Prevention of photocarcinogenesis by dietary vitamin E.
Ultraviolet B (UV-B) irradiation of C3H/HeN mice induces skin cancer. In this study, the ability of dietary d-alpha-tocopheryl acetate to reduce photocarcinogenesis was tested in this murine model. Skin cancers developed in 67.5% of UV-B-irradiated mice by 31 weeks after the first UV exposure. Supplementation with 100 or 200 IU of d-alpha-tocopheryl acetate per kilogram of diet led to a reduction of the incidence to 46% and 19%, respectively. The latter value was significantly different from that found in mice fed the basal diet (p = 0.039, one-sided P value by log-rank test). Skin levels of alpha-tocopherol varied with the dietary dose of d-alpha-tocopheryl acetate. No toxicity was evident in unirradiated mice fed the vitamin E-supplemented diet, but 40% of the UV-B-irradiated mice fed 200 IU of vitamin E per kilogram of diet died by 31 weeks after the first UV-B treatment. Decreased relative spleen weight was observed in the UV-B-irradiated mice fed the vitamin E-supplemented diet. In summary, oral d-alpha-tocopheryl acetate prevented photocarcinogenesis, but at doses that were toxic to inbred C3H/HeN mice after exposure to 8.6 x 10(5) J/m2 of UV-B irradiation.
Department of Radiation Oncology, University of Arizona, Tucson 85724.
K E
KE
Gerrish
H L
HL
Gensler
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D004032:Diet; D005260:Female; D051379:Mice; D008809:Mice, Inbred C3H; D012867:Skin / Q000737:chemistry; D012878:Skin Neoplasms / Q000517:prevention & control*; D024505:Tocopherols; D014466:Ultraviolet Rays / Q000009:adverse effects*; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000032:analysis / Q000494:pharmacology / Q000633:toxicity; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D000975:Antioxidants; D014810:Vitamin E; D024502:alpha-Tocopherol; D024505:Tocopherols