Study on the mechanism of penetration of particles of air pollution into the brain through the nasal cavity and the potential neurological health risks.

The presence of nanopollutants in the atmosphere poses significant risks to human health. However, research on their adverse effects on the central nervous system (CNS) remains limited. To address this gap, we constructed an in vitro model utilizing mesoporous silica nanoparticles (MSNs) to simulate airborne solid particulates and menthol/curcumol to represent adsorbed liquid microparticles. This model was employed to investigate the impact of nanopollutants on the CNS, focusing on their entry pathways into the CNS and the mechanisms underlying their cellular transport and uptake. The results showed that airborne MSNs could enter the CNS through direct and indirect pathways. Furthermore, co-exposure to liquid microparticles (menthol and curcumol) enhanced the entry of MSNs into the CNS. It was shown that MSNs mixed with curcumol and menthol disrupted certain cellular tight protein components and cell membrane surface integrity. Curcumol and menthol adsorbed onto MSNs also reduced cellular stiffness. Lysosomal co-localization analysis revealed minimal association of intracellular MSNs with lysosomes, suggesting limited biodegradation of these solid and liquid microparticles by lysosomal enzymes following cellular internalization.