Research Paper Volume 11, Issue 3 pp 950—973

Figure 1. Replicative senescence of TIG-3 cells. Cumulative (A) and individual (B) population doubling level (PDL) of TIG-3 cells were measured. (C) Pictures of SA-β-Gal positive cells (blue) at passage25 (P25) and 39 (P39) were taken. Scale bars represent 100 μm. (D) The percentage of SA-β-Gal positive cells were quantified at different passages. (E) p21^CIP1 (upper panel) and p16^INK4a (bottom panel) genes expression at different passages were analyzed by qPCR. The lowest expression level was set to 1. Three independent proliferation assays were performed. n.s., not significant, *p<0.05, ***p<0.001, compared to each lowest passage for (D) and (E), by Student’s two-tailed t test.