Comparative Assessment of Aluminum Bioaccumulation and Morphological Changes in the Lungs and Brain after a Single Inhalation Exposure to Nanodispersed Aluminum Oxide

Abstract

Accumulation of aluminum was established in the brain and lungs of ICR (CD-1) line mice after a single 4-h inhalation exposure to aerosols of water suspensions of nanodispersed aluminum oxide with particle size 30–40 nm in the actual concentration equal to 0.16 mg/m³ and microdispersed analogue with particle size 3000–6000 nm in the actual concentration equal to 0.15 mg/m³. Aluminum concentration in the lungs was 14.27 times higher under exposure to nano-particles than to micro-sized ones; aluminum concentration in the brain, 1.34 times higher in animals from the experimental group (exposed to nano-particles) against those from the reference one (exposed to micro-particles). Pathological changes in brain tissues of animals from the experimental group were characterized by subarachnoid hemorrhage, which was not detected in the reference group. Pathological changes in lung tissues of animals from the experimental group were characterized by acute hyperemia and small hemorrhagic infarctions, animals from the comparison group had hyperplasia of lymphoid tissue and eosinophilia of infiltrate. Identified changes in brain and lung tissues prove that aluminum oxide nanoparticles are more toxic in comparison with their microdispersed analogue.