A novel system for air-liquid interface exposure to PM2.5 and application to skin 3D culture model

<p>PM2.5 refers to atmospheric particulate matter (PM) that have a diameter of less than 2.5 micrometer. Skin is an important target of PM2.5 as well as respiratory system considering that skin is large organ of the human body and always exposed to PM2.5 outdoors. Most of studies on PM2.5 exposure to skin were conducted by the method that PM2.5-diluted suspension were exposed to keratinocytes or other cells inside skin. However, skin is exposed to PM2.5 in the air, a system of air-liquid interface exposure can be fundamental to investigate the effects of PM2.5 on skin. The aim of this study is to develop a novel air-liquid interface exposure system using skin 3D culture model. </p><p>We used LabCyte EPI-MODEL model as human 3D skin model. The model was incubated in the chamber box under 37℃ and 5％ CO2 condition. PM2.5 suspended solution was atomized with an ultrasonic nebulizer for 1 hr continuously from the surface side of stratum corneum. PM concentration in the chamber was measured by a particle counter equipped with a diffusion dryer to be kept at the concentration of 10 and 100 μg/m3 in the chamber. Thiobarbituric acid reactive substances, an index of lipid peroxidation, was elevated by PM2.5 exposure. Protein levels of inflammatory mediators also were upregulated by PM2.5. Interestingly, these increases under air-liquid interface exposure were significantly potentiated compared with liquid exposure of PM2.5. Taken together, our air-liquid interface exposure system can reproduce actual situation of PM2.5 exposure and be valuable to evaluate the effects of PM2.5 on skin.</p>