Effects of drugs on cellular proliferation in cultured iris pigment epithelial cells and retinal pigment epithelial cells.
In this study, iris and retinal pigment epithelial cells were cultured from porcine and various drugs including methionine-enkephalin, isoproterenol, dibutyryl cAMP, endothelin-1, dexamethasone and phorbol 12-myristate 13-acetate (PMA) were used to investigate their effects on both cellular proliferation in cultured porcine iris and retinal pigment epithelial cells. Cellular proliferation was estimated with 3H-thymidine uptake. It is indicated that both pigment epithelial cells possess epithelial-like morphology and abundant pigment granules in cells obviously. Following the iris pigment epithelial cells being treated with endothelin-1, the 3H-thymidine uptake in the cells was increased to 126% as compared with the control. However, the cellular proliferation was decreased to 83% when the cells were treated with isoproterenol. In the case of methionine-enkephalin, dibutyryl cAMP, dexamethasone and phorbol 12-myristate 13-acetate (PMA), the thymidine uptake in the iris pigment epithelial cells was not affected by above drugs. In the retinal pigment epithelial cells, the 3H-thymidine uptakes were increased to 145% and 146% when the cells were incubated with methionine-enkephalin, and isoproterenol, respectively. In the presence of dibutyryl cAMP, dexamethasone and phorbol ester (PMA), the cellular proliferation was inhibited to 83%, 73% and 85% respectively. However, endothelin-1 did not affect the cellular proliferation in retinal pigment epithelial cells. These results show that the morphological shapes of iris pigment epithelial cells are similar to retinal pigment epithelial cells. However, the cellular proliferation in both cells may be regulated by distinct mechanisms.