Real-ambient PM2.5 induced corneal epithelial barrier disruption through Wnt/β-catenin signaling

Continued daily exposure to fine particulate matter (PM_2.5) is linked to increasing risks of ocular surface diseases. However, further study is needed to understand how real-ambient PM_2.5 disrupts the barrier function of the corneal epithelial layers and its underlying mechanism. In our study, we utilized a real-ambient PM_2.5 exposure system to investigate its effects on the corneal epithelial barrier in C57BL/6Jmice over 4 and 8 weeks. The mean concentration of PM_2.5 in the exposure chambers over 8 weeks was 140.18 μg/m³. Following 4 and 8 weeks of continuous PM_2.5 exposure, we observed disorganized cellular arrangements in the corneal epithelium of mice. Moreover, PM_2.5 exposure led to a significant loss of microvilli on the surface of corneal epithelial cells and noticeable disconnections among epithelial cell layers. Subsequent in vitro analysis revealed that 100 μg/mL PM_2.5 activated the Wnt/β-catenin signaling pathway in corneal epithelium, resulting in decreased expression 1.81 fold and 2.25 fold of E-cadherin and ZO-1, respectively, ultimately impairing the corneal epithelial barrier function. Our findings provide the knowledge base for promoting eye health in the context of atmospheric pollution.