Neurotoxicity of PbO nanoparticles following subchronic inhalation exposure of laboratory animals studied at the level of gene expression and metabolome

Introduction. The study of toxicity of lead oxide nanoparticles (PbO NPs) is relevant owing to their ubiquity in the environment and human health impact with the focus on their neurotoxic effects. Apoptosis induced by irreversible DNA damage is one of the possible mechanisms of neurotoxicity. To confirm this hypothesis, studies of ATM and MDM2 gene expression and metabolomic analysis were conducted.

The purpose was to establish neurotoxicity of inhalation exposure of laboratory animals to PbO NPs using gene expression analysis and metabolomics.

Materials and methods. The subchronic experiment with inhalation exposure to PbO NPs at the concentration of 1.55 ± 0.06 mg/m³ was conducted on twenty female albino rats equally divided into exposure and control groups for 5 days a week during 4 weeks. The mRNA level of the ATM and MDM2 genes in olfactory bulbs in the rats was determined by quantitative real-time PCR. Semi-quantitative metabolomic analysis of animal brain tissues was performed using liquid chromatography-mass spectrometry.

Results. ATM gene expression in the olfactory bulb was statistically higher in the exposed animals compared to the controls (p < 0.05). Metabolome analysis revealed changes in the metabolism of lysophosphatidylethanolamines, lysophosphatidylcholines, acylcarnitines, omega-3 polyunsaturated fatty acids, fatty acid amide, phosphorylcholine, inosine, and hypoxanthine in the exposed rodents. For the combination of metabolites detected, a ROC curve with an AUC value of 0.903 was constructed.

Limitations. The study was conducted using female Wistar rats with no potential sex differences considered.

Conclusion. Taken together, the obtained gene expression and metabolomics data indicate that inhalation exposure to PbO NPs at the concentration of 1,55 ± 0,06 mg/m³ induces ATM-mediated p53-induced apoptosis in the animal brain.

Compliance with ethical standards. The local Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers concluded that the animals were kept, fed, cared for, and sacrificed in accordance with generally accepted requirements, taking into account the ARRIVE guidelines. Ethics approval was provided by the Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (protocol No. 5 of October 16, 2023).

Contribution:
Kikot A.M. — data processing, statistical analysis, draft manuscript preparation, editing;
Unesikhina M.S. — data collection and processing, statistical analysis, draft manuscript preparation, editing;
Shaikhova D.R. — data processing, editing;
Bereza I.A. — data collection and processing, editing;
Nikogosyan K.M. — data collection, editing;
Minigalieva I.A. — study conception and design, editing;
Sutunkova M.P. — study conception and design.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Received: March 28, 2025 / Accepted: June 26, 2025 / Published: July 31, 2025

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