AbstractWe evaluated the effects of ambient particulate matter (PM) on the corneal epithelium using a reconstructed human corneal epithelium (HCE) model. We collected two PM size fractions [aerodynamic diameter smaller than 2.4 µm: PM0.3–2.4 and larger than 2.4 µm: PM>2.4] and exposed these tissues to PM concentrations of 1, 10, and 100 µg/mL for 24 h. After exposure, cell viability and interleukin (IL) IL-6 and IL-8 levels were determined, and haematoxylin and eosin and immunofluorescence staining of the zonula occludens-1 (ZO-1) were performed on tissue sections. In addition, the effects of a certified reference material of urban aerosols (UA; 100 µg/mL) were also examined as a reference. The viability of cells exposed to 100 μg/mL UA and PM>2.4 decreased to 76.2% ± 7.4 and 75.4% ± 16.1, respectively, whereas PM0.3–2.4 exposure had a limited effect on cell viability. These particles did not increase IL-6 and IL-8 levels significantly even though cell viability was decreased in 100 μg/mL UA and PM>2.4. ZO-1 expression was reduced in a dose-dependent manner in all groups. Reconstructed HCE could be used as an in vitro model to study the effects of environmental PM exposure on ocular surface cell viability and inflammation.
Expression and Regulation of Cornified Envelope Proteins in Human Corneal Epithelium
