RESUMO
OBJECTIVE: To investigate the toxic effects of nano-sized neodymium oxide( nano-Nd_2O_3) on the central nervous system in mice. METHODS: Specific pathogen free female ICR mice were randomly divided into control group,lowdose group and high-dose group,with 12 rats in each group. The mice in low-dose group and high-dose group were treated with nano-Nd_2O_3 by nasal drip method at 80 and 160 mg/( kg·d) body weight for 30 days,while the mice in the control group were given 0. 9% sodium chloride solution. The water maze experiment and jump platform experiment were used to evaluate learning and memory ability. Hippocampus was examined using Hematoxylin-Eosin( HE) staining and glial fibrillary acidic protein( GFAP) immunohistochemical staining. The level of malondialdehyde( MDA) and the activity of total superoxide dismutase( T-SOD) in brain tissue were detected by microplate reader. RESULTS: The escape latency increased and the step down latency decreased in the low-dose group and high-dose group compared with the control group(P < 0. 05). No obvious pathological changes were observed by HE staining in brain hippocampus. Immunohistochemistry staining showed that the expression of GFAP protein in the hippocampal astrocytes of the low-and high-dose groups was higher than that in the control group,especially in the high-dose group,when compared with the control group. The MDA level increased and the T-SOD activity decreased in the low-and high-dose groups compared with the control group( P <0. 05). CONCLUSION: nano-Nd2 O3 can reduce the learning and memory ability of mice and increased GFAP expression in hippocampal astrocytes. The mechanism may be related to oxidative stress.