title: Augmentation of UV-induced skin wrinkling by infrared irradiation in hairless mice.
abstract: Skin aging can be divided into intrinsic aging and photoaging. Sunlight is a major cause of photoaging, and is composed of ultraviolet (UV) and infrared (IR) radiation. Although the effects of UV radiation on skin aging have been widely studied, little is known about the biological effects of IR on the photoaging process in human skin. We found that chronic IR treatment induced wrinkles in hairless mice, and augments UV-induced wrinkle formation and UV-induced skin thickening in hairless mice. Histologically, we found that IR treatment augments UV-induced epidermal and dermal thickening, and that UV-induced increases of collagen and elastic fibers in dermis. Moreover, chronic IR treatment increased MMP-3 and MMP-13 mRNA expressions significantly in hairless mouse skin and augmented UV-induced MMP-3 and MMP-13 mRNA expressions and UV-induced MMP-2 and MMP-9 activities. From these results, we demonstrate that IR alone induces skin wrinkling and augments UV-induced wrinkle formation. Taken together, we suggest that IR plays an important role in the development of photoaging.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Laboratory of Cutaneous Aging Research, Clinical Research Institute, Seoul National University Hospital, 28, Yongon-dong, Chongno-Gu, Seoul 110-744, Republic of Korea.
authors.forename: Hyeon Ho
authors.initials: HH
authors.lastname: Kim
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Lee
authors.forename: Se Rah
authors.initials: SR
authors.lastname: Lee
authors.forename: Kyu Han
authors.initials: KH
authors.lastname: Kim
authors.forename: Kwang Hyun
authors.initials: KH
authors.lastname: Cho
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Eun
authors.forename: Jin Ho
authors.initials: JH
authors.lastname: Chung
mesh_terms: D000818:Animals; D005260:Female; D006801:Humans; D007259:Infrared Rays; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000033:anatomy & histology / Q000473:pathology / Q000528:radiation effects; D015595:Skin Aging / Q000473:pathology / Q000528:radiation effects*; D014466:Ultraviolet Rays