Direct comparison of DNA damage, isomerization of urocanic acid and edema in the mouse produced by three commonly used artificial UV light sources

Exposure to sunlight can result in a number of harmful effects, including s unburn, erythema, premature aging of the skin, immune suppression and skin cancer. Studies designed to understand the underlying mechanisms often depe nd upon the use of artificial sources of UV radiation. Unfortunately, concl usions from different laboratories using different lamps often conflict, an d it is entirely possible that the different spectra of sunlights used in e ach may be a source of conflict. To minimize confounding variables, we empl oyed two of the more commonly used UV light sources, fluorescent sunlamps, such as the FS-40 and Kodacel-filtered FS-40 sunlamps, and a xenon are sola r simulator and compared, in one series of standardized experiments, the ef fects of each light source on DNA damage, urocanic acid isomerization and e dema formation. The dose-response curves, calculated by linear regression o r curve fitting were compared, The data indicate that DNA damage and urocan ic acid isomerization were more sensitive to shorter wavelengths of UV than longer wavelengths, and the biological endpoint of edema most closely corr elated with the induction of DNA damage. The results emphasize the dominanc e of shorter wavelengths within the UV spectrum in damaging biological tiss ues, even when the solar simulator, which contains significant amounts of U VA, was used and demonstrate that each light source has a characteristic pa ttern of induction of biochemical and biological endpoints.