PUVA-induced erythema and changes in mechanoelectrical properties of skin. Inhibition by tocopherols

Abstract

Influence of antioxidants on two phototoxic effects of 8-methoxypsoralen (8-MOP) was studied: erythema and changes in mechanoelectrical properties of skin. alpha-Tocopherol and its analogs with shortened lateral hydrocarbon chains at C2-atoms of chromane groups (chromanols) were used as antioxidants. alpha-Tocopherol and its analogs inhibited both phototoxic effects of 8-MOP. Inhibition was observed only if antioxidants were present in skin during irradiation. When applied after irradiation these antioxidants produce no inhibitory effect. The antioxidant antierythemal action depends greatly on their concentration. The protective effects is maximal at antioxidant concentrations 2.5 . 10(-10) - 5 . 10(-9) mol . cm-2 of skin, at concentrations higher than 5 . 10(-9) mol . cm-2 the protective action is decreased. The protective effect of antioxidants depends on the irradiation dose.

Effect of alpha-tocopherol and di-butyl-hydroxytoluene (BHT) on UV-A-induced photobinding of 8-methoxypsoralen to Wistar rat epidermal biomacromolecules in vivo

“…This corresponds with the observation that AT-ac, without a free aromatic hydroxyl, did not protect against PUVA-induced erythema (Potapenko et al 1984). When in our experiments, rats were pre-treated with AT-ac on 4 consecutive days before 8-MOP was applied (experiment 2), a protective effect similar to that of AT with regard to protein and DNA/RNA binding was observed.…”

“…Thiols offered strong protection against in vivo photobinding of 8-MOP as well as CPZ (Van den Broeke, to be published). Potapenko et al (1984) demonstrated that protection against PUVA-induced erythema offered by tocopherol increased with the concentration of the antioxidant. However, at higher concentrations they observed that the protective effect diminished.…”

“…The foregoing has given rise to the idea that combining PUVA therapy with the topical or systemic administration of scavengers of reactive intermediates (antioxidants) would offer a way to suppress side-effects (Potapenko et al 1983(Potapenko et al , 1984Santamaria et al 1984Santamaria et al a, b, 1986Akhtyamov et al 1988;Akimov et al 1988). Indeed it has been found that antioxidants such as tocopherol and butylated hydroxy toluene (BHT) inhibited PUVA erythema (Pota- Akimov et al 1988) and that beta-carotene also prevented 8-MOP photocarcinogenesis in mice (Santamaria et al 1984 a).…”

Ultraviolet B-Induced DNA Damage in Human Epidermis Is Modified by the Antioxidants Ascorbic Acid and D-α-Tocopherol

“…In mice, topical vitamin E decreased UV-induced effects such as lipid peroxidation (Lopez-Torres et al, 1998), cutaneous photoaging (Bissett et al, 1990;Jurkiewicz et al, 1995), immunosuppression (Gensler and Magdaleno, 1991;Yuen and Halliday, 1997;Steenvoorden and Beijersbergen v Henegouven, 1999), and photocarcinogenesis (Bissett et al, 1990;Gensler and Magdaleno, 1991;Yuen and Halliday, 1997;Burke et al, 2000). Topical application of vitamin E to human skin has also been found to reduce UVB-and PUVA-induced skin erythema (Potapenko et al, 1980(Potapenko et al, , 1984.…”

Vitamins and photoaging: Do scientific data support their use?

“…Application of a-tocopherol before psoralen plus UVA therapy protected subjects against erythema in a dose-dependent fashion. 91 In addition, human skin pretreated with 5% vitamin E before UV exposure inhibited the normal up-regulation of human macrophage metalloelastase by 47%. 92 Human macrophage metalloelastase is involved in the degradation of elastin and is found primarily in chronically sunexposed areas of the skin, colocalizing with areas of solar elastosis.…”