Fig. 3.

Aged human skin fibroblasts are resistant to DNA damaging agents. a HFSN1 cells were either mock-treated or challenged with γ-rays (30 Gy), cisplatin (60 μg/ml), or UV light (10 J m⁻²) and then re-incubated for 72 h. Apoptosis was analyzed by annexin V/PI flow cytometry. b Histograms showing the proportions of spontaneous and induced apoptosis (early + late). The error bars represent standard deviations of at least three different experiments