The evaluation of subacute toxicity and endocrine disrupting effects of some nanoparticles by amphibian metamorphosis test

Today, the number of technologies that use nanomaterials and are predicted to be used is increasing rapidly. To evaluate the possible negative effects of these substances, it has become necessary to evaluate the toxic effects of the substances rapidly and simultaneously in parallel with technological use and production. In this study, toxic and endocrine-disrupting effects were evaluated in metamorphotic frog tadpoles exposed to sublethal concentrations (0.001-1 mg/L) of Fe2O3, ZnO CeO2 nanoparticles (NP). In the study, developmental and biochemical marker levels were determined in 51st stage Xenopus laevis tadpoles exposed to NPs for 21 days as predicted in the Amphibian Metamorphosis Test. Post-exposure lethality and developmental stages, body, nose-vent, and hind limb lengths were measured in the indicated organisms. In addition, the activities of glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT) carboxylesterase, acetylcholinesterase enzymes, and malondialdehyde (MDA) and thyroid hormone levels were determined in tadpoles. In tadpoles exposed to the lowest Fe2O3 NP concentration for 21 days, retardation in the growth stage and increase in wet body weight was determined. In 7 days of Fe2O3 exposure, GST inhibition and MDA level were increased. In tadpoles exposed to ZnO NPs, a concentration of 1 mg/L caused growth retardation and induction of GST, GR, and CAT. While none of the CeO2 NP concentrations tested were lethal, the 0.001 and 1 mg/L CeO2 NP concentrations caused an increase in hind limb length and GR inhibition in tadpoles, respectively. The induction of the indicated enzyme activities is thought to be an adaptation of organisms to cope with stress from exposure to an unsafe environment. Enzyme inhibition may be due to interaction with NPs or the reactive oxygen species they cause. In the light of the data obtained, it can be concluded that long-term exposure to low concentrations of NPs may cause toxic and endocrine-disrupting effects in tadpoles.