A biochemical, histochemical, and electron microscopic study on the effects of iron-loading on the hearts of mice

Acute iron poisoning and chronic iron overload are well-known causes of myo cardial failure. Although the exact mechanism is not known, excess iron-cat alyzed free radical generation is conjectured to play a role in damaging th e myocardium and altering cardiac function. We report here on the effects o f acute and chronic iron-loading on the total iron concentration, glutathio ne peroxidase activity, and cytotoxic aldehyde production in the heart of a murine model (n = 35). Light microscopic examination for the presence of f errous and ferric iron was undertaken following histochemical staining for these species. In addition, examination of representative samples by transm ission electron microscopy was performed. Our findings show that iron-loadi ng can result in significant increases in total iron concentrations, altera tions to glutathione peroxidase activity, and increases in cytoxic aldehyde concentrations in the hearts of mice. Furthermore, we observe that iron-lo ading can significantly alter and damage various cellular constituents (e.g ., mitochondria, lysosomes, sarcoplasmic reticulum) and this may have beari ng on the mechanism of iron-induced heart failure. (C) 1999 by Elsevier Sci ence Inc.