A method to assess 59Fe in residual tissue blood content in mice and its use to correct 59Fe-distribution kinetics accordingly

Background: Dysregulation of body iron-distribution may induce oxidative damage. To investigate the molecular mechanisms of iron homeostasis, corresponding essential genes are manipulated by many working groups. This asks for a simple method to pursue the resulting impact on body iron-distribution in mice. Aim: To develop a method for the assessment of Fe-59 in residual tissue blood content and to correct this influence in Fe-59 body distribution studies. Methods: Iron status in male adult C57BL6 mice was adjusted by feeding diets with different iron content. Fractional contribution of organs to total body weight was determined after dissection. Fe-59-labelled blood was injected in recipient mice to estimate total blood volume and residual blood content in all organs and tissues. The main experiment used these data to correct total Fe-59 tissue content at six intervals after Fe-59 injection (12h-28 days). Results and discussion: The sum of Fe-59 in all organs was the same as determined in each mouse before dissection. Fe-59 in whole blood remained constant from the 4th day after injection on, and was highest in iron-deficiency. As in other species, residual blood content was highest in spleen and lungs. Nevertheless, Fe-59 in the iron-deficient spleen decreased to zero and intestinal Fe-59-content also decreased significantly over time after correction for Fe-59 in residual blood. These findings suggest correct assessment of compartment sizes and Fe-59 in residual blood in each organ. Conclusions: Differences in Fe-59-distribution between iron status reflected changes in the expression of proteins of iron-transport and its regulation correctly. Thus, the method seems suitable to analyse body iron-distribution in consequence to genetic manipulations of murine iron homeostasis which is a prerequisite to assess possible toxicological consequences of iron supplementation. (C) 2007 Elsevier Ireland Ltd. All rights reserved.