Effect of thalidomide, octreotide, and prednisolone on the migration and proliferation of RPE cells in vitro

Purpose. The retinal pigment epithelium (RPE) is involved in the pathogenesis of age-related macular degeneration. The purpose of this study was to assess the effect of thalidomide, octreotide, and prednisolone on the proliferation and migration of bovine RPE cells in vitro. Methods. The migration assay was performed in double-chamber-wells separated by a membrane filter with 8 mu m pores. Cells were allowed to migrate vertically for 7 hr, afterwards the cells on both filtersides were fixed, stained, and the migrated cells were counted. To examine RPE proliferation, bovine RPE cells were seeded subconfluently followed by an incubation with octreotide, thalidomide or prednisolone in a concentration gradient for 24 hr. Stimulation or inhibition of DNA synthesis was measured by [H-3]-thymidine incorporation. Statistical analysis was performed with the paired student's t-test. Results. Statistically significant (p < 0.05) inhibition of RPE cell proliferation was measured for thalidomide at a concentration of 10-50 mu g/ml, for octreotide at a concentration of 5 x 10(-4) and 5 x 10(-5) M, and for prednisolone at a concentration of 250 and 500 mu g/ml as compared to the negative control. RPE cell migration was significantly (p < 0.05) inhibited by thalidomide at a concentration of 10 mu g/ml, by octreotide at a concentration of 5 x 10(-5) M, and also by prednisolone at a concentration of 500 mu g/ml as compared to the negative control. Conclusions. Although the main effect of thalidomide, octreotide, and prednisolone when treating patients with choroidal neovascular membranes is probably related to the inhibition of angiogenesis it should be kept in mind that these substances may additionally inhibit RPE proliferation and migration.