Fig. 5

PDA NPs relieve UVR-induced inflammation. (A, B) Representative immunofluorescent images and quantification of MPO signal in the dorsal skin of Balb/c mice after different experimental treatments (n = 4). MPO was stained with Cy3 (red) and nuclei were stained with Hoechst 33,258 (blue). (C) The MPO protein level of HaCaT cells was detected after being pretreated with different concentrations of PDA NPs (0, 20, 40, and 60 mg/mL) for 24 h, followed by exposure to UVR. (D) Semi-quantitative analysis of p53 was normalized to GAPDH. (E-H) The mRNA expression levels of TNF-α, IL-1β, IL-,6 and IL-8 of HaCaT cells were detected by qRT-PCR after being pretreated with different concentrations of 60 mg/mL PDA NPs for 24 h, followed by exposure to UVR. The mRNA expression levels of these genes were normalized to β-actin. (I) The expression levels of TNF-α and IL-1β or β-Tubulin (as an internal control) were determined by western blotting. (J, K) The TNF-α and IL-1β protein level was detected in the lysates extracted from skin biopsies of Balb/c mice in different groups and quantified via normalization to β-Tubulin (n = 3). (L, M) The secretion of IL-6 and IL-8 in supernatants of HaCaT cells after indicated treatments was detected by their ELISA kit. All data represent the mean ± SD. *p < 0.05, **p < 0.01 and ***p < 0.001