Toxicity of low doses of ultrafine diesel exhaust particles on bovine brain microvessel endothelial cells

Abstract

Diesel exhaust particles (DEPs) are an important risk factor for various health conditions including neurodegenerative diseases. However, information regarding the toxicity of low doses of ultrafine DEPs in relation to the brain is limited. This study was performed to evaluate the neurotoxicity of low doses of ultrafine DEPs (ng/mL level) using bovine brain microvessel endothelial cells (BMECs) as a model of the blood-brain barrier (BBB). The cells were exposed to various concentrations of DEPs (from 1.28 ng/mL to 20 μg/mL) for 24 h, and cytotoxicity was evaluated by assaying lactate dehydrogenase activity, the generation of reactive oxygen species (ROS) by the dichlorofluorescein diacetate method, total antioxidant capacity (TAC) using bathocuproinedisulfonic acid disodium salt, and cell permeability by measuring the flux of fluorescein. The results showed that low doses of DEPs decreased cell viability and induced oxidative stress by increasing ROS generation and decreasing TAC in a dose-dependent manner. Furthermore, DEPs exposure increased BMECs permeability. This study shows that exposure to low doses of ultrafine DEPs might disrupt the function of BMECs and generate oxidative stress, suggesting that exposure to DEPs even at extremely low doses may compromise the integrity of the BBB and induce adverse effects in the central nervous system.