerais collapsed. This accident caused several socio-environmental damages and contamination along the Rio Doce basin by metals such as Cadmium (Cd), Lead (Pb), Arsenic (As) and Manganese (Mn). There are several studies in the literature that investigated the toxicity exerted by these metals isolated, both in humans and in experimental models. However, there are no studies with mixtures of metals, such as those found in the water of the Rio Doce basin after the aforementioned environmental accident. Thus, studies aimed at evaluating the toxicity of these complex mixtures, especially at environmentally referenced concentrations, are necessary for a better understanding of possible chemical interactions. In this context, the present study used a mixture of metals found in higher concentration in the sludge from the accident, i.e., Mn, As, Pb and Cd, aiming to elucidate their adverse effects on the hepatic and renal morphophysiology of adult male rats after acute (single dose, evaluation after 24h) or subchronic exposure (30 days of treatment), using environmentally relevant concentrations. The results showed that the animals acutely exposed to the mixture of metals did not present comorbidities, however they presented important histopathological alterations in the liver and kidneys, as well as a decrease in the serum levels of Alanine transaminase. On the other hand, animals exposed to the mixture of metals for 30 days (subchronic exposure) showed transient changes in general health parameters, especially gastrointestinal changes. Regarding the histopathological analyses, there was an increase in the occurrence of morphological changes both in the liver and in the kidney, without significant changes in biochemical parameters. Thus, it is concluded that exposure to the mixture of metals at low concentrations was able to impact the hepatic and renal morphology of rats, both in acute and subchronic exposure regimes.
Descrição
Citação
D’ASSUMPÇÃO, Thalita Tofanin Sargiani. Toxicidade hepática e renal exercida por mistura de metais em baixas concentrações: estudo experimental em ratos machos. 2022. 49 f. Dissertação (Mestrado em Bioprodutos e Bioprocessos) - Instituto de Saúde e Sociedade, Universidade Federal de São Paulo, Santos, 2022.