Determination of LC50 and sub-chronic neurotoxicity of diesel exhaust nanoparticles

Air pollution is a major problem faced globally and is seen associated with central nervous system (CNS) disorders like neuropathology and neuro-inflammation. Here, we investigated the CNS disorders as a result of sub-chronic exposure (90 days) to diesel exhaust nanoparticles (DENPs) and explored the minimal levels of DENPs needed to exhibit the early mediators of neuro-inflammation and neuropathology. Male and female wistar rats (6 rats per group) were exposed to DENPs (1/5th, 1/10th and 1/15th LC50) by inhalation for 4h per day, 5 days per week over 90 days and neurotoxicity end-points were analyzed. DENP exposure caused elevation in levels of pro-inflammatory cytokines, amyloid beta 42 (Aβ 42), reactive oxygen species (ROS), hydrogen peroxide (H2O2), nitrate (NO3(-)), nitrite (NO2(-)) and apurinic/apyrimidinic sites (AP) at varying degrees at different sections of rat brain. Hence, exposure to DENPs resulted in dose-dependent toxicity and was closely correlated to increased inflammation, DNA damage and oxidative stress.