Pulmonary Responses of Manufactured Ultrafine Aluminum Oxide Particles Upon Repeated Exposure by Inhalation in Rats

The aim of this study is to evaluate the pulmonary effects of manufactured ultra fine (10 nm) aluminum oxide particles (UFAOP) upon repeated exposure by inhalation. Rats were exposed with UFAOP in nose-only inhalation chambers at concentrations of 0, 50, 100, and 160 mg/m3 for 6h per day on 5 days. Bronchoalveolar lavage analysis showed pulmonary inflammation and cytotoxicity. Histopathology of lungs showed particle induced cytotoxicity and inflammation characterized by mononuclear inflammatory cell infiltration. Lung burden data showed less percentage of clearance and higher biological half time for UFAOP. Based on our results we conclude that repeated inhalation exposure of UFAOP induced concentration dependant toxicity to lungs of rats at different time points of post exposure.