Abstract
To understand health effects of low-dose and low-dose-rate radiation, many analyses on the changes at molecular levels have so far been conducted. The analyses of protein expression in connection with biological functions provided useful information for the evaluation of the health effects. We have reported changes of protein expression in the liver from mice irradiated at low-dose rates and for a long period. On the other hand, comparative studies between chronic and acute irradiation offer critical information for understanding of molecular mechanisms underlying a dose-rate effect. In the present work, changes in protein expression in the liver of mice irradiated with 4Gy (a sub-lethal dose) or 8Gy (a lethal dose) were investigated. In addition, the alteration of protein expression was investigated in mice irradiated with 8Gy delivered in a protracted period of 400 days. Since long-term exposure with a total dose of 8Gy is not a lethal dose for the mouse, the time-dependent change in protein expression after the end of irradiation was analyzed. Comparative analyses of the protein expression by the two-dimensional gel electrophoresis and the comprehensive analyses of changes in protein expression using antibody arrays were performed. We will discuss the responses of a living body to radiation and its defense systems with references to changes in protein expression based on the results of comparative analyses between sub-lethal and lethal doses as well as between acute and chronic irradiation.
