title: A reasonable mechanism for visible light-induced skin rejuvenation.
abstract: In recent years, much research has been done in the field of non-ablative skin rejuvenation. This comes as a response to the continuous demand for a simple method of treating rhytides, UV exposure, and acne scars. Numerous researches involve visible light-pulsed systems (20-30 J/cm(2)). The mechanism of action is believed to be a selective heat-induced denaturalization of dermal collagen that leads to subsequent reactive synthesis (Bitter Jr., Dermatol. Surg., 26:836-843, 2000; Fitzpatrick et al., Arch. Dermatol., 132:395-402, 1996; Kauvar and Geronemus, Dermatol. Clin., 15:459-467, 1997; Negishi et al., Lasers Surg. Med., 30:298-305, 2002; Goldberg and Cutler, Lasers Surg. Med., 26:196-200, 2000; Hernandez-Perez and Ibeitt, Dermatol. Surg., 28:651-655, 2002). In this study, we suggest a different mechanism for photorejuvenation based on light-induced reactive oxygen species (ROS) formation. We irradiated collagen in vitro with a broadband of visible light (400-800 nm, 24-72 J/cm(2)) and used the spin trapping coupled with electron paramagnetic resonance spectroscopy to detect ROS. Irradiated collagen resulted in hydroxyl radicals formation. We propose, as a new concept, that visible light at the energy doses used for skin rejuvenation (20-30 J/cm(2)) produces high amounts of ROS, which destroy old collagen fibers, encouraging the formation of new ones. On the other hand, at inner depths of the skin, where the light intensity is much weaker, low amounts of ROS are formed, which are well known to stimulate fibroblast proliferation.
authors.affiliation: Department of Chemistry, Bar-Ilan University, Ramat-Gan, 52900, Israel.
authors.forename: Rachel
authors.initials: R
authors.lastname: Lubart
authors.forename: Harry
authors.initials: H
authors.lastname: Friedmann
authors.forename: Ronit
authors.initials: R
authors.lastname: Lavie
authors.forename: Leonardo
authors.initials: L
authors.lastname: Longo
authors.forename: Julia
authors.initials: J
authors.lastname: Jacobi
authors.forename: Ohad
authors.initials: O
authors.lastname: Baruchin
authors.forename: Abraham M
authors.initials: AM
authors.lastname: Baruchin
mesh_terms: D003094:Collagen / Q000528:radiation effects*; D004578:Electron Spin Resonance Spectroscopy; D010789:Phototherapy / Q000379:methods*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012060:Rejuvenation; D015595:Skin Aging / Q000528:radiation effects*
chemical_list: D017382:Reactive Oxygen Species; D003094:Collagen