Abstract: Objective: To determine the protective effects of paeoniflorin on HaCaT cells apoptosis induced by UVB. Methods: HaCaT cells were divided into eight groups (from group A- to group H). HaCaT cells in group A was used as control. Those in group B were treated with UVB irradiation only and those in group C-H were treated with different dose (0.25mg/L, 0.5 mg/L, 1 mg/L,2.5 mg/L, 5 mg/L and 10 mg/L) of paeoniflorin and UVB. The apoptosis was detected by the flow cytometry assay. The expression level of P21mRNA was detected by RT-PCR. Results: The apoptosis rate of HaCaT cells in group B was 4.840±0.836, which was higher than those in group C-G（0.423±0.179, 1.127±0.535, 1.633±0.417, 2.570±0.439, 3.137±0.347, respectively）(P<0.05). There was no significant difference in the apoptosis rate of HaCaT cells between group B and group H (P>0.05). The expression of P21mRNA in the group B was 1.040±0.007, which was higher than those in group C-H (0.440±0.015, 0.551±0.013, 0.857±0.017, 0.848±0.027, 0.850±0.052, 0.923±0.035, respectively) (P<0.05). Conclusion: Paeoniflorin has a protective effect on the apoptosis of HaCaT cells induced by UVB, and reduces the expression of P21mRNA of HaCaT cells at a certain concentration (0.25~5 mg/L).

Key words: paeoniflorin, UVB, HaCaT cell