Squalene peroxides may contribute to ultraviolet light-induced immunological effects.
Ultraviolet (UV) irradiation is capable of producing a dose-dependent decomposition of skin surface lipids and particularly of squalene, with the concomitant generation of active lipoperoxides. The biological effects of UV-peroxidated squalene were tested, compared with those produced by synthetic lipoperoxides (cumene hydroperoxide), on some immunological parameters in vivo modified by UVB irradiation. Application of UV-peroxidated squalene as well as cumene hydroperoxide significantly inhibited the induction of contact hypersensitivity to dinitrofluorobenzene in mice, which was associated with a decrease in the number of ATPase positive cells. The effect was dose-dependent (over 40 micrograms for peroxidated squalene and over 20 micrograms for cumene) and relevant after 2 d of treatment. Down-regulation towards the applied hapten was demonstrated. The results indicate that UV-induced lipoperoxides of squalene are capable of inhibiting the induction of contact hypersensitivity in mice and suggest that, among the other photoproducts generated in humans, squalene peroxides may play a role as biochemical messengers of the biological effects of UV irradiation of the skin.
Picardo
M
M
Istituto Dermatologico San Gallicano, Rome, Italy.
Zompetta
C
C
De Luca
C
C
Amantea
A
A
Faggioni
A
A
Nazzaro-Porro
M
M
Passi
S
S
D000818:Animals; D001555:Benzene Derivatives / Q000494:pharmacology; D003877:Dermatitis, Contact / Q000209:etiology / Q000276:immunology*; D004307:Dose-Response Relationship, Radiation; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D012867:Skin / Q000276:immunology* / Q000473:pathology / Q000528:radiation effects; D013185:Squalene / Q000031:analogs & derivatives* / Q000494:pharmacology; D014466:Ultraviolet Rays / Q000009:adverse effects*
C002821:2,3-oxidosqualene; D001555:Benzene Derivatives; D013185:Squalene; C007164:cumene hydroperoxide