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 μg for peroxidated squalene and over 20 μg 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.
|Number of pages||6|
|Journal||Photodermatology Photoimmunology and Photomedicine|
|Publication status||Published - 1991|
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