Validation of PM model particle through physicochemical evaluation and atherosclerotic plaque formation in ApoE mice.

PM particles are regarded as prominent risk factors that contribute to the development of atherosclerosis. However, the composition of PM is rather complicated. This study aimed to provide a model particle that simulates the behavior of actual PM, for subsequent use in exploring mechanisms and major complications arising from PM. To establish model particles of PM, a series of monodisperse SiO microspheres with different average grain diameters were mixed according to the size distribution of actual PM. The organic carbon (OC) was removed from PM and coated onto the SiO model particle, to formulate simulant PM. Results showed that the size distribution of the model particle was highly approximate to that of the PM core. The polycyclic aromatic hydrocarbon (PAHs) composition profile of the simulated PM were approximate to PM, and loading efficiency was approximately 80%-120%. Furthermore, compared to the control, SiO-only model particle had negligible cytotoxicity on cell viability and oxidative stress of HUVECs, and marginal effect on the lipid metabolism and atherosclerotic plaque formation in ApoE mice. In contrast, simulated PM exhibited similar cytotoxic and detrimental effects on lipid metabolism and atherosclerotic plaque formation with actual PM. Traffic-related PM had negative effects on endothelial function and led to the formation of atherosclerosis via oxidative stress. The simulated PM simulated the outcomes of actual PM exposure. Here, we show that SiO particle model cores coated with OC could significantly assist in the evaluation of the effects of specific organic compositions bound on PM, specifically in the context of environmental health and safety.