Abstract: Objective: To determine the effect of α-lipoic acid on human primary keratinocyte oxidative stress induced by UVB radiation. Methods: The oxidative stress model was established by H2O2 and UVB. The cell morphology and fluorescent intensity were observed under inverted microscope or fluorescence microscope. The intracellular ROS was detcted with fluorescent nuclear staining of 2'7'-acetyl chloride fluorescence sodium acetate (DCFH-DA). Green fluorescent was quantified by flow cytometry. The total antioxidant capacity of total antioxidant capacity (TAOC) and malonaldehyde (MDA) were measured by chemical method. Results: The fluorescence intensity and MDA in cells irradiated by UVB for 4hs were 35311±3072.3 and 11.61±0.68 nmol/mg·prot , which were higher than that in negative control group (24465±2085.3 and 8.25±1.21), with significant differences (Ps<0.05). After incubated 4hs with antioxidant LA, the fluorescence intensity and MDA were reduced to 26926±3502.7 and 9.14±1.12 vnmol/mg·prot. There was no significant difference in the level of TAOC between different groups. Conclusion: LA can alleviate the oxidative stress of the keratinocyte induced by UVB irradiation. 

Key words: keratinocyte, ultraviolet B, α-lipoic acid, oxidative stress