Expression of Fas and Fas ligand on Ultraviolet B-irradiated Skin / 대한피부과학회지

ABSTRACT

BACKGROUND: It is well known that ultraviolet-induced cell death is mediated by p53 and Fas in the skin. Elimination of DNA-damaged cells after ultraviolet radiation(UVR) through sunburn cell(apoptotic keratinocyte) formation is thought to be pivotal for the removal of precancerous skin cells. Sunburn cell formation was found to be dependent on Fas ligand(FasL), a pro-apoptotic protein induced by DNA damage. OBJECTIVE: This study was aimed to evaluate the relationship between changes of Fas/FasL expression and sunburn cell formation by ultraviolet B(UVB) irradiation in rat skin. METHOD: Expression of Fas and FasL induced by UVB was evaluated by western blotting and direct immunofluorescence test. In addition, sunburn cells were counted in the epidermal sections from UVB irradiated rat skin. RESULTS: Fas and FasL expression were increased from 3 and 12 hours as time lapsed after UVB irradiation, respectively. UVB irradiation caused sunburn cell formation from 6 hours after irradiation, and then peaked at 24 hours after irradiation. This result revealed FasL expression is closely related to sunburn cell formation in view of time after irradiation. CONCLUSION: FasL-mediated apoptosis is important for skin homeostasis. Further studies on the roles of Fas/FasL in the UVB-irradiated skin should be performed to understand the response of the skin to ultraviolet irradiation.