Objective: To study the protective effect of glycyrrhizin on light aging of human keratinocytes (HaCaT) cells induced by ultraviolet B (UVB) and relevant cytokines. Method: Different concentrations of glycyrrhizin were used to treat HaCaT cells. Methyl thiazolyl tetrazolium (MTT) was used to screen the effective and safe concentration of glycyrrhizin. The light aging model was set up through the irradiation of ultraviolet radiation B (UVB) at the irradiation dose of 30 mJ·cm-2

the activity of cells was determined by MTT method. The test kits were tested to determine the effect of glycyrrhizin on glutathione peroxidase (GSH-Px)

catalase (CAT) and lactate dehydrogenase (LDH) in each group of cells. Western blot method was used to detect the effect of glycyrrhizin on interleukin-1β (IL-1β)

IL-6 and tumor necrosis factor-α (TNF-α) protein expressions. Result: The optimum effective concentrations of glycyrrhizin were 1×10-7

1×10-6

1×10-5 mol·L-1. Compared with the blank group

the cell proliferation rate of the UVB group significantly decreased (P<0.01); the activities of GSH-Px and CAT were significantly decreased

the activity of LDH was significantly increased (P<0.01); the expressions of IL-1β

IL-6 and TNF-α were increased (P<0.05

P<0.01). Compared with the UVB group

the cell proliferation rate of 1×10-7

1×10-6

1×10-5 mol·L-1 glycyrrhizin+UVB group was significantly increased (P<0.01); the activities of GSH-Px and CAT were significantly increased

the activity of LDH was significantly decreased (P<0.01); the expressions of IL-1β

IL-6 and TNF-α were decreased (P<0.05

P<0.01). Conclusion: Glycyrrhizin can improve the activities of GSH-Px and CAT

reduce the activity of LDH

decrease the secretion of cytokines

and thus inhibit light aging of HaCaT cells induced by UVB.