EFFECT OF UV RADIATION ON SURVIVAL OF NON-HAIRED MICE

Abstract— Patterns of mortality in a series of photocarcinogenesis experiments were examined. All experiments involved chronic irradiation of genetically non-haired mice with simulated sunlight from a Xe lamp. Experimental variables included genetic origin of the test animals, incident dose of radiation, and the spectral quality of the radiation. In 16 experiments involving 10 genetic origins of mice the following patterns were detected: (1) survival was inversely proportional to the delivered radiation dose; (2) within origins the life-shortening efficacy of radiation was closely correlated with its carcinogenic efficacy; (3) between genetic origins the carcinogenicity and lethality of a radiation dose were qualitatively correlated, but relative efficacy for the two effects varied; (4) altering the source spectrum by modifying the short-wave (UVB) cutoff produced similar changes in carcinogenicity and lethality, suggesting that UVB was a significant contributor to lethal efficacy; (5) nature and relative timing of the carcinogenic response were such that carcinogenesis was not likely to have caused the observed mortality. It is speculated that systemic effects, possibly immunologic or toxic, are produced by chronic UV irradiation, and that these apparently cumulative, dose-dependent effects result in premature death of non-haired mice.