Peculiarities of bioaccumulation and toxic effects produced by copper oxide (II) nanoparticles on the respiratory organs under inhalation exposure as opposed to their micro-sized chemical analogue: assessment for prevention purposes

At present, it is quite relevant to get better insight into parameters and peculiarities of deleterious effects produced by copper oxide nanoparticles (CuO NPs) on the respiratory organs under inhalation exposure. This will help develop more effective prevention measures. The aim of this study was to assess peculiarities of bioaccumulation and toxic effects produced by CuO NPs on the respiratory organs as opposed to their micro-sized analogue in experimental modeling of inhalation exposure for prevention purposes. We established physical properties of the tested materials. Experimental studies were accomplished on Wistar rats. The experimental animals underwent a single 4-hour inhalation exposure to a concentration of ~4 mg/m3; a subchronic inhalation exposure to a concentration of 1.2-1.4 mg/m3; a single intratracheal exposure to a dose of 0.005 grams per one rat. We examined peculiarities of NPs bioaccumulation, their influence on the cellular population of the bronchoalveolar lavage fluid (BALF), development of pathomorphological disorders in tissues, and the lung mass in comparison with the micro-sized analogue. CuO NPs, as opposed to their micro-sized analogue, are smaller in size, have smaller hydrodynamic diameters, greater specific surface area and greater total pore volume; these properties determine their greater permeability. Bioaccumulation in the lungs, which was identified for NPs and MPs, is comparable under a single inhalation exposure. Under chronic exposure, NPs tend to bioaccumulate more intensively. A single intratracheal exposure induces more apparent changes in the BALF cellular population. Exposure to NPs causes emphysema, edema, and erythrocyte exudation in the lungs whereas these effects are not identified under exposure to MPs. Therefore, CuO NPs tend to accumulate more intensively and have more deleterious toxic effects on the respiratory organs (the lungs) than their micro-sized chemical analogue under a single intratracheal exposure (0.005 grams per one rat) and subchronic inhalation exposure (1.2 mg/m3). The study results should be considered when developing activities aimed at preventing negative health outcomes in the respiratory organs under inhalation exposure to the analyzed nanomaterial.