AIM: To investigate the influence on blood-retina barrier after intense light exposure in rats.

METHODS: The rats were randomly divided into light exposure group and control group. Rats in light exposure group were exposed in white light(10 000lux,12h on-off, continuing 1-14d). Rats in control group were only exposed in natural light. The eyes of the rats in the two groups were removed when the rats in light exposure group acceptted intense light after 1, 3, 7 and 14d. We observed the change of retinal structure using hematoxylin-eosin(HE)staining, and observed the change of retinal ultrastructure using electron microscope. We quantified the change of retinal vascular permeability using laser scanning confocal fluorescence microscope and spectrophotometry after perfusion of Evans-blue, to evaluate the change of blood-retinal barrier.

RESULTS: At 1d after intense light exposure, the retinal ultrastructure of rats changed, such as denaturation of photoreceptor cells and falling of membranous disc outer segment and thinning of the outer nuclear layer thickness, and so on; and the longer the rats exposure to intense light, the more serious change of the retinal ultrastructure were found. At 3d later, photoreceptor cells began apoptosis. At 14d later, the outer nuclear layer became thinner obviously, and the number of cells reduce obviously. At 1d after intense light exposure, EB leaked from the retinal vascular, and at 14d later the leaking of EB was more obvious.

CONCLUSION: The photoreceptor cell of the outer nuclear layer of retina will degenerate and apoptosis, and the outer nuclear layer will be thinner, and the structure and function of blood-retinal barrier will be destroied, if the eyes of rats exposed in intense light.