Observation of ultrastructural changes in cultured retinal pigment epithelium following exposure to blue light

Abstract 

· Background: The retina can be damaged by light even when levels of energy are well below the threshold for thermal damage, and the experimental damage of the retinal pigment epithelium (RPE) may be induced more easily by blue light than by longer wavelengths of visible light. The present study demonstrates the ultrastructural damage produced by exposure to blue light in cultured RPE. · Methods: Long-Evans rats were enucleated 8–10 days after birth for primary culture. One week after seeding, the monolayer culture of RPE cells was exposed to a cool blue light (wavelength = 440±10 nm) for 36 h (12 h/day, 3 days) at 2.0 mW/cm². Transmission electron microscopy was used to compare the exposed RPE with the control. The entire experiment was repeated 3 times independently. · Results: The cytoplasm of the exposed RPE exhibited degenerative changes, such as large whorls of membrane, lamellar whorls and whorled inclusions. · Conclusion: The RPE cells can be damaged directly by blue light after excluding the possible influence of phagosomes. This primary culture of RPE can also serve as an in vitro model for the study of light damage to the RPE.