Enhancing effect of ultraviolet A on ornithine decarboxylase induction and dermatitis evoked by 12-o-tetradecanoylphorbol-13-acetate and its inhibition by curcumin in mouse skin.
BACKGROUND
Previous studies have demonstrated appreciable tumor induction in mouse skin by daily irradiation with high-power long-wavelength ultraviolet A (UVA).


OBJECTIVE
The aim of the present study was to examine the enhancing effects of UVA on changes in mouse skin mediated by the tumor promoter 12-o-tetradecanoylphorbol-13-acetate (TPA) by measurement of ornithine decarboxylase (ODC) activity and morphometric analysis. In addition, we examined the inhibitory effects of curcumin, a component of turmeric, on these changes.


METHODS
ODC activity in the epidermis of CD-1 mice was determined by the method of Russell and Snyder. Epidermal and dermal thickness, and the number of dermal infiltrating inflammatory cells were quantified using a computer-assisted image analyzer.


RESULTS
A combination of topical TPA application and UVA irradiation produced a greater increment of ODC activity at 4 h than TPA alone (p < 0.05). Histopathologically, TPA plus UVA tended to increase the dermal infiltrating inflammatory cells in contrast to TPA alone. Pretreatment of mice with curcumin significantly abrogated the TPA-induced changes in ODC activity and the dermal infiltrating inflammatory cells as well as the TPA plus UVA-mediated enhancement of these changes.


CONCLUSIONS
Our data indicate that UVA irradiation (18.72 J/cm2) significantly enhances ODC induction at an early stage (4-6 h) after topical application of TPA, and aggravates the dermatitis elicited by TPA. Pretreatment with curcumin significantly inhibits these enhancing effects.
Ishizaki
C
C
Department of Dermatology, School of Medicine, Showa University, Tokyo, Japan.
Oguro
T
T
Yoshida
T
T
Wen
C Q
CQ
Sueki
H
H
Iijima
M
M
D000818:Animals; D003474:Curcumin / Q000008:administration & dosage / Q000494:pharmacology*; D003872:Dermatitis / Q000201:enzymology / Q000209:etiology / Q000628:therapy*; D004195:Disease Models, Animal; D004347:Drug Interactions; D005260:Female; D051379:Mice; D008815:Mice, Inbred Strains; D009955:Ornithine Decarboxylase / Q000378:metabolism* / Q000528:radiation effects; D012867:Skin / Q000187:drug effects / Q000473:pathology* / Q000528:radiation effects; D013755:Tetradecanoylphorbol Acetate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D014466:Ultraviolet Rays
C032975:12-O-tetradeca-2,4,6,8-tetranoylphorbol-13-acetate; D009955:Ornithine Decarboxylase; D003474:Curcumin; D013755:Tetradecanoylphorbol Acetate