Cerium oxide nanoparticles exhibit minimal cardiac and cytotoxicity in the freshwater fish Catostomus commersonii

Metal oxide nanomaterials can cause oxidative, cardiorespiratory, and osmoregulatory stress in freshwater fish. In contrast, cerium oxide nanoparticles (nCeO(2)) can have antioxidant effects but their aquatic toxicity has not been fully characterized. Heart rate and heart rate variability were followed in white sucker (Catostomus commersonii) acutely exposed to 1.0 mg L-1 nCeO(2) for 25 h. Malondialdehyde (MDA) was measured to assess oxidative tissue damage, and plasma cortisol, glucose, lactate, and osmolality were assessed as indicators of physiological and osmoregulatory stress. There was no MDA accumulation in gill or heart of fish exposed to nCeO(2) and heart function was unchanged over the 25 h treatment. Plasma cortisol increased 6-fold but there was no change in plasma glucose or lactate. Cellular osmoregulatory toxicity was studied using an isolated red blood cell (RBC) modelln vitro exposure to 1.0 mg L-1 nCeO(2) for 1 h had no effect on cell morphological parameters and did not sensitize RBCs to hemolysis under hypotonic stress. Overall, there were no indications of oxidative, cardiorespiratory, or osmoregulatory stress following acute exposure to nCeO(2). Elevated plasma cortisol levels suggest that nCeO(2) may exert mild toxicity to tissues outside of the cardiorespiratory system. (C) 2015 Elsevier Inc. All rights reserved.