Toxicity of Biogenic Secondary Organic Aerosol toward Nerve Cells

Secondary organic aerosol (SOA) accounts for a large fraction of fine particulate matter (PM_2.5) in the atmosphere. Epidemiological studies have shown that SOA has adverse effects on human health. However, the current knowledge of the SOA's effect on the nervous system remains poorly understood. To address this issue, PC12 cells were incubated in SOA from α-pinene ozonation. The results showed that concentration-dependent increases in reactive oxygen species (ROS) levels lead to a decrease in cell viability, indicating that SOA could induce apoptosis and oxidative stress in cells. The peroxides present in the SOA are identified as major contributors to the apoptotic effect. Furthermore, the apoptosis mechanism was analyzed by Western blotting, revealing activation of the mitochondria-associated Bax/Bcl-2-Caspase-3-PARP signal pathway. In addition, the qPCR result showed that SOA had altered the expression of inflammatory factors, including IL-6, IL-1β, and TNF-α, in PC12 cells. This study investigates the molecular-level evidence of the toxicological impact of SOA on the nervous system, which further evaluates the effects of SOA on health.