Int J Biol Sci 2019; 15(10):2100-2109. doi:10.7150/ijbs.31583

Research Paper

5-aminolaevulinic acid-based photodynamic therapy inhibits ultraviolet B-induced skin photodamage

Hui Hua1*, Jia-wei Cheng1*, Wen-bo Bu2*, Juan Liu1, Wei-wei Ma1, Na Ni1, Jian Shi1, Bing-rong Zhou1✉, Dan Luo1✉

1. Department of Dermatology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China;
2. Institute of Dermatology, Chinese Academy of Medical Science and Peking Union Medical College, Nanjing, China.
*These authors contributed equally to this work.

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Hua H, Cheng Jw, Bu Wb, Liu J, Ma Ww, Ni N, Shi J, Zhou Br, Luo D. 5-aminolaevulinic acid-based photodynamic therapy inhibits ultraviolet B-induced skin photodamage. Int J Biol Sci 2019; 15(10):2100-2109. doi:10.7150/ijbs.31583. Available from

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To evaluate the photoprotective effect of 5-aminolaevulinic acid-based photodynamic therapy (ALA-PDT) on ultraviolet B (UVB)-induced skin photodamage. In vivo experiments, the dorsal skin of hairless mice were treated with ALA-PDT or saline-PDT, and then exposed to 180 mJ/m2 UVB. Results showed that the number of sunburn cells and apoptotic cells in the epidermis of ALA-PDT-treated groups at 24 h after UVB irradiation were significantly decreased compared with those in the UVB groups. And the removal rate of CPDs was obviously higher in ALA-PDT-treated groups. At 48 h, the number of Ki67 positive nuclei in ALA-PDT-UVB group was significantly fewer than that in UVB group. Further in vitro experiments, human keratinocyte cell line (HaCaT) cells of two groups (one treated with ALA-PDT, the other untreated), were exposed to 60 mJ/m2 UVB irradiation. We found 0.5 mmol/L of ALA and 3 J/cm2 of red light did not affect the vitality of cells, and could reduce UVB induced apoptosis, accelerate the clearance of CPDs, inhibit proliferation and activate p53. Thus, our data demonstrate that ALA-PDT pretreatment can induce a protective DNA damage response that protects skin cells from UVB-induced photodamages.

Keywords: photodamage, ultraviolet radiation, photodynamic therapy, DNA damage, CPDs, p53