Objectives: To investigate the effects of low-dose aminolevulinic acid photodynamic therapy (ALA-PDT) on photoaging in human dermal fibroblasts (HDFs) and to explore the mechanism of Nuclear factor erythroid 2-related factor 2(Nrf2)-mediated photorejuvenation in vitro.
Methods: A photoaging model was established through repeated exposure of HDFs to UVA. Total superoxide dismutase (SOD) expression was detected by a SOD activity assay. Nrf2 was knocked down through adenovirus infection, and successful knockdown was confirmed by Western blot analysis and quantitative polymerase chain reaction.
Results: Sustained exposure to UVA induced photoaging in HDFs. Total SOD activity was significantly increased by low-dose aminolevulinic acid (ALA)-PDT. Upon application of low doses of ALA-PDT to photoaging HDFs, Nrf2 was translocated to the nucleus; in addition, the expression of Nrf2, transforming growth factor-β1 (TGF-β1), type I and III collagen (COL1 and COL3), heme oxygenase 1 (HO-1), and p-ERK was increased, while the expression of matrix metalloproteinase 9 (MMP-9) was decreased. However, after Nrf2 was knocked down in HDFs, the expression of TGF-β1, COL1, COL3, and HO-1 was significantly decreased, while the expression of MMP-9 was increased.
Conclusion: This study revealed that low-dose ALA-PDT decreases UVA-mediated photoaging through an Nrf2-mediated antioxidant effect.
Keywords: ALA-PDT; HDFs; NF-E2-related factor 2 (Nrf2); Photoaging.
Copyright © 2019. Published by Elsevier B.V.