Abstract
Purpose: :
To evaluate the in vitro toxicity of ultraviolet (UV) light on human retinal pigment epithelial (ARPE-19), rat retinal neurosensory (R28), and human lens epithelial (HLE) cells.
Methods: :
ARPE-19 (ATCC, Manassas, VA), R28 (courtesy of GM Seigel), and HLE (courtesy of UP Andley) cells were treated with different intensities of UV light (5000, 10000, 40000, 900000 µjoule/cm2) using the UV Stratalinker (Stratagene, La Jolla, CA). Cell viability was measured using the trypan blue dye exclusion assay at 24 hours.
Results: :
All intensities of tested UV light (5000, 10000, 40000, 900000 µjoule/cm2) were found to be safe on the ARPE-19 cells. The mean cell viability of ARPE-19 cells after exposure to 5000, 10000, 40000, 900000 µjoule/cm2 of UV light was 94.3%±1.6 (p>0.05), 95.3%±4.1 (p>0.05), 93.3%±2.7 (p>0.05) and 91.7%±0.7 (p>0.05) respectively compared to untreated ARPE-19 control cells (94.2%±2.9). The mean cell viability of R28 cells after exposure to 5000, 10000, 40000, 900000 µjoule/cm2 of UV light was 72.7%±2.1 (p<0.001), 72.2%±2.9 (p<0.001), 60.6%±0.7 (p<0.001) and 22.2%± 3.0 (p<0.001) respectively compared to untreated R28 controls (87.3%± 2.7). The mean cell viability of HLE cells after exposure to 5000, 10000, 40000, 900000 µjoule/cm2 of UV light was 74.6%±2.0 (p<0.001), 71.6%±2.1 (p<0.001), 14.8%±2.0 (p<0.001) and 2.4%±0.9 (p<0.001) respectively compared to untreated HLE control cells (90.2%±1.5).
Conclusions: :
In this study, UV light was non-toxic to ARPE-19 cells. Toxicity was observed in both R28 and HLE cells at all the intensities tested. However, HLE cells were found to be more sensitive to UV light than were R28 cells, with more profound loss of cell viability. These findings correlate with the clinical observation that UV light is cataractogenic but less toxic to the retina.
Keywords: radiation damage: light/UV • retina • retinal culture