Figure 2. (A) Schematic representation of the protocol for senescence induction using UVB irradiation. Cells were treated -/+ the compounds from day 1 to 7 after seeding, irradiated with UVB on days 2 and 5 and harvested for analysis on day 7. (B) Senescence assay results including β-Gal staining and HAS2 gene expression analysis for cells treated with each compound. The results are shown by arrows that indicate increase/decrease (↑, ↓) and hyphens that indicate no effect (-). (C) Phase-contrast (left column) and bright field (right column) microscope images of SA-β-Gal staining showing non-irradiated cells, UVB-irradiated cells non-treated and treated with Gallic acid or Shikimic acid at the indicated concentrations. (D) Percentage of SA-β-Gal positive cells and (E) Relative HAS2 mRNA levels in non-irradiated cells, UVB-irradiated cells and UVB-irradiated cells treated with Gallic acid or Shikimic acid at the indicated concentrations. Student T-test, *p<0.05, **p<0.01, ***p<0.001.