Exposure to silver nanoparticles does not affect cognitive outcome or hippocampal neurogenesis in adult mice

Due to the unique antimicrobial and many other broad spectrum biotechnological advantages, silver nanoparticles (Ag-NPs) are widely used in biomedical and general applications. However, the current knowledge about the impact of Ag-NPs on the central nervous system is extremely limited. To assess whether Ag-NPs influence spatial cognition and adult hippocampal neurogenesis, male ICR mice received intraperitoneal administration of Ag-NPs (10, 25, and 50 mg/kg body weight) or vehicle every day for 7 days. At the end of this time period, Morris water maze test was performed for the spatial learning and memory. Subsequently, mice were injected with bromodeoxyuridine and sacrificed 1 day or 28 days after the last injection in order to evaluate cell proliferation, survival and differentiation in the hippocampus. Results showed that compared with the control group, both reference memory and working memory were not impaired in Ag-NPs exposed groups. In addition, no differences were observed in hippocampal progenitor proliferation, new born cell survival or differentiation. These data reveal that exposure to Ag-NPs does not affect spatial cognition or hippocampal neurogenesis in mice.