Assessment of iron absorption in mice by ICP-MS measurements of 57Fe levels

BACKGROUND: The study of iron metabolism is essential in nutritional sciences as iron deficiency is one of the most common nutritional deficiencies in humans and represents a serious health problem worldwide. The mouse is utilized as a unique and powerful model for the identification and characterization of genes involved in iron metabolism and for studying the pathogenesis of iron disorders. Thus, sophisticated and sensitive techniques have been developed to study iron metabolism in this animal model. In particular, iron absorption has been studied in mice by using the radioisotopes (55)Fe and (59)Fe in tied-off or dissected and everted duodenal segments. Nevertheless, several drawbacks discourage the extended use of these approaches. METHODS AND RESULTS: Here, we report the use of the stable isotope (57)Fe to measure iron absorption in mice. We show that after oral administration of (57)Fe-containing solutions, it is possible to measure both duodenal iron retention and duodenal iron transfer to specific organs, using inductively coupled plasma mass spectrometry (ICP-MS). As (57)Fe is administered orally, no surgical operation is needed before the end of the experiment, thus allowing the measurement of iron absorption under physiologic conditions. Moreover, the use of ICP-MS for (57)Fe detection ensures high sensitivity and provides quantitative data. Finally, the use of a stable isotope enables the measurement of both iron absorption and histologic and/or biochemical analyses in the same animal. CONCLUSIONS: The use of (57)Fe to measure iron absorption in mice, therefore, represents an alternative to radioisotope-based methods, providing a new tool to extend our knowledge on the mechanism of iron absorption.