Topical Application of a Novel, Water-soluble γ-Tocopherol Derivative Prevents UV-induced Skin Damage in Mice

• Published in: Photochemistry and photobiology Vol. 81; no. 4; pp. 908 - 913
• Main Authors: Yasuoka, Shingo, Takata, Jiro, Karube, Yoshiharu, Katoh, Eiko, Tsuzuki, Toshi, Kizu, Junko, Tsuchiya, Masao, Kobayashi, Shizuko
• Format: Journal Article
• Language: English
• Published: United States 01.07.2005
• Subjects: Administration, Topical; Animals; Female; gamma-Tocopherol - pharmacology; Mice; Mice, Hairless; Radionuclide Imaging; Research s; Skin - radiation effects; Skin Diseases - diagnostic imaging; Skin Diseases - prevention & control; Ultraviolet Rays
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1562/2004-09-02-RA-300R2.1

We investigated whether the topical application of a novel, water-soluble γ-tocopherol (γ-Toc) derivative, γ-tocopherol-N,N-dimethylglycinate hydrochloride (γ-TDMG), could protect against UV-induced skin damage in hairless mice. Topical pre- or post-application of a 5% (93 mM) γ-TDMG solution in water/propylene glycol/ethanol (2:1:2) significantly prevented sunburn cell formation, lipid peroxidation and edema/inflammation that were induced by exposure to a single dose of UV irradiation of 5 kJ/m2 (290–380 nm, maximum 312 nm). This effect was greater than that seen with two α-Toc derivatives, α-tocopherol acetate (α-TA) and α-tocopherol-N,N-dimethylglycinate (α-TDMG). When a 5% solution of γ-TDMG was applied to mouse skin for 1 h, cutaneous γ-Toc increased by 25-fold after 24 h; levels of cutaneous α-Toc increased by only two- and eight-fold in α-TDMG and α-TA treated skins, respectively. These findings indicated that γ-TDMG immediately converted to γ-Toc in the skin and suggest that ability of γ-TDMG to protect the skin from the damaging effects of irradiation was due to its conversion to γ-Toc. When a 5% solution of γ-Toc was applied to mouse skin for 1 h, cutaneous γ-Toc rapidly increased by 25-fold, but fell to baseline levels by 24 h. In contrast, the concentration of γ-Toc in skin that was treated with γ-TDMG similarly increased, but these high levels were maintained after 24 h. These results suggest that γ-TDMG may be a more effective source of γ-Toc in skin. Thus, the topical application of γ-TDMG may be efficacious for the prevention of UV-B-induced skin damage.