Avaliação histomorfométrica e biomarcadores de estresse oxidativo em órgãos reprodutores de ratos machos expostos a doses supra fisiológicas de manganês
Data
2017
Autores
Santiago, Marcella da Silva Araujo 
Orientadores
Perobelli, Juliana Elaine
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
O manganês (Mn) é um dos elementos químicos mais encontrados na Terra, ocorrendo principalmente na forma de pirolusita (MnO2). É utilizado na indústria química, na fabricação de permanganato de potássio e hidroquinona, de fertilizantes e ração de animais, tintas, resistências elétricas, fogos de artifício, dentre outros. Sua conversão em sais solúveis contribui para a contaminação de rios e mares.É um metal considerado essencial para a fisiologia dos mamíferos, porém tóxico quando em doses altas, sendo as principais fontes de intoxicação a mineração e a indústria siderúrgica. Nesse contexto, o presente estudo avaliou os riscos da exposição a níveis suprafisiológicos de manganês sobre parâmetros reprodutivos e biomarcadores de estresse oxidativo de ratos machos adultos. Ratos machos adultos da linhagem Wistar (n=24) foram distibuídos em três grupos (n=8/grupo): C (controle, recebeu apenas o veículo, solução salina a 0,9%); Mn1 (recebeu cloreto de manganês, MnCl2, na dose de 5 mg/Kg de peso corpóreo); Mn2 (recebeu cloreto de manganês, MnCl2, na dose de 15 mg/Kg de peso corpóreo). Os tratamentos foram aplicados diariamente por via intraperitonial, do dia pós-natal (DPN) 90 ao 120, periodo no qual os animais foram avaliados quanto à evolução do peso corpóreo. No DPN 120 foram eutanasiados para avaliação dos parâmetros de interesse.Houve redução do peso corpóreo dos animais do grupo Mn2, além de redução no peso absoluto do epidídimo e próstata dos animais dos grupos Mn2 e Mn1, quando comparados ao C. Ademais, o tratamento induziu aumento na porcentagem de túbulos seminíferos anormais nos animais Mn1 e Mn2, com ocorrência vacúolos no epitélio, células acidófilas e focos de degeneração. No ducto epididimário, observamos redução de espermatozoides e presença de células na luz. Quando à avaliação de estresse oxidativo, houve um aumento na atividade da Glutationa Peroxidase no epidídimo do grupo Mn2 em relação ao C. Os resultados obtidos mostram que, nessas condições experimentais, o manganês exerceu acentuada toxicidade reprodutiva, comprometendo a histoarquitetura das gônadas dos animais estudados, indicando prejuízo grave à saúde reprodutiva dos ratos, provavelmente devido a desregulação do status androgênico dos animais expostos ao Mn.
Manganese (Mn) is one of the most commonly found chemical elements on Earth, occurring mainly in the form of pyrolusite (MnO2). It is used in the chemical industry, in the manufacture of potassium permanganate and hydroquinone, fertilizers and animal feed, paints, electric resistances, fireworks, among others. Its conversion into soluble salts contributes to the contamination of rivers and seas. It is a metal considered essential for physiology of mammals, but toxic when in high doses, being mining and steel industry the main sources of intoxication. In this context, the present study evaluated the risks of exposure to supraphysiological levels of manganese on reproductive parameters and biomarkers of oxidative stress in adult male rats. Adult male Wistar rats (n = 24) were distributed into three groups (n = 8 / group): C (control, received only vehicle, 0.9% saline); Mn1 (received manganese chloride, MnCl2, at 5 mg/kg body weight); Mn2 (received manganese chloride, MnCl2, at 15 mg/kg body weight). The treatments were applied daily intraperitoneally, from the postnatal day (PND) 90 to 120. During treatment period the animals were evaluated for the evolution of body weight.On PND 120 they were euthanized to evaluate the parameters of interest. There was a reduction in body weight of Mn2 group, as well as a reduction in the absolute weight of the epididymis and prostate of the animals of Mn2 and Mn1 groups when compared to the C. In addition, treatment induced an increase in the percentage of abnormal seminiferous tubules in the Mn1 and Mn2, with occurrence of vacuoles in the epithelium, acidophilic cells and foci of degeneration. In the epididymal duct, we observed reduction of spermatozoa and presence of cells in the lumen. Regarding the oxidative stress analysis, there was an increase in Gluthatione Peroxidase activity in the epididymis of the Mn2 group when compared to C. The results show that, under these experimental conditions, manganese exerted a high reproductive toxicity, compromising the histoarchitecture of the rat gonads, indicating a serious injury to the reproductive health of the animals, probably due to disruption of androgenic status of the animals exposed to Mn.
Manganese (Mn) is one of the most commonly found chemical elements on Earth, occurring mainly in the form of pyrolusite (MnO2). It is used in the chemical industry, in the manufacture of potassium permanganate and hydroquinone, fertilizers and animal feed, paints, electric resistances, fireworks, among others. Its conversion into soluble salts contributes to the contamination of rivers and seas. It is a metal considered essential for physiology of mammals, but toxic when in high doses, being mining and steel industry the main sources of intoxication. In this context, the present study evaluated the risks of exposure to supraphysiological levels of manganese on reproductive parameters and biomarkers of oxidative stress in adult male rats. Adult male Wistar rats (n = 24) were distributed into three groups (n = 8 / group): C (control, received only vehicle, 0.9% saline); Mn1 (received manganese chloride, MnCl2, at 5 mg/kg body weight); Mn2 (received manganese chloride, MnCl2, at 15 mg/kg body weight). The treatments were applied daily intraperitoneally, from the postnatal day (PND) 90 to 120. During treatment period the animals were evaluated for the evolution of body weight.On PND 120 they were euthanized to evaluate the parameters of interest. There was a reduction in body weight of Mn2 group, as well as a reduction in the absolute weight of the epididymis and prostate of the animals of Mn2 and Mn1 groups when compared to the C. In addition, treatment induced an increase in the percentage of abnormal seminiferous tubules in the Mn1 and Mn2, with occurrence of vacuoles in the epithelium, acidophilic cells and foci of degeneration. In the epididymal duct, we observed reduction of spermatozoa and presence of cells in the lumen. Regarding the oxidative stress analysis, there was an increase in Gluthatione Peroxidase activity in the epididymis of the Mn2 group when compared to C. The results show that, under these experimental conditions, manganese exerted a high reproductive toxicity, compromising the histoarchitecture of the rat gonads, indicating a serious injury to the reproductive health of the animals, probably due to disruption of androgenic status of the animals exposed to Mn.
Descrição
Citação
SANTIAGO, Marcella da Silva Araujo. Avaliação histomorfométrica e biomarcadores de estresse oxidativo em órgãos reprodutores de ratos machos expostos a doses supra fisiológicas de manganês. 2017. 37 f. Trabalho de conclusão de curso (Graduação em Bacharelado Interdisciplinar em Ciência e Tecnologia do Mar) - Universidade Federal de São Paulo, Instituto do Mar, Santos, 2017.