[Effect of various anti-glaucoma eyedrops on human corneal epithelial cells]

To investigate the effects of antiglaucoma eyedrops and vehicles on the proliferation of human corneal epithelial cells.

Seven eyedrops[prostaglandin F2 alpha analogs(2), beta blockers(40), topical carbonic anhydrase inhibitor(1)], and six of the eyedrop vehicles, excluding that of Xalatan, were used. Anti-glaucoma eyedrops and vehicles were serially diluted 2-fold with culture medium(10-2,560 fold). The mixture was added to human corneal epithelial cells and incubated for 48 hrs. Cell proliferation was measured by commercial assay kit. Dye-reagents were added to the wells and incubated for 1 h at 37 degrees C. Optical density were measured at 490 nm. The dilution rate for 50% inhibition was calculated as the dilution rate of drugs or vehicles necessary to produce 50% inhibition of cell proliferation.

All drugs completely inhibited cell proliferation when the dilution rate was low. At 40-fold dilution, Trusopt and Timoptol showed a significant decrease in cell growth inhibition. On the other hand, Rescula showed almost 100% inhibition at 160-fold dilution. Above 640-fold dilution, the inhibition rate of all drugs became 50% or less and there was no significant difference between drugs. Vehicles also inhibited cell growth. The dilution rates for growth inhibition by vehicles were different from those of drugs. The dilution rate at 50% inhibition of anti-glaucoma eyedrops decreased in the following order: Rescula > Xalatan > Betoptic > Hypadil > Mikelan > Timoptol > Trusopt. The dilution rate for 50% inhibition of vehicles decreased in the following order: Rescula vehicle > Hypadil vehicle > Betoptic vehicle > Mikelan vehicle > Timoptol vehicle > Trusopt vehicle.

All anti-glaucoma eyedrops inhibited cell proliferation. These effects were stronger in prostaglandin F2 alpha analogs and weakest in Trusopt. Furthermore, the inhibition of cell proliferation was caused also by the vehicle of eyedrops, and the influence of the vehicle varied in each type of eyedrops.