Figure 6. IL-1ra immunoreactivity in RPE of older versus younger human donor eyes. Immunoreactivity for IL-1ra was developed with VIP (purple) and counterstained with methyl green (green; scale bar: 20 μm). A: Representative picture of IL-1ra in RPE from a 72-year-old donor eye. B: Representative picture of IL-1ra in RPE from a 54-year-old donor eye. C: Negative control by primary antibody omission. D: IL-1ra was more expressed in RPE from older donor eyes (≥70 years old, n=12) compared with that from younger donor eyes (≤55 years old, n=11). (mean±SEM, *: p<0.01)