Objective To investigate proliferating cell nuclear antigen (PCNA) gene expression in retinal pigment epithelium (RPE) cells and inhibition of antisense oligonucleotides(AS-OND) encoding PCNA mRNA to gene expression and proliferation of RPE cells, so as to search for new genetic therapy way for pro1iferative vitreoretinopathy (PVR). Methods (1) Rabbit RPE cells cultured in vitro were detected for PCNA expression by streptoavidin-biotin-enzyme complex (SABC) immunohistochemistry at several times. (2) The liposome-mediated synthetic antisense oligodeoxynucleotides (AS-ODN) and sense oligodeoxynucleotides (S-ODN) encoding PCNA were delivered to the RPE cells at different concentrations, then PCNA expresstion were detected by immunohistochemistry. (3) Exposed to different concentrations of AS-ODN and S-ODN, growth activity and suppressive rate of RPE cells were measured by methyl thiazolyl tetrazolium (MTT) methods. Results (1) PCNA were expressed in RPE cells, culmination in 48 hours of culture. (2) PCNA expression were markedly suppressed in the RPE cells treated with 0.28 and 1.12 μmol/L PCNA AS-ODN. (3) 0.28 μmol/L and 1.12 μmol/L PCNA AS-ODN significantly inhibited proliferative activity of RPE cells in a dose-dependent manner, the arrest rates of cellular growth reached 53% and 81% respectively. Conclusion AS-ODN complementary to PCNA mRNA at some concentration can sequence-specifically suppress PCNA expression in RPE cells and cellular proliferative activity, and show potential application to further experimental study for PVR genetic medication. (Chin J Ocul Fundus Dis, 2002, 18: 231-233)