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Alterações histológicas em brânquias de Oncorhynchus mykiss após exposição crónica a concentrações ambientalmente realistas de nanopartículas de dióxido de cério
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| PPG_22164 | 1.71 MB | Adobe PDF |
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Abstract(s)
Nos dias de hoje, as atividades de investigação, inovação e desenvolvimento em nanopartículas (NPs) metálicas têm levado a grandes avanços tecnológicos. Daqui, resultou uma transferência de tecnologia para os diferentes sectores de atividade humana, permitindo que atualmente as nanopartículas de dióxido de cério (NPs de CeCO2), por exemplo, sejam fortemente utilizadas na indústria para a produção de painéis solares e fotovoltaicos, em bombas aerificadoras para colocar em aquários domésticos, nos aparelhos para detetar fuga de gás e como aditivos de combustível. Contudo, poucos são os estudos existentes que avaliam a toxicidade ambiental das nanopartículas metálicas no compartimento aquático, em particular das NPs de CeCO2. Neste âmbito realizou-se uma exposição crónica (com a duração de 28 dias) da espécie Oncorhynchus mykiss (n.v. truta arco-íris) a três concentrações crescentes de NPs de CeCO2 (0,1 μg/L, 0,01 μg/L e 0,001 μg/L), incluindo um grupo controlo, e aferiu-se a sua toxicidade em termos de danos tecidulares produzidos ao nível das brânquias. Na avaliação histopatológica podemos referir que os indivíduos expostos a NPs de CeCO2 apresentaram alterações muito marcadas nas brânquias, como por exemplo aneurismas, levantamento epitelial, hipertrofia, edema intercelular, hiperplasia, fusão das lamelas secundárias e necrose. A análise semi-quantitativa permitiu ainda demonstrar claramente a existência uma relação dose-efeito observando-se diferenças significativas no índice patológico branquial entre as diversas concentrações testadas e o grupo controlo. Os resultados obtidos indicam que as NPs de CeO2 causam danos marcados no tecido branquial de O. mykiss em concentrações sub-letais, embora ambientalmente relevantes. Este efeito deletério no tecido branquial poderá ser traduzido pela perda de algumas das suas reconhecidas funções fisiológicas com consequências óbvias para os indivíduos.
At present research, innovation and developing activities in the nanoparticles field have led to major technological advances. This resulted in a technological transfer of this know-how for different sectors of human activity. Cerium dioxide nanoparticles (CeCO2 NPs), for example, are widely used in industry for the production of solar and photovoltaic panels, in air pumps for domestic aquariums, in electric devices to detect gas leakage and as fuel additives. However there are few existing studies assessing the environmental toxicity of metallic nanoparticles in the aquatic compartment, particularly CeCO2 NPs. In this context a chronic exposure (lasting 28 days) of the species Oncorhynchus mykiss (rainbow trout) to three increasing concentrations of NPs CeCO2 (0.1 g / L, 0.01 g / L and 0.001 g / L), including a control group, was performed to assess its toxicity in terms of gill’s tissue damage. The histopathological evaluation of individuals exposed to CeCO2 NPs showed very marked changes in the gills, such as aneurysms, epithelial lifting, hypertrophy, intercellular edema, hyperplasia, fusion of secondary lamellae and necrosis. Furthermore the semi-quantitative analysis clearly demonstrated a dose-effect relationship showing a significant increase of the gill’s pathological index of the exposed groups compared with the control group. The hereby results indicate that NPs CeO2 can cause marked damage on gill tissue of O. mykiss exposed to sub-lethal concentrations, but environmentally significant. These deleterious effects on gill’s tissue could result in the loss of some of its recognized physiological functions with obvious consequences for the individuals.
At present research, innovation and developing activities in the nanoparticles field have led to major technological advances. This resulted in a technological transfer of this know-how for different sectors of human activity. Cerium dioxide nanoparticles (CeCO2 NPs), for example, are widely used in industry for the production of solar and photovoltaic panels, in air pumps for domestic aquariums, in electric devices to detect gas leakage and as fuel additives. However there are few existing studies assessing the environmental toxicity of metallic nanoparticles in the aquatic compartment, particularly CeCO2 NPs. In this context a chronic exposure (lasting 28 days) of the species Oncorhynchus mykiss (rainbow trout) to three increasing concentrations of NPs CeCO2 (0.1 g / L, 0.01 g / L and 0.001 g / L), including a control group, was performed to assess its toxicity in terms of gill’s tissue damage. The histopathological evaluation of individuals exposed to CeCO2 NPs showed very marked changes in the gills, such as aneurysms, epithelial lifting, hypertrophy, intercellular edema, hyperplasia, fusion of secondary lamellae and necrosis. Furthermore the semi-quantitative analysis clearly demonstrated a dose-effect relationship showing a significant increase of the gill’s pathological index of the exposed groups compared with the control group. The hereby results indicate that NPs CeO2 can cause marked damage on gill tissue of O. mykiss exposed to sub-lethal concentrations, but environmentally significant. These deleterious effects on gill’s tissue could result in the loss of some of its recognized physiological functions with obvious consequences for the individuals.
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Keywords
Truta arco-íris Exposição Nanopartículas Dano tecidular Rainbow trout Exposure Nanoparticles Tissue damage