Studying and Assessing the Toxicity of Calcium Oxide Nanoparticles under One-Time Inhalation Exposure

Abstract

Under a single 4 hour inhalation exposure to aerosol containing an aqueous suspension of calcium oxide nanoparticles (CaO) in an actual concentration of 6.68 mg/m³, the accumulation of calcium increased in the lungs (by 1.52 times), in the brain (by 1.55 times) and in the liver (by 1.25 times) relative to the control, while exposure to a microdispersed analog in a concentration of 6.37 mg/m³ resulted in an increase in the indicator only in the brain (by 1.27 times). At the same time, the calcium concentration in the brain of animals in the experimental group is higher than in the comparison group (by 1.22 times). After exposure to CaO nano- and microparticles a subarachnoid hemorrhage in the brain tissues was found. The development of pathomorphological changes in the form of lymphoid tissue hyperplasia, eosinophilia, acute arterial plethora, and hemorrhagic lung infarcts, as well as the hydropic and hyaline-drop dystrophy of parenchymal liver tissue was observed only after exposure to CaO nanoparticles. The identified features of the bioaccumulation and pathomorphological changes under inhalation exposure to CaO nanoparticles demonstrate that the studied nanomaterial has a higher level of toxicity in comparison to its microdispersed analog.