title: All-trans retinoic acid promotes the repair of tortuosity of elastic fibres in rat skin.
abstract: To elucidate the repair effects of all-trans retinoic acid (t-RA) on ultraviolet (UV)-induced tortuosity of elastic fibres in rat skin, the hind limbs of Sprague-Dawley rats were irradiated at a suberythemal dose of UV (three times/week for 6 weeks) and 0.025% t-RA in ethanol was applied topically five times/week for 6 weeks. The three-dimensional arrangement of elastic fibres with special reference to their linearity was quantified by image analysis using a scanning electron microscope following a combination of intravascular resin injection and selective digestion using formic acid. When t-RA was topically applied for 6 weeks on wrinkles formed by 6 weeks' exposure of the skin of rat hind limbs to UV radiation, the wrinkles disappeared to control levels, concomitant with an improvement in skin elasticity. The linearity of the elastic fibres was significantly (P < 0.01) increased compared with age-matched UV-irradiated controls. These findings suggest that the degeneration and deposition of elastic fibres accompanied by an increase in their linearity is involved in the process of wrinkle repair by topical application of t-RA.
authors.affiliation: Biological Science Laboratories, Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi 321-3497, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tsukahara
authors.forename: Y
authors.initials: Y
authors.lastname: Takema
authors.forename: T
authors.initials: T
authors.lastname: Fujimura
authors.forename: S
authors.initials: S
authors.lastname: Moriwaki
authors.forename: T
authors.initials: T
authors.lastname: Kitahara
authors.forename: S
authors.initials: S
authors.lastname: Imayama
authors.forename: G
authors.initials: G
authors.lastname: Imokawa
mesh_terms: D000287:Administration, Topical; D000818:Animals; D004548:Elasticity / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology; D006614:Hindlimb; D007641:Keratolytic Agents / Q000627:therapeutic use*; D008297:Male; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects / Q000648:ultrastructure; D015595:Skin Aging / Q000187:drug effects*; D012879:Skin Physiological Phenomena; D014212:Tretinoin / Q000627:therapeutic use*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D007641:Keratolytic Agents; D000431:Ethanol; D014212:Tretinoin