Figure 1. Increased 8-hydroxy-2’-deoxy-guanosine in the aged retinal pigment epithelium and choroid. Immunolabeling for 8-hydroxy-2’-deoxy-guanosine (8-OHdG) of retinal pigment epithelium (RPE) and choroid from from young mice (5 month, A), young rats (5 month, C) compared to old mice (22 month, B) and old rats (26 month, D). The labeling intensity of 8-OHdG was higher in the old RPE and choroid from mice (B) and rats (D), compared to the young RPE and choroid (A and C). Scale bar equals 20 µm. The oxidative DNA adduct, 8-OHdG, in rat RPE and choroid was quantitatively measured by 8-OHdG ELISA (E). There was a significant increase (p=0.007, n=6) in the amount of 8-OHdG in aged RPE and choroid.