Figure 5. The effect of passage-related senescence on retinal pigment epithelium (RPE) cytokine and growth factor secretion. A: Secreted cytokine levels were expressed as fold changes (mean±SEM): Those predominantly in late passage cultures were given
positive values; those predominantly in early passage cultures were given negative values. IL-1ra was overexpressed, while
SDF-1α, GM-CSF, IL-8, IL-15, and IL-6 were downregulated in late passage (P21) RPE cells compared to early passage (P5) RPE
cells. The changes reached a significance level of p<0.05 and a cut-off fold of 1.5. B: The changes in cytokine and growth factor secretion were compared between late passage (P21) and early passage (P5) RPE.