Abstract: Objective: To investigate the effects of cerium oxide (CeO₂) nanoparticles on the viabilities of nerve cells PC12 and SH-SY5Y. Methods: CeO₂ nanoparticles were synthesized, structures were characterized and properties were evaluated. PC12 cells and SH-SY5Y cells were treated with CeO₂ nanoparticles at different concentrations (1, 2.5, 5, 10, 25, 50, 75, 100, 150 μg/ml) for 24 h and the cell viability was measured by MTT assay. Then PC12 cells and SH-SY5Y cells were co-treated with CeO₂ and active oxygen scavenger NAC and the cells were stained with DCFH-DA probe for ROS. The number of cells and the fluorescence intensity were observed under a fluorescent inverted microscope. Differences were assessed by one-way ANOVA.Results: After treatment with CeO₂ nanoparticles, the viabilities of both PC12 cells (P＜0.01) and SH-SY5Y cells (P＜0.01) were decreased comparing with the control group. After staining with DCFH-DA probe, the fluorescence intensity of the nerve cells was enhanced depending on the concentration of CeO₂ nanoparticles suggesting that CeO₂ induced the generation of reactive oxygen species (ROS). The fluorescence intensity of PC12 cells was decreased after CeO₂ nanoparticles (100 μg/ml) co-treatment with active oxygen scavenger NAC. Compared with CeO₂ nanoparticles alone at 25 μg/ml (P＜0.01), 50 μg/ml (P＜0.01), 75 μg/ml (P＜0.01), 100 μg/ml (P＜0.01), the cell viability was significantly increased after co-treatment with NAC.Conclusion: CeO₂ nanoparticles has a negative effect on the viabilities of nerve cells PC12 and SH-SY5Y, and the effect might be depend on ROS.

Key words: CeO₂ nanoparticles, reactive oxygen species, neural cells, cell viability, Alzheimer’s disease