Quercetin mitigates aluminum nanoparticle-induced neurotoxicity: a stereological and molecular study on memory, hippocampal integrity, and MAPK signaling.

Emerging evidence suggests a strong association between aluminum (Al) exposure and the development of Alzheimer's disease (AD). Due to their nanoscale size and increased surface area, Al nanoparticles (ALNP) exhibit greater neurotoxicity than bulk Al, raising concerns about their role in neurodegenerative disorders. While quercetin has been recognized for its neuroprotective effects, its ability to counteract ALNP-induced hippocampal neurodegeneration and dysregulated MAPK signaling remains largely unexplored. This study investigated the potential of quercetin to ameliorate ALNP-induced memory deficits, alterations in hippocampal stereological parameters, and disruptions in caspase-3 and MAPK signaling in male Swiss mice. Mice (SWR/J, aged 8-10 weeks) received ALNP (10 mg/kg, intraperitoneally for 10 days) with or without quercetin at doses of 1, 10, or 100 mg/kg (orally). Memory performance was assessed using the elevated plus maze (EPM), novel object recognition (NOR), and Y-maze tasks, followed by stereological and western blot analyses of the hippocampus. Our findings revealed that quercetin (100 mg/kg) significantly preserved hippocampal volume and neuronal integrity in the dentate gyrus (DG) and Cornu Ammonis 1 (CA1)-key regions involved in memory processing and output signaling. Additionally, quercetin modulated MAPK signaling by enhancing ERK phosphorylation while suppressing ALNP-induced activation of p38 and cleaved caspase-3, suggesting a role in reducing neuroinflammation and apoptosis. This is the first study to demonstrate that quercetin can counteract the neurotoxic effects of ALNP, highlighting its potential as a therapeutic strategy against nanoparticle-induced neurodegeneration in an Alzheimer's-like model. See also the graphical abstract.(Fig. 1).