Abstract: Objective To explore the effects of ultraviolet B (UVB) on signal transduction pathway of HaCaT cells.Methods HaCaT cells,an immortalized human keratinocyte cell line,were irradiated with 40 mJ/cm² UVB,the cellular and nuclear protein of HaCaT cells was isolated and collected at 0,10,30,60,120,240 min after the irradiation.Western blot was performed to detect the dynamic changes of phosphorylated-IkB-α,IκB-αand NF-κB p65 protein in the nuclei,and the phosphorylation status of MAPK proteins including ERK1/2,p38,c-JNK.Results As shown by the Western blott,the phosphorylation and degradation of IkB-αbegan at 0.5 h,and became more noticeable at 2 h and 4 h,after the UVB irradiation.The level of p65 protein began to increase at 0.5 h,and peaked at 2h after the irradiation.The phosphorylation of ERK1/2,p38,c-JNK increased dramatically as early as 10 min after the UVB irradiation.Conclusion UVB can activate the intracellular signal transduction pathway of MAPK and NF-κB in keratinocytes.

Key words: Ultraviolet rays, Keratinocytes, Signal transduction