Figure 3. HucMSC-ex reduced UV-induced ROS production in vitro. (A) Western blot was used to detect the expression level of cleaved-PARP and p-NF-κB after different intensity of UV treatment. (B) Confocal microscopy observation of the internalization of PKH-67 labeled hucMSC-ex co-incubated with HaCaT for 12 hours. Original magnification (600x). (C) ROS production was detected by inverted fluorescence microscope after 500mJ UVB treatment of HaCaT cells (200x). (D) Crystal violet detected cell proliferation activity after HaCaT cells treatment with different concentration of H2O2. (E) Western blot analysis of Bax and p-NF-κB expression after HaCaT cells treatment with different concentrations of H2O2. (F) Western blot was used to detect the expression level of inflammatory cytokines and apoptosis in HaCaT cells treated with H2O2 at different times. (G) Western blot detection of 53BP1 expression level of H2O2 after HaCaT cells treatment at different times.