Figure 1. Characterisation of senescence in human dermal fibroblasts (HDFs). (A) Hayflick proliferation curve for human dermal fibroblasts (HDFs) from early proliferation (EP) to deep senescence (DS) through serial cell culture. N = 2–6. (B) Immunofluorescence staining of DAPI (blue) and Ki67 (green) in EP and DS HDFs. N = 2. Scale bar = 50 μm; (C) Immunofluorescence staining of DAPI (blue) and p21 (green) in EP and DS HDFs. N = 2. Scale bar = 50 μm (D) Immunofluorescence staining of DAPI (blue) and γ-H2AX foci (green) in EP and DS HDFs. N = 3. Scale bar = 50 μm. (E) Brightfield assessment of SA-β-Gal (blue) in EP and DS HDFs. N = 2. Scale bar = 100 μm.