The effects of UVA and UVB irradiation on the viscoelastic properties of hairless mouse skin in vivo.
BACKGROUND
Age-related changes in the elasticity of the human skin have been demonstrated as well as those due to proto ageing.


OBJECTIVE
To investigate if UV irradiation causes similar changes in the elastic properties of skin, hairless mice (HR/ICR) were irradiated chronically with suberythemal doses of UVA or UVB. Using a recently designed, commercially available noninvasive in vivo instrument, we compared skin thickness and elasticity after 8 weeks of UV exposure with age-matched control mice.


RESULTS
Skin thickness increased significantly after UVB irradiation. Skin elasticity (Ur/Uf) decreased significantly after UVA and UVB irradiation, and the ratio of viscosity to elasticity (Uv/Ue) increased significantly after UVA irradiation. Intrinsic immediate strain (Ue*) and intrinsic delayed strain (Uv*) decreased significantly after UVB and UVA exposure. These changes were similar to those reported previously in an in vivo study on human face skin using the same instrument.


CONCLUSIONS
This finding suggests that the Ue* and Uv* changes observed in human facial skin are associated with actinic ageing caused by chronic UV exposure.
Takema
Y
Y
Biological Science Laboratories, Tochigi, Japan.
Imokawa
G
G
D000375:Aging / Q000528:radiation effects; D000818:Animals; D004195:Disease Models, Animal; D004548:Elasticity / Q000528:radiation effects; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000503:physiopathology / Q000528:radiation effects*; D012879:Skin Physiological Phenomena / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014783:Viscosity / Q000528:radiation effects