Analysis of Action Spectra of UV-induced Mutation in Mouse Skin

DOI
  • IKEHATA Hironobu
    Graduate School of Medicine, Tohoku University
  • HIGASHI Shoichi
    National Institutes of Natural Sciences, National Institute for Basic Biology
  • WATANABE Masakatsu
    National Institutes of Natural Sciences, National Institute for Basic Biology School of Advanced Sciences, The Graduate University of Advanced Studies
  • HIEDA Kotaro
    Department of Life Science, Rikkyo University
  • ONO Tetsuya
    Graduate School of Medicine, Tohoku University

Bibliographic Information

Other Title
  • マウス皮膚における紫外線誘発突然変異の作用スペクトル解析

Search this article

Abstract

Wavelength-dependent biological effects of ultraviolet light (UV) for the human skin have been assessed mostly based on an action spectrum of human erythema that has been established in 1987 by the International Lighting Commission (CIE spectrum). However, it is questionable to apply the CIE spectrum for evaluation of the UV genotoxicity for skin, since there is little evidence to prove a causal relationship of the UV genotoxicity with erythema. To overcome this problem, we analyzed the mutagenic effects of each wavelength of UV directly in the skin, and established action spectra on UV genotoxicity for skin. To analyze in vivo mutations in the skin, mice with λ phage vector-based lacZ-transgenes were exposed to 260-364 nm monochromatic lights from a big monochromator, the Okazaki Large Spectrograph (OLS), and a 364-nm laser irradiator, both of which were available at the National Institute for Basic Biology (NIBB), Japan, and the transgene was analyzed for UV dose-dependent mutation induction kinetics in the epidermis and dermis. Based on those wavelength-dependent data, action spectra of the mutation induction in the skin were determined. Those action spectra in the epidermis and dermis were quite similar to each other and to the DNA action spectrum established by R. B. Setlow in 1974, which is an action spectrum of UV genotoxicity determined mostly based on bacterial studies, at wavelengths longer than 300 nm. Importantly, we found suppression of the mutation induction in the epidermis at high UV doses for almost all the wavelengths examined. In that epidermis-specific phenomenon of mutation induction suppression (MIS), the induced mutant frequency (MF) leveled off above a certain UV dose, and the minimum UV dose inducing MIS varied by the wavelength. The MIS action spectrum deduced from the minimum MIS doses was considerably similar to the erythema-based CIE spectrum in the wavelength range longer than 298 nm. Moreover, we also found that the epidermal leveled-off MFs varied by the wavelength, peaked around 310-320 nm and extremely repressed at both the shorter and the longer sides of wavelengths. This discovery indicates that the skin could tolerate UV genotoxicity at a wavelength range overlapping the UVB and UVA regions. (This study was carried out under the NIBB Cooperative Research Program for the Okazaki Large Spectrograph; 1-503, 2-503, 3-503, 4-507, 5-507, 6-511, 7-509, 8-501 and 9-501.)

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top