Abstract
Purpose :
To determine if particulate matter (PM)2.5, a major outdoor and indoor air pollutant worldwide, induces reactive oxygen species (ROS) in the cornea and exacerbates bacterial infection.
Methods :
Cell viability was tested using an MTT assay in human and mouse corneal epithelial cells. PM2.5 (100µg/ml for 24 h) effects on ROS generation, proinflammatory molecule production, and inflammasome activation were tested using an ROS assay kit, RT-PCR, immunostaining and Western blot. In vivo, the effects of ocular PM2.5 exposure (400µg/ml, begun at 6 h post infection and continued 2X daily) were tested in infected inbred mice that were either T helper cell (Th)1 (C57BL/6) or Th2 (BALB/c) responders to Pseudomonas aeruginosa (PA) antigens.
Results :
In vitro data revealed PM2.5 decreased cell viability (human and mouse corneal epithelial cells), increased ROS and upregulated proinflammatory and oxidative stress associated molecules significantly. Immunostaining and Western blot analysis confirmed inflammasome activation and integrated density values showed significant ASC dimer and trimer formation. In vivo studies showed that: exposure to PM2.5 caused corneal abnormalities and enhanced keratitis in Th2 responder and resulted in earlier (2 days after infection) corneal perforation in Th1 responder mice after PA infection compared to controls.
Conclusions :
These studies provide evidence that PM2.5 induces ROS mediated oxidative stress in the cornea, upregulates innate immune responses and exacerbates keratitis induced by PA.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.