title: Ovariectomy is sufficient to accelerate spontaneous skin ageing and to stimulate ultraviolet irradiation-induced photoageing of murine skin.
abstract: BACKGROUND
  Wrinkling and sagging of the skin during photoageing is physiologically associated with diminished elasticity, which can be attributed to increased fibroblast-derived elastase activity. This degrades the dermal elastic fibres needed to maintain the three-dimensional structure of the skin. We previously reported that ovariectomy accelerates ultraviolet (UV)B-induced wrinkle formation in rat hind limb skin by altering the three-dimensional structure of elastic fibres.
  
  
  OBJECTIVE
  In this study, we used hairless mice to assess the effects of ovariectomy with or without chronic UVA or UVB radiation on sagging and wrinkling of skin, on the elasticity of skin, as well as on matrix metalloproteinase activities in the skin.
  
  
  METHODS
  Ovariectomies or sham operations were performed on 6-week-old female ICR/HR hairless mice.
  
  
  RESULTS
  Even in the ovariectomy group without UV irradiation, the skin elasticity was significantly decreased during the 3-13 weeks after ovariectomy, which was accompanied by a significant increase in elastase activity in the skin. After UVA or UVB irradiation, skin elasticity was significantly decreased to a greater extent in the ovariectomy group than in the sham operation group, and this was accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV in the skin. Consistent with the decreased skin elasticity, UVA irradiation for 12 weeks elicited more marked sagging in the ovariectomy group than in the sham operation group. UVB irradiation for 12 weeks also induced more marked wrinkle formation in the ovariectomy group than in the sham operation group.
  
  
  CONCLUSIONS
  These results suggest that ovariectomy alone is sufficient to accelerate skin ageing and to increase UV sensitivity, which results in the further deterioration of the skin and photoageing, and may account for the accelerated skin ageing seen in postmenopausal women.
authors.affiliation: Department of Dermatology, Jichi Medical School, Tochigi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Tsukahara
authors.forename: H
authors.initials: H
authors.lastname: Nakagawa
authors.forename: S
authors.initials: S
authors.lastname: Moriwaki
authors.forename: S
authors.initials: S
authors.lastname: Kakuo
authors.forename: A
authors.initials: A
authors.lastname: Ohuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Takema
authors.forename: G
authors.initials: G
authors.lastname: Imokawa
mesh_terms: D000818:Animals; D004548:Elasticity / Q000528:radiation effects; D004967:Estrogens / Q000502:physiology; D005260:Female; D007091:Image Processing, Computer-Assisted; D051379:Mice; D008812:Mice, Hairless; D008813:Mice, Inbred ICR; D010052:Ovariectomy; D010196:Pancreatic Elastase / Q000378:metabolism; D012867:Skin / Q000201:enzymology / Q000528:radiation effects; D015595:Skin Aging / Q000502:physiology* / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D004967:Estrogens; D010196:Pancreatic Elastase