Studies On Indoor PM_2.5 Toxicity To BEAS-2B Cell And Its Organic Composition

Particulate matter?PM?,an important type of air pollutants,has been classifed as aGroup 1 human carcinogen by the International Agency for Research on Cancer?IARC?.An elevated level of ambient fine particulate matter?PM?with aerodynamic diameter < 2.5?m(PM_2.5)is a major risk factor for increased cardiopulmonary morbidity and mortality.PM_2.5is an“invisible killer”to human health.While PM_2.5 is often reported as a single atmospheric species,it is actually a mixture of organic and inorganic compounds.The organic fraction,termed organic aerosol?OA?,contributes approximately 20-70% of the PM_2.5 mass globally,and OA itself is a complex mixture of thousands of compounds.Previous studies have documented that exposure to PM triggers ROS generation and results in apoptosis.According to the hierarchical oxidative stress hypothesis,the lowest level of oxidative stress is associated with the induction of antioxidant and detoxification enzymes.At higher levels of oxidative stress,this protective response is overtaken by inflammation and cytotoxicity.Whereas programmed cell death could result from mitochondrial perturbation and the release of proapoptotic factors.Here,PM_2.5 samples were collected from the public places of Shenyang,such as hotels,restaurants,supermarkets and shopping malls during November 6,2012 to February26,2013,and analyzed by GC-MS.Cellular apoptosis rate and proliferation rate were analyzed after the stimulus of PM_2.5.According to the hierarchical oxidative stress hypothesis,9 genes were chose to detect their expression using q PCR.The results showed that PM_2.5 can increase cellular apoptosis rate and mortality.The stimulus of the PM_2.5 cause the cells to start the Keap1-Nrf2/ARE signaling pathway,inflammatory signaling pathway and PI3K-Akt signaling pathway.The correlativity was analyzed between the single organic component of PM_2.5 and cytotoxicity by using SPSS software.The results showd that there was a significant correlation between them.Y-shaped microfluidic shear device was designed for simulating micro environmental in vivo.Dynamic PM_2.5 was loaded to stimulate the BEAS-2B cells in the Y-shaped microfluidic shear device,and the release of ROS were detected.The results showed that dynamic PM_2.5 could induce cells to produce a large number of ROS,leading to cell damage.