Figure 4. Analysis of 8-oxo-dG levels and p53 phosphorylation. HCE cells were incubated with PBS (clear square) or HMW-HA (black square) and irradiated with various doses (0, 25, 75, and 150 mJ/cm²) of UVB. The concentration of 8-oxo-dG excreted in the cell culture supernatant and quantification of serine 46-phosphorylated p53 were determined by ELISA 24 h after irradiation. A: The concentration of 8-oxo-dG excreted in the cell culture supernatant and B: quantification of serine 46-phosphorylated p53 were determined by ELISA 24 h after irradiation.Data are mean±SD of three independent experiments. Differences were significant at p<0.05 (one asterisk), p<0.01 (two asterisks), and p<0.001 (three asterisks) compared to the PBS group of each UVB dose.