Xu, Chunxia and Green, Adele and Parisi, Alfio and Parsons, Peter G. (2001) Photosensitization of the sunscreen octyl-p-dimethylaminobenzoate by UVA in human melanocytes but not in keratinocytes. Photochemistry and Photobiology, 73 (6). pp. 600-604. ISSN 0031-8655
Abstract
Sunscreens penetrate human epidermis and modify the biology of proliferating cells. This study addressed the question whether the UV response of cultured human cells is affected by direct treatment with nontoxic levels of sunscreens. Cell survival following exposure to UVC or unfiltered UVB was not altered by preincubation with 25 mg/mL of octyl p-dimethylaminobenzoate (o-PABA), 2-ethylhexyl p-methoxycinnamate (EHMC) or oxybenzone. However, UVA or UVB filtered to reproduce the solar UV spectrum penetrating to the basal layer of the epidermis, highly sensitized cells to killing by o-PABA but not by its hydrolysis product, 4-dimethylaminobenzoic acid. Sensitization was found in all cell types tested, except normal keratinocytes, and could be prevented by certain antioxidants particularly pyruvate and the hydroxyl radical scavenger mannitol. o-PABA and EHMC
applied without UV reduced the adherence of cells. The
results indicate that sunscreens may increase cell mobility
and the combination of o-PABA with solar UV may selectively damage melanocytes in the skin.
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