Cannabidiol modulates brain copper homeostasis in wild-type-like but not Alzheimer’s disease transgenic female mice: Implications for neuroprotective therapy

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterised by cognitive decline, synaptic dysfunction, and neuroinflammation. Disrupted metal homeostasis—particularly involving copper (Cu), zinc (Zn), and iron (Fe)—is implicated in AD pathogenesis, where these metals contribute to amyloid-beta (Aβ) aggregation, oxidative stress, and tau pathology. Cannabidiol (CBD), a non-toxic phytocannabinoid, exhibits antioxidant and neuroprotective properties in preclinical AD models, but its influence on brain metal regulation remains poorly defined. Here, we used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify regional metal distributions in sagittal brain sections from 12-month-old wild-type-like (WT) and APP/PS1 transgenic females, either treated chronically with CBD or vehicle. Concentrations of Cu, Zn, and Fe were measured in the whole brain, hippocampus, and cerebellum. CBD treatment significantly elevated whole-brain Cu levels in WT mice, while no such effect was observed in APP/PS1 mice. Although Zn and Fe levels did not differ significantly between groups, effect size analysis and visual trends revealed genotype-dependent shifts in regional Zn and Cu distribution, particularly in the hippocampus. Correlation analysis demonstrated coordinated inter-regional metal regulation in WT and APP/PS1 mice, which was disrupted in APP/PS1 females treated with CBD. Intra-group variance analysis indicated greater Cu variability in CBD-treated WT animals, particularly in the cerebellum, compared to all other experimental groups. This suggests individual differences in CBD response, potentially driven by metabolic, genetic, or neurophysiological factors. These findings demonstrate that CBD modulates Cu homeostasis in a genotype-dependent manner, with potential implications for metal-associated toxicity or therapeutic targeting. The absence of effect in 12-month-old APP/PS1 females highlights the need to account for disease state when evaluating potential cannabinoid-based interventions. This study supports the integration of spatially resolved metallomics into preclinical frameworks and suggests that metrics beyond mean concentration—such as regional ratios, correlation structures, and variability—can provide sensitive indicators of therapeutic impact.