The Translocation of Nuclaer Factor Kappa B on Corneal Epithelial Cells after Ultraviolet B Irrradiation

ABSTRACT

PURPOSE: To seek the role of nuclear factor kappa B (NF-kB) on the corneal epithelial cell death after ultraviolet (UV) irradiation. METHODS: Human corneal epithelial cells transfected by Simian Virus 40 were used in this study. UVB(312 nm) located at 10cm distance from bottom (0.6 mW/cm2 ) was irradiated for 10, 20, 30, and 40 seconds. To measure the cytotoxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method was used. Translocation of NF-KB was examined by immunocytochemistry with anti NF-K B p65 antibody and Electrophoretic Mobility Shift Assay (EMSA). To confirm the role of NF-KB , sulfasalazine, a specific inhibitor of NF-KB (0.5 mmole), was pretreated for 30 minutes before irradiatrion, and cytotoxicity and translocation of NF-KB was evaluated. RESULTS: UV irradiation resulted in a significant decrease in viability of cultured human corneal epithelial cells, especially after 20 second duration. When HCECs were irradiated with UVB, the translocation of N F -KB was observed in immunocytochemistry. These translocation was peaked 2 hours after UV irradiation in EMSA. In HCECs pretreated with sulfasalazine, either the cellular death or the translocation of NF-KB was blocked. CONCLUSION: UV irradiation can translocate NF-KB on the cultured human corneal epithelial cells. The cellular death after UV irradiation was blocked by sulfasalazine, a potent inhibitor of translocation of NF-KB. These findings suggest that NF-KB plays an important role in cellular death after UV irradiation.