Abstract: Objective To study the effects of tanshinone on the cultured immortalized human sebocytes and explore the mechanism of action of tanshinone in the treatment of acne. Methods MTT assay was applied to determine the effects of cryptotanshinone and tanshinone ⅡΑ at different concentrations on the proliferation of SZ95 sebocytes in 24 h, 48 h and 72 h after incubation. Lipid contents labeled with Nile red in SZ95 cells were analyzed by flow cytometry technique, and the expression of androgen receptor (AR) mRNA of SZ95 cells were detected by RT-PCR. Results Both cryptotanshinone and tanshinoneⅡΑ inhibited the proliferation of SZ95 cells in a dose-and time-dependent mode, with the 50% inhibition concentration (IC50) of 7.473 μmol/L (in 48 h) and 2.146μmol/L (in 72 h) for cryptotanshinone and 6.021 μmol/L (in 48 h) and 2.25 μmol/L (in 72 h) for tanshinone ⅡΑ. Additionally, as compared with the control group, the lipid content of SZ95 cells exposed to tanshinone ⅡΑ at 0.125μmol/L was decreased in 48h (P<0.05), and cryptotanshinone at 1μmol/L and 0.1μmol/L and tanshinoneⅡΑ at 1μmol/L decreased AR mRNA expression in SZ95 cells in 24h (P<0.01, P<0.01, P<0.05 respectively). Conclusions These results indicate that tanshinone can directly inhibit the proliferation and lipid synthesis of sebocytes and has indirect anti-androgen activity by down-regulating AR mRNA expression in sebocytes, which implicates its possible mechanism of action in treating acne.

Key words: Sebaceous glands, Cells, Cultured, Lipid, Receptor, androgen, Cryptotanshinone, Tanshinone