title: Evaluation of ultraviolet-A protection by sunscreen agents using a mouse model of contact photoallergy.
abstract: This study was conducted to investigate in vivo evaluation of protectiveness by sunscreens in the UVA range using a mouse model of contact photoallergy (CPS) to 3,3',4',5-tetrachlorosalicylanilide (TCSA). Mice were sensitized with TCSA painting plus UVA irradiation (TCSA/UVA) on the abdomen and, 5 days later, challenged with TCSA/UVA on the earlobe. Each of four sunscreen agents, benzophenone-3, Parsol 1789, p-aminobenzoic acid, and 2-ethyl-hexyl-p-methoxycinnamate, was applied to the earlobes before irradiation. Their protective efficacy was evaluated in the degree of inhibition of both ear swelling responses and TCSA-epidermal cell photoadduct formation. Two UVA-absorbing sunscreens, benzophenone-3 and Parsol 1789, dramatically inhibited the ear swelling response, while the two UVB-absorbers exhibited a much less suppressive effect. The UVA-absorbing agents functioned via inhibiting the formation of TCSA-epidermal cell photoadducts. This method is thought to be useful for in vivo estimation of UVA protection provided by sunscreens against the exquisite sensitivity involved in photoallergy.
authors.affiliation: Department of Dermatology, Hamamatsu University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura
authors.forename: H
authors.initials: H
authors.lastname: Yagi
authors.forename: H
authors.initials: H
authors.lastname: Ihda
authors.forename: M
authors.initials: M
authors.lastname: Takigawa
mesh_terms: D000818:Animals; D003877:Dermatitis, Contact / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D017454:Dermatitis, Photoallergic / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D004817:Epidermis / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D012458:Salicylanilides / Q000276:immunology*; D013473:Sunscreening Agents / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D012458:Salicylanilides; D013473:Sunscreening Agents; C003390:3,3',4',5-tetrachlorosalicylanilide