The toxic effect of air on primary human retinal pigment epithelium cells.

Purpose: To investigate the toxic effect of air on primary human retinal pigment epithelium cells (RPE) over time. Methods: RPE cultures were retrieved from six donor eyes and cultivated at 37 degrees C in 5% CO2 and 95% humidified air. The RPE were divided in six groups with each group containing four samples. Six groups of RPE cultures were set up and four samples were enclosed in each group: group 1 consisted of samples in which RPE were exposed to air for 1 hour. Group 2 consisted of RPE exposed to air for 3 hours, group 3 for 6 hours group 4 for 12 hours group 5 for 24 hours and group 6 for 36 hours respectively. Results: Six hours after exposure, the morphology of the cells was still intact. At 12 hours few cells appeared enlarged. 24 hours after exposure to air the cells started losing their typical morphology and appeared deformed. Viability was higher than 95% in groups 1-3 while for groups 4-6 was 75.5%, 15.5% and 7.3%, respectively. Conclusion: The toxic effect of air for the studied in vitro model of RPE is not significant for the first 6 hours. The morphology of the cells progressively changed after 12 hours of exposure and almost all cells appeared apoptotic at 36 hours.