Effects of ambient particulate matter on a reconstructed human corneal epithelium model

Ryota Ko,Masahiko Hayashi,Chiharu Nishita-Hara,Eiichi Uchio,Hiroaki Ozaki,Tomoaki Okuda,Miho Tanaka

doi:10.1038/s41598-021-82971-1

Abstract

We 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.

Highlights

We evaluated the effects of ambient particulate matter (PM) on the corneal epithelium using a reconstructed human corneal epithelium (HCE) model
The findings of this study revealed that only a high-dose of PM>2.4 and urban aerosols (UA) significantly decreased cell viability in a reconstructed HCE model, and these particles did not induce the production of proinflammatory cytokines in this tissue
These findings indicate that the most harmful particles to reconstructed HCE tissue may be UA and PM>2.4, followed by P M0.3–2.4, among the particulate matters used in our experiments

Summary

Introduction

We evaluated the effects of ambient particulate matter (PM) on the corneal epithelium using a reconstructed human corneal epithelium (HCE) model. 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. Previous studies have shown the relationship of the ocular surface with DEP using human corneal or conjunctival conventional two-dimensional cell c ultures[12,13]. Cao et al demonstrated that reconstructed human corneal epithelial (HCE) tissue cultures can be used to study the eye-irritating and inflammatory potential of lipopolysaccharides and house d ust[14]. This kind of model closely resembles native corneal epithelium[16].

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Conclusion