Figure 1. Proliferation affected by seeding density and culture time.

(A) ARPE-19 cells in DMEM/F-12 medium with 10% FBS (FBS) or serum-free (SF) were seeded at 1 × 10⁴/cm², 2 × 10⁴/cm², and 3 × 10⁴/cm² and incubated for 24–120 h. Proliferation was assayed with BrdU labeling (4 h) followed by BrdU ELISA. (B,C) The same as A except that cells were seeded at 0.25 × 10⁴/cm², 0.5 × 10⁴/cm², and 1 × 10⁴/cm² in DMEM/F-12/10% FBS (B) or DMEM/F-12/SF (C) and stimulated with EGF (10 ng/ml) and FGF-2 (20 ng/ml) (EGF + FGF-2) for 48 h. (n = 4, *indicates p < 0.05 when compared at the same cultivation time (A) or compared with the lower density in the same treatment group or at the same density between groups treated with PBS and EGF + FGF-2 (B,C).