To evaluate the effects of oxidative stress and antioxidantson heme oxygenase-1 (HO-1) in cultured human retinal pigment epithelial (RPE) cells.

Cultured RPE cells were challenged with different concentrations of hydrogen peroxide (H₂O₂), and the HO-1 mRNA level was determined by RT-PCR after 24 hours and 48 hours of incubation independently. Additionally, the HO-1 mRNA level was measured after preincubating RPE cells with N-acetylcystein (NAC) as the antioxidant for 30 minutes and then challenging the cells with H₂O₂.

The expression of the HO-1 mRNA level increased after H₂O₂ exposure, and this level was proportional to the increased H₂O₂ concentration ( p <0.05). Expression of the HO-1 mRNA level decreased when the RPE cells were preincubated with NAC ( p <0.05).

In human RPE cells, the HO-1 level increased in proportion to the degree of oxidative stress and decreased with exposure to antioxidants. Expression of HO-1 may be helpful in preventing retinal disease, which occurs due to oxidative stresses such as age-related macular degeneration.