Repeated-dose toxicity attributed to aluminum nanoparticles following 28-day oral administration,particularly on gene expression in mouse brain

Nanotechnology is a rapidly growing industry that has elicited much concern due to the lack of available toxicity data. Aluminum oxide nanoparticles (AlNP) were listed as a high-priority group in the Organization for Economic Co-operation and Development (OECD) Steering Group for Test Guidelines. In this study, AlNP 35 ± 18.8 nm in size were administered daily at doses of 15, 30, or 60 mg k^?1 for 28 days. A significant decrease in white blood cells (WBC), neutrophils, lymphocytes, and monocytes was observed in the group treated with 60 mg kg^?1 of AlNP, accompanied by a significant increase in platelets. The concentration of aluminum (Al) rose significantly in the thymus, lung, and brain of the group treated with 60 mg kg^?1 of AlNP. However, no significant changes in histopathology were observed. The expression for feeding behavior, energy expenditure, and neurodegeneration-related genes were up-regulated more than twofold by 60 mg kg^?1 AlNP. Consequently, data suggest that exposure to AlNP may result in adverse health effects, including but not limited to growth inhibition, immunosuppression, and neurodegeneration.