AIM:To investigate the effects of resveratrol ( Res) on the proliferation of ARPE-19 cells and to ex-plore the possible mechanisms.METHODS:After ARPE-19 cells were treated with Res at concentrations of 0, 50, 100, 150, 200 and 300 μmol/L for 24 h, 48 h and 72 h, the effects of Res on the proliferation of the cells were tested by CCK-8 assay.The ARPE-19 cells were treated with Res at concentrations of 0, 100, 150 and 200 μmol/L for 48 h.The effects of Res on the cell cycle and apoptosis were detected by flow cytometry with Annexin V-FITC/PI staining.The protein expression of proliferating cell nuclear antigen (PCNA) was detected by immunofluorescent assay.The mRNA expression of PCNA, P21 and P27 was determined by real-time PCR.RESULTS:The results of CCK-8 assay showed that Res inhibited the prolifera-tion of ARPE-19 cells in a time-and dose-dependent manner.The treatment with Res for 48 h resulted in an arrest of cell cycle at S phase without increasing cell apoptosis.Res inhibited the protein expression of PCNA in ARPE-19 cells.The re-sults of real-time PCR showed that Res increased the mRNA expression of P21 and P27, and decreased the mRNA expres-sion of PCNA.CONCLUSION: Res inhibits the proliferation of ARPE-19 cells and induces the cell cycle arrest at S phase.The mechanism may be related to up-regulation of P21 and P27, and down-regulation of PCNA.