Zinc Induced Cell Death in Human Retinal Pigment Epithelial Cell, and its Relationship with Reactive Oxygen Species

Abstract

Abstract: : Purpose: Zinc, an essential nutrient, is one of the most abundant trace element in the eye. It has been involved in the induction , maintenance and inhibition of apoptotic cell death.Here we sought to investigate the mechanism of apoptotic cell death induced by zinc in human RPEs. Methods: Retinal pigment epithelium ARPE-19 cells were obtained from the American Type Culture Collection. Cell viability was measured by MTT assay. Apoptosis assay was performed by TUNEL assay and Annexin V-FITC binding assay. The formation of intracellular ROS was measured using 2’,7’-dichlorofluorescein diacetate (DCFH-DA). Western blot analysis was performed to measure p53 level. Results: Zinc at concentrations of 100 µM induced apoptosis in RPE cells. Reactive oxygen species (ROS) and p53 protein were significantly increased by zinc induction. Therefore, we sought to determine whether the expression of p53 is related to the levels of intracellular ROS. In RPE cells, both ROS production and apoptosis were inhibited by antioxidant treatment (NAC). The level of p53 was also reduced by antioxidant treatment. Conclusions: These results suggest that p53 might be involved in zinc-induced apoptosis by a pathway that is dependent on ROS production in human RPE cells.

Keywords: retinal pigment epithelium • apoptosis/cell death • molecular biology