The effect of silver nanoparticles on learning and memory in rodents: "a systematic review"

Abstract

Background Silver nanoparticles (AgNPs) are widely used in medicine owing to their antiseptic activity and inducing cell death. Despite AgNPs' importance in nano-engineering and medical benefits, animal studies have shown silver toxicity can damage multiple organs such as the lungs, liver, kidneys, intestines, and brain. Several investigations revealed the correlation between Ag administration by different methods with impaired cognitive and behavioral abilities. Therefore, this systematic review aimed to conclude on the existing evidence of impairments in learning and memory that were changed in rodents exposed to AgNPs. Methods Main searches were retrieved in Google Scholar, Scopus, Web of Science, and PubMed databases from 1979 to 2022. Eligibility Criteria were applied to select and extract 15 articles among 892. Results Learning and memory abilities of rats and mice in screened studies were evaluated with MWM, NORT, PAL, T-maze, Y-maze, contextual fear conditioning, Radial Arm Maze and Carousel Maze test. Data have shown various sizes from 10 to 100 nm could affect the results of tests among animals exposed to AgNPs compared with control animals. However, in some treatments, results achieved from tests have not demonstrated significant differences between control and treated groups. Conclusion Studies have revealed that treatment with Ag-NPs of different sizes can impair learning and memory skills in rats and mice.

Tests for learning and memory in rodent regulatory studies

“…Chaining can be prevented by closing un-chosen arms on each trial until the rat returns to the center before opening all arms before the rat makes a new choice. The RAM has been used in both pharmacological ( Olton, 1987 ) and neurotoxicity studies ( Tsuji and Crofton, 2012 ) and many studies show treatment effects, e.g., ( Buresova and Bures, 1982 , Gibbs and Johnson, 2008 , Kenney and Gould, 2008 , Zlomuzica et al, 2009 , Conrad, 2010 Levin, 1988 , Safaei et al, 2023 ) but it requires food restriction to maintain equivalent motivation in all rats, typically to 85 % of their free feeding weight. Egocentric L&M : One test that is used for egocentric learning in safety studies is the BWM and to a lesser extent the CWM ( Vorhees, 1987 , Vorhees et al, 1991 ).…”