In vivo and in vitro ecotoxicity assessment of pharmaceuticals and nanoplastics for early life stages of amphibians

• Autor(a) principal: Morais, Filipa Vital
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/33424
• topic: Ecotoxicity; Xenopus laevis; Pelophylax perezi; Amphibian cell line; Polystyrene nanoplastics.

The technological expansion allowed the development of active substances that promoted an improvement of human life quality and a population increase. However, the increase in the consumption of pharmaceutical substances, in terms of quantity and variety, has promoted its environmental presence, namely in aquatic systems. Considering the bioactive nature of these substances, undesirable effects may be expected in the biota inhabiting ecosystems that receive these chemicals. Among this biota are the amphibians, which constitute a group of organisms that shows a high sensitivity to environmental changes. The present study aimed to assess the individual and combined effects of two pharmaceutical drugs (propranolol and haloperidol), alone and in combined exposures with nanoplastics (50 nm polystyrene particles), to aquatic life stages (embryos and tadpoles) of Xenopus laevis and Pelophylax perezi. Assessed endpoints included mortality, malformations and growth (as length and weight). Furthermore, effects of the selected xenobiotics on two amphibian cell lines (A6, an epithelial line derived from the kidney of an adult male; and XTC-2, a fibroblast-like line derived from a tadpole) were assessed using in vitro assays, by monitoring cell viability, to validate its relevance as a non-animal alternative to assess potential risks to amphibians. Thus, embryos and tadpoles of X. laevis and P. perezi and the two cell lines (A6 and XTC-2) were exposed to pharmaceuticals and nanoplastics, alone or in binary mixtures. Overall, the results showed that X. laevis tadpoles were more sensitive than the respective embryos to the tested pharmaceuticals. When comparing the two species, the tadpoles of X. laevis tended to be slightly more sensitive than those of P. perezi. Single exposure to 50 nm polystyrene nanoplastics caused no effects on the selected endpoints (lethal or non-lethal), despite their ingestion by the tadpoles. The comparison of the two selected approaches, in vivo versus in vitro, revealed that the latter were less sensitive to the pharmaceuticals. In vitro, individual exposure to polystyrene nanoplastics caused no significant effects on the cell viability of the tested cell lines. However, in mixtures, significant effect of its presence was observed for A6 cell lines, which revealed to be more sensitive than XTC-2 cell line. In vivo, for the pharmaceuticals drugs, the mixture caused a higher mortality at a lower concentration of nanoplastics, demonstrating the relevance of testing environmentally relevant concentrations of xenobiotics and the need to fully characterize nanoplastics in the test media (e.g., concentration, size, ability to form aggregates).