Inhibition of cultured human retinal pigment epithelial cell by tissue-type plasminogen activator

PURPOSE: To study the inhibition effects of human retinal pigment epithelial (RPE) cells by tissue-type plasminogen activator(tPA). METHODS: The effects of tPA on human RPE cells proliferation were studied by viable cell counting and methyl thiazolyl tetrazolium (MTT) colorimetric assay. Flow cytometry (FCM) analysis was used to examine RPE cell cycles. RESULTS: The proliferation of human RPE cells could be inhibited by 0.1-3 micrograms/ml tPA (P < 0.05). The effects of inhibition were depended on the drug density and the action time directly (P < 0.01). 5 micrograms/ml tPA was deadly-toxic to human RPE cells. FCM revealed that the cells in S phase increased 9.8% (P < 0.05) and cells in G2M phase decreased 6.6% (P < 0.05), compared to controls. CONCLUSION: tPA at a certain dose range and period could inhibit human RPE cells proliferation without deadly-toxicity. The human RPE cells growth could be interfered in S phase by tPA.