Iron deficiency in growing male rats: a cause of development of cardiomyopathy

Weanling male rats were fed a purified iron-adequate, a purified iron-deficient or a commercial diet for 12 weeks. At that time the rats were sacrificed, their hearts and livers were excised, and blood samples were taken. Heart and liver weights were recorded; organ tissue and serum samples were analyzed for Zn, Cu and Fe. Hemoglobin and hematocrit values were also obtained. The iron-deficient rats grew much more slowly than controls on the iron-adequate or commercial diets. The iron-deficient rats were severely anemic and had enlarged hearts (cardiomegaly). A histopathologic examination of the hearts of all animals showed that each heart of the iron-deficient rats had lesions characteristic of cardiomyopathy by dilatation, whereas none of the hearts of the iron-adequate group or the chow controls showed any lesions at all. The iron-deficient animals had only about 25% of the hepatic iron found in the iron-adequate animals but about 5 times the hepatic copper of the latter group or the chow controls. Heart iron of the iron-deficient group was 27% of the concentration found in hearts of the iron-adequate rats; heart copper was similar in all groups. Animals on the commercial stock diet accumulated significantly more iron in their hearts than did those on the purified iron-adequate diet but not in the livers. There was also a direct correlation of heart iron or heart zinc with log concentrations of dietary iron and consequently a direct correlation between heart iron and zinc concentrations.