title: Optical detection of singlet oxygen produced by fatty acids and phospholipids under ultraviolet A irradiation.
abstract: Ultraviolet A (UVA) radiation has been known to generate reactive oxygen species, such as singlet oxygen, in skin, leading to the oxidation of lipids and proteins. This oxidation influences cellular metabolism and can trigger cellular signaling cascades, since cellular membranes and the stratum corneum contain a substantial amount of fatty acids and lipids. Using highly sensitive IR-photomultiplier technology, we investigated the generation of singlet oxygen by fatty acids and lipids. In combination with their oxidized products, the fatty acids or lipids produced singlet oxygen under UVA radiation at 355 nm that is directly shown by luminescence detection. Linolenic or arachidonic acid showed the strongest luminescence signals, followed by linoleic acid and docohexaenoic acid. The amount of singlet oxygen induced by lipids such as phosphatidylcholine was significantly higher compared to the corresponding fatty acids within phospholipids. This result indicates a synergistic process of oxygen radicals and singlet oxygen during irradiation. UVA radiation initiates singlet oxygen generation, which subsequently oxidizes other fatty acids that in turn produce additional singlet oxygen. This leads to an enhancement of UVA-induced damage of fatty acids and lipids, which must enhance the oxidative damages in cells.
authors.affiliation: University of Regensburg, Department of Dermatology, 93042 Regensburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Baier
authors.forename: Tim
authors.initials: T
authors.lastname: Maisch
authors.forename: Johannes
authors.initials: J
authors.lastname: Regensburger
authors.forename: Claudia
authors.initials: C
authors.lastname: Pöllmann
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bäumler
mesh_terms: D005227:Fatty Acids / Q000737:chemistry* / Q000528:radiation effects*; D010743:Phospholipids / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry* / Q000528:radiation effects*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D005227:Fatty Acids; D010743:Phospholipids; D026082:Singlet Oxygen