Effects of prolonged iron loading in the rat using both parenteral and dietary routes

Female Porton rats have been treated with either parenteral iron (intraperitoneal red cells) or dietary iron (carbonyl iron) for up to 12 months or 22 months respectively. In the parenteral iron loaded animals, the liver iron concentration rose from approximately 2 mg g-1 dry wt at 2 months to 21 mg g-1 dry wt at 12 months, while for the dietary iron loaded animals, this value rose from 14 to 48 mg g-1 dry wt at 12 months to over 60 mg g-1 dry wt after 22 months. In contrast, splenic iron concentrations rose more in the parenterally loaded animals (up to 66 mg g-1 dry wt after 12 months) than in the dietary loaded animals (approx. 34 mg g-1 dry wt after 24 months). This study yielded hepatic iron concentrations comparable to those seen in human thalassaemia patients with comparative low hepatotoxicity. Splenic iron concentrations in the parenteral iron loaded group generally exceeded those reported in thalassaemia. Iron concentrations derived from computer assisted morphometry of liver iron deposits correlated well (r = 0.88, p < 0.001) with chemical analysis data. The fraction of iron in the non-parenchymal cells correlated positively with the duration of iron loading (r = 0.86, p < 0.001).