Abstract: Objective To investigate the function of p53 and p21 in epidermal keratinocytes following UVB irradiation.Methods Using immunohistoehemical staining, the appearance of p53 protein and p21 was detected in the epidermis of rat after exposure to UVB in'adiation.Results The positive reactivity to p53 protein was found at 4h rollowing UVB irradiation, peaked at 8h and returned to undeteetable level at 72h. The appearance of p21 protein was also observed at 4h, but disappeared a little later, and eouht still be detected at 72h.Conclusion UVB caused a rise in wild-type p53 protein levels, in association with induction of p21 in rat epidermal keratinneytes.The above data suggest that over-expression of wild-type p53 and p21 may play an important role in preventing the carcinogenesis from damage of UVB.

Key words: Ultraviolet rays, Keratinocytes, Protein p53, Oncogene protein p21