Toxicological effects of urban particulate matter on corneal and conjunctival epithelial cells
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Exposure to urban particulate matter (UPM) is a high-risk factor for various ocular surface diseases, including dry eye syndrome. However, the effects of UPM on corneal and conjunctival epithelium damage have not been fully elucidated. In this study, we investigated the toxicological effects of UPM exposure at high concentrations by using in vitro cultures. The cell viability, mucin expression, and the secreted inflammatory mediators of corneal and conjunctival epithelial cells was observed at 24 h after exposure to UPM. The progression of cell cycle was also examined by flow cytometry at 24 h after exposure to UPM. UPM reduced cell viability in a dose-dependent manner and increased cell population in S and G2 phase. The expression of mucin-1 was attenuated by UPM exposure, but that of mucin-4 was not. UPM increased interleukin (IL)-6 release and decreased IL-8 release. The intensity of 2′,7′-dichlorofluorescein diacetate (DCF-DA) was highest at 4 h of UPM exposure. In conclusion, these results suggest that UPM causes the disruption of corneal and conjunctival epithelium by decreasing cell viability, altering cell cycle, disrupting mucin, and regulating inflammatory mediators.
KeywordsCell cycle Cell death Corneal/conjunctival epithelial cells Mucin Urban particulate mater
Cell Counting Kit-8
Dry eye syndrome
Diesel exhaust particles
Enzyme-linked immunosorbent assay
Nitro-substituted polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons
Reactive oxygen species
Urban particulate matter
World Health Organization
This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry (IPET) through High Value-added Food Technology Development Program, funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) (#317033-03). This work was also supported by Korea Institute of Oriental Medicine (Project No. KSN1812080) and NST (National Research Council of Science & Technology)-KIOM (Korea Institute of Oriental Medicine) Postdoctoral Research Fellowship for Young Scientists.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
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