In vitro protection against hydrogen peroxide-induced oxidative stress and cell death in ARPE-19 cells by Curcumin

Curcumin, the main active phenolic compound present in turmeric, possesses a wide range of pharmacological properties including antioxidant activities [1]. Although the exact etiology of age-related macular degeneration (AMD), the leading cause of blindness in the elderly, is not known, the retinal pigment epithelium (RPE) is considered a primary target via oxidative cell damage [2]. The purpose of this study is to determine if curcumin protects RPE cells against H₂O₂-induced oxidative stress and cell death. Cultured RPE cells (ARPE-19) were pretreated with curcumin (25–100µM) for 1h before washing and incubation with H₂O₂ (100–600µM) for 24h. The percentage of viable cells was determined using trypan blue dye exclusion. Nuclear chromatin condensation, a hallmark of apoptosis, was determined using Hoechst 33342 staining and then visualized by fluorescence microscopy. The results demonstrated that treatment of ARPE-19 with H₂O₂ resulted in dose-dependent cell death and an increase in the number of cells containing condensed nuclei in a time-dependent manner. Pretreating cells with 100µM curcumin for 1h prior exposure to 600µM H₂O₂ notably attenuated cell death and decreased the percentage of cells containing condensed nuclei. These results indicate that in vitro, curcumin provides substantial protection against H2O2-induced cell death and nuclear condensation in ARPE-19 cells and may therefore, be useful as a potential agent in the treatment of disorders associated with oxidative stress-induced cell damage such as AMD.

Acknowledgements: This work was supported partially by research grants from Suranaree University of Technology and Mahidol University.

References: 1. Sharma, OP. (1976) Biochem. Pharmacol. 25:1811–1812.

2. Winkler, BS. et al. (1999) Mol. Vis. 5:32.