RESUMO
Mouse skin was exposed to UVA radiation (320-400 nm). The in vivo chemiluminescence of the skin was measured after irradiation. Chemiluminescence showed a maximum 13-fold increase (control emission, 10 +/- 1 cps cm-2) after 45-60 min of exposure to UVA, with no further increase with 60 min additional exposure. Spectral analysis of the emitted chemiluminescence showed that the principal species emitted in the 400-500 nm range. Topical application with alpha-tocopherol (10% v/w) and beta-carotene (1 mM) greatly reduced the UVA-induced skin chemiluminescence. Thiobarbituric acid reactive substance (TBARS) levels were increased by 130% in skin homogenates after 2 h of exposure to UVA (control value, 77 +/- 14 nmol malonaldehyde equivalents (g tissue)-1). The activities of antioxidant enzymes in skin homogenates were decreased after 2 h of irradiation: the superoxide dismutase (SOD) activity (control value, 181 +/- 10 U SOD (g tissue)-1) was decreased by 40% and the catalase activity (control value, 1.34 +/- 0.14 pmol (g tissue)-1) was decreased by 45%. In vivo chemiluminescence appears to be a suitable method for following the kinetics of the oxidative stress processes and for testing the effect of topical application with antioxidant and photoprotective agents.
Assuntos
Estresse Oxidativo , Pele/efeitos da radiação , Raios Ultravioleta , Administração Tópica , Animais , Catalase/metabolismo , Feminino , Medições Luminescentes , Camundongos , Pele/efeitos dos fármacos , Pele/metabolismo , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Vitamina E/administração & dosagem , Vitamina E/farmacologia , beta Caroteno/administração & dosagem , beta Caroteno/farmacologiaRESUMO
BACKGROUND: Actinic prurigo has a high prevalence in women of child-bearing age. Its treatment has been, among others, with thalidomide. To avoid the deleterious effects of this drug on the embryo, therapeutic alternatives have been sought. Among these, tetracycline and vitamin E have been investigated as to their influence on the symptoms of actinic prurigo. Both these drugs affect superoxide radicals that are thought to be involved in the pathogenesis of actinic prurigo. MATERIALS AND METHODS: Patients (Chimila Indians with a high prevalence of actinic prurigo) received either (a) tetracycline, 500 mg three times daily, for 6 months, or (b) vitamin E, 100 IU daily, for 6 months. The patients were seen once monthly. There were eight patients in each group. RESULTS: Both drugs used were effective. Pruritus was remarkably improved by either treatment. None of the side effects were severe enough to lead to interruption of treatment, but the observation period posttreatment was relatively short, 4 months for tetracycline and 2 months for vitamin E. The improvement occurred in spite of the continuation of extensive exposure to the sun. CONCLUSIONS: Tetracycline and vitamin E are efficacious in relieving the pruritus of actinic prurigo. Preliminary trials of a combination treatment with these two drugs is a new avenue which has shown in preliminary trials to yield synergistic effects which might allow the dosage of tetracycline to be reduced.
Assuntos
Transtornos de Fotossensibilidade/tratamento farmacológico , Prurigo/tratamento farmacológico , Antibacterianos/efeitos adversos , Antibacterianos/uso terapêutico , Queilite/tratamento farmacológico , Colômbia , Feminino , Humanos , Indígenas Sul-Americanos , Transtornos de Fotossensibilidade/etnologia , Prurigo/etnologia , Prurigo/etiologia , Tetraciclina/efeitos adversos , Tetraciclina/uso terapêutico , Vitamina E/efeitos adversos , Vitamina E/uso terapêuticoRESUMO
The Chimila, a Colombian Amerindian group that lives at a low altitude, have a high incidence of actinic prurigo. We present the human lymphocyte antigen (HLA) findings of 43 Chimilas with the disease and of 62 control subjects and show an association of actinic prurigo with the Cw4 antigen.