Inhibitive effect of genistein on interleukin-8 expression in cultured human retinal pigment epithelial cells.

Recent studies showed that interleukin-8 (IL-8) played an important role in retinal neovascularization. In this study, the effects of genistein on the expression of IL-8 in the arising retinal pigment epithelia-19 cells were studied. The levels of IL-8 protein expression in supernatants were punctually detected by ELISA. When the cells were treated with hypoxia (5% CO2, 95% N2), IL-8 secretion increased from 0.29 +/- 0.04 to 2.59 +/- 0.42 ng/ml. To study calcium-dependent IL-8 expression, cells were treated with KCl at 25 mM, norepinephrine (NE) at 10 nM, and glutamate (Glu) at 1 microM for 8 h. As a result, the levels of IL-8 protein in supernatants were significantly increased compared with that in the controls. When the cells are treated with genistein (50, 100, 200 microM) for 30 min before hypoxia or stimulations by KCl, NE, and Glu, the elevated expression of IL-8 protein was all suppressed in a concentration-dependent manner. These results suggested that suppression of IL-8 expression in retinal pigment epithelial cells might partly account for the inhibitive effect of genistein on retinal neovascularization. Copyright 2006 Prous Science.