The effect of Blue-Light exposure in an ocular melanoma animal model

Purpose: Uveal melanoma (UM) cells lines, when exposed to blue light in vitro, show a significant increase in proliferation. In order to see if the same effect would be seen in vivo, we investigated the influence of blue-light exposure in an animal model of UM. Methods: Twenty albino rabbits were injected with 1 million human UM cells (92.1) into the suprachoroidal space of the eye. Animals were immunosuppressed using cyclosporin A throughout the 8 week long experiment. The animals were divided into two groups of 10 animals each. The experimental group was exposed to blue-light, while the control group was protected from blue-light using a yellow-filter. Intraocular tumor growth was evaluated weekly by fundoscopic examination. One animal was sacrificed per week, after the 2nd week, in order to evaluate progression of the disease. The eyes were removed after sacrifice and the proliferation rates of the re-cultured cells obtained from the intraocular tumors were performed using the Sulfordhamine-B assay. The Student's t–test was used to compare results for statistical significance. Results: Re-cultures of UM cells were establish from 4 and 5 rabbits of the experimental and control group respectively. Cells were re-cultured for a very short period of time (1 passage only) in order to maintain any in vivo cellular changes. The exposure of rabbits to blue light led to an increase in proliferation of the cell lines derived from intraocular tumors compared to the control (p=0.001). Conclusions: There is increasing amount of data suggesting that Blue-light, one of the components of visible light, may influence the progression of UM. Our results warrant further studies to relate the importance of Blue-Light filtering lenses for UM patients.