Evaluation of the effects of cerium oxide nanoparticles on zebrafish embryos

In this study, it was aimed to determine the toxic effects of cerium oxide (CeO2) nanoparticles (NP), doxorubicin (DOX) and DOX-CNP mixtures with different particle sizes (Bulk, 5-25-50 nm) on zebrafish (Danio rerio) embryos. In addition, it was aimed to evaluate whether CNPs have an antioxidative protection in relation to their particle size. Therefore, in this study, it was aimed to evaluate the toxic effect of DOX, a chemotherapeutic agent, in zebrafish embryos and the protection of CNPs against reactive oxygen species that may occur in cells afterward. In order to determine possible effects with the research, the effects were evaluated using the zebrafish embryonal development and malformation test, which is a simple and effective test. Embryonal development, malformations occurring during development, and heart rate were examined. In order to evaluate the possible antioxidative effect in the organism, glutathione S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), catalase (CAT), carboxylesterase (CaE) were evaluated as biochemical markers. The LC50 value of DOX was determined as 74 µM. It was determined that DOX exposure suppressed development in embryos, caused shortening in total body length, prolongation of hatching times, increased heart rate and various malformations. No significant morphometric toxicity was observed in embryos exposed only to the effects of CNPs. This suggests that CNP exposure may have a protective and antagonistic effect, despite the toxicity caused by DOX exposure, and that CNP may reduce DOX-induced toxicity. On the other hand, as a result of the evaluation of biochemical markers, it was evaluated that CeO2 application did not have a sufficient effect in eliminating the toxic effect caused by DOX. Although it is thought that the toxicity of DOX may be partially reduced when CNPs are administered together with DOX, extensive research is needed to better understand the mechanism. Keywords: Nanoparticle, Cerium oxide, Zebrafish, D. rerio, Toksicity, Antioxidative effect