Nonheme ferric and ferrous iron accumulation in macrophages of rats and cats

Perfusion-Turnbull and perfusion-Perls methods, which were recently developed in our laboratory, demonstrated that macrophages densely accumulated nonheme iron in both ferrous (Fe(II)) and ferric (Fe(III)) forms. In the spleen treated with bacterial lipopolysaccharide (LPS), which stimulates macrophages to produce cytotoxic nitric oxide (NO), the macrophages in the red pulp heavily loaded with nonheme Fe(II) and Fe(III) survived, while iron-free lymphocytes and less heavily iron-loaded macrophages in the white pulp and marginal zone were seriously affected. These findings suggested that dense nonheme iron shelter could protect macrophages from a NO-rich environment.