Mitochondrial profile of olfactory bulb neurons in rats following chronic inhalation exposure to lead oxide nanoparticles

Introduction. Lead nanoparticles are highly toxic and cause severe cell damage. When deposited on the olfactory epithelium in the respiratory tract, lead nanoparticles are captured by olfactory receptors and pass through the synapse into the olfactory bulbs. This can lead to the accumulation of reactive oxygen species and lipid peroxidation in mitochondrial membranes, thereby causing changes in their morphology and functioning, and subsequently inducing cell apoptosis.

The aim of the study. To investigate the effect of lead oxide nanoparticles on the mitochondrial profile of the rat olfactory bulbs following chronic inhalation exposure.

Materials and Methods. Adult female albino Wistar rats were divided into four groups of ten animals each. The experimental animals were chronically exposed to PbO NPs at a concentration of 0.215 mg/m³ for four hours a day, five days a week during four and eight months in a nose-only inhalation toxicity test chamber. After exposure cessation, olfactory bulb samples were collected for electron microscopy. The mitochondrial profile of rat brain neurons was assessed by the degree of damage to the inner membrane.

Results. We observed changes in neuronal mitochondria characteristic of physiological aging. Four-month inhalation exposure to PbO nanoparticles did not lead to significant changes in the mitochondrial matrix while a statistical increase in the mitochondrial health index was observed after 8 months.

Limitations. This study does not include quantitative measurements of the mitochondrial population of neurons.

Conclusions. Chronic 8-month exposure to lead nanoparticles significantly alters the ratio of normal to swollen forms of mitochondria, which may indicate to compensatory mechanisms. The observed changes may be attributed to accumulation of PbO NPs and a shift in their distribution in the olfactory structures, thus highlighting the importance of considering the time factor when assessing the neurotoxicity of lead nanoparticles.

Compliance with ethical standards. Ethics approval was provided by the Local Ethics Committee of the Yekaterinburg Medical Research Center for Prophylaxis and Health Protection in Industrial Workers (protocol No. 4 of July 12, 2022).

Contribution:
Shelomentsev I.G. – study conception and design, scientific editing;
Gorshkolepova A.V. – data collection and processing, draft manuscript preparation;
Muravtseva A.A. – data collection and processing, draft manuscript preparation;
Sutunkova M.P. – study conception and design;
Minigalieva I.A. – study conception and design.
All authors are responsible for the integrity of all parts of the manuscript and approval of its final version.

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

Funding. The study had no sponsorship.

Received: April 13, 2026 / Accepted: July 1, 2026 / Published: August 14, 2026

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