title: The formation of wrinkles caused by transition of keratin intermediate filaments after repetitive UVB exposure.
abstract: It has been reported that the formation of wrinkles involves changes in the elastic properties of the dermis due to the denaturation of elastic fibers. Several studies have shown that the hydration condition of the stratum corneum is also important in wrinkle formation. It is, however, still unclear how the stratum corneum contributes to wrinkle formation. Here we investigated the relationship between the formation of wrinkles and changes in the physical properties and condition of the skin after repetitive ultraviolet B (UVB) irradiation of hairless mice (HR/ICR). Repetitive UVB irradiation caused wrinkles on the dorsal skin of the mice. The elasticity (E') of the stratum corneum of UVB-irradiated mice was significantly lower than that of age-matched control (unirradiated) mice. UVB exposure also caused a deterioration of the fibrous ultrastructure of keratin intermediate filaments (KIFs) in the skin. We conclude that the deterioration of KIFs in the stratum corneum caused by repetitive UVB irradiation decreases the elastic properties of the stratum corneum, resulting in the formation of wrinkles.
authors.affiliation: Skin Care Research Laboratories, Kao Corporation, 2-1-3 Bunka Sumidaku, 131-8501, Tokyo, Japan. sano.tomohiko@kao.co.jp
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Sano
authors.forename: Takuji
authors.initials: T
authors.lastname: Kume
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujimura
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kawada
authors.forename: Shigeru
authors.initials: S
authors.lastname: Moriwaki
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Takema
mesh_terms: D000818:Animals; D004548:Elasticity; D004817:Epidermis / Q000502:physiology / Q000648:ultrastructure; D007382:Intermediate Filaments / Q000648:ultrastructure*; D007633:Keratins / Q000648:ultrastructure*; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D008813:Mice, Inbred ICR; D012867:Skin / Q000528:radiation effects* / Q000648:ultrastructure*; D015595:Skin Aging / Q000502:physiology*; D014466:Ultraviolet Rays
chemical_list: D007633:Keratins