Iron Distribution in Dietary‐Induced Obese Mice Tissues

Iron homeostasis is required to maintain normal physiological processes such as oxygen delivery, DNA synthesis, and enzymatic reactions. An overall disturbance of iron homeostasis, e.g. systemic iron deficiency, was reported in obese subjects. The objective of this study was to examine tissue iron distribution in the dietary‐induced obese mice. Thirty male C57BL/6J mice were randomly assigned into six dietary treatment groups with various levels of iron (control, high and low) and fat (control and high) for 24 weeks. At the end of 24 weeks, tissues including liver, brain, heart, spleen and kidney were harvested and embedded in paraffin. Tissues were then processed and stained for iron using the Prussian blue reaction. Images were recorded using the Motic BA310 compound light microscope at 1000x magnification. Results showed that brain and spleen were the most responsive organs to dietary fat and iron treatments. In both brain and spleen, iron deposits were observed in high iron groups at both control and high fat levels. In the brain, iron deposits were surprisingly observed in mice treated with high fat low iron diet, indicating the vulnerability of brain to possible iron‐induced oxidative stress. To further evaluate overall brain iron disturbance by high fat diet, the expression of iron‐related proteins (storage, transport, and export proteins) and oxidative stress markers will be measured.