Fig. 2. Effects of epigallocatechin gallate (EGCG) on intracellular reactive oxygen species (ROS) levels and cellular senescence in human dermal papilla cells (DPCs). (A) Human DPCs were grown with or without 10 µM EGCG and 10^–4 M dihydrotestosterone (DHT). To detect intracellular ROS levels, we performed 2',7'-dichlorofluorescein diacetate staining and detected cell cycle changes using a FACScalibur flow cytometer (BD Biosciences, San Jose, CA, USA). Changes in intracellular ROS levels were determined with the M1 gate. (B) Cells were treated with 10 µM EGCG or 10^–4 M DHT for 48 hours. Senescence was measured using senescence- associated β-gal assays. Senescence data are expressed as percentages of the senescence of the internal control (untreated sample) and are shown as the mean±standard error of the mean of three independent experiments. PI: propidium iodide (Sigma-Aldrich, St. Louis, MO, USA). ^#p<0.05 compared with vehicle, ^*p<0.05 compared with DHT.