Figure 3. AREG and GDF 15 protein level in conditioned media of UVB-exposed cells. SRA01/04 cells were irradiated at indicated energies of UVB. The conditioned media were collected after 12 h and 24 h, and were examined for AREG and GDF15 ELISA assays. Values are expressed as the mean±average deviation in biologic duplicate determinations. Solid triangle and square were AREG protein level at 12 h and 24 h, respectively. Open triangle and square were GDF15 protein level at 12 h and 24 h, respectively. Essentially the same results were obtained with three independent experiments, and representative data are shown. **p<0.01; *p<0.05, compared to control conditioned media (sham-irradiated culture).