Translocation of Nuclear Factor-kappaB on Corneal Epithelial Cells Induced by Ultraviolet B Irradiation

Purpose: This study was performed to elucidate the role of nuclear factor-kappaB (NF-kappaB) in the death of corneal epithelial cells after ultraviolet (UV) irradiation.

Methods: Simian virus 40-transfected human corneal epithelial cells (T-HCECs) were used in this study. Cell cultures were irradiated with a UVB (312 nm) source located 10 cm from the bottom of the slides for 10, 20, 30, or 40 s. Cytotoxicity was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Translocation of NF-kappaB was examined by immunocytochemistry using anti-NF-kappaB p65 antibody and electrophoretic mobility shift assay (EMSA). Sulfasalazine and SN-50, specific NF-kappaB inhibitors, were used to confirm the role of NF-kappaB by pretreating samples for 30 min before UV irradiation, after which cytotoxicity and NF-kappaB translocation were evaluated.

Results: When T-HCECs were irradiated with UVB, translocation of NF-kappaB was observed with immunocytochemistry. These translocations peaked 2 h after UV irradiation during EMSA. When pretreated with sulfasalazine or SN-50, the translocation of NF-kappaB was blocked. Cellular death after UV irradiation was also markedly blocked by sulfasalazine.

Conclusion: These findings suggest that NF-kappaB plays an important role in cellular death after UV irradiation.