Concentration of iron and distribution of iron and transferrin after experimental iron overload in rat tissues in vivo: Study of the liver, the spleen, the central nervous system and other organs

The purpose of this study was to estimate the iron concentration in the liv er, spleen and brain of control rats and rats overloaded with iron and to d etermine the distribution of iron and of transferrin (TF). Iron was adminis tered to Wistar rats by food supplemented with 3% carbonyl iron for 3 month s, or intraperitoneally, or intraveneously as iron polymaltose for 4 months (total administered dose: 300 or 350 mg/rat, respectively). Iron concentra tion was estimated by atomic absorption spectrophotometry and iron- and TF- distribution histochemically and immunohistochemically, respectively. In co ntrol rats the organ with the highest iron content was the spleen, followed by the liver and brain. After iron loading the increase of iron in the liv er was greater than that of the spleen; iron concentration in the brain did not change significantly. Distribution of iron in the liver was in Kupffer cells throughout the lobule and in hepatocytes at its periphery. No differ ence in the number of positive cells or staining intensity for TF was obser ved between control rats and iron overloaded animals in the liver or centra l nervous system (CNS); the spleen was negative for TF Distribution of TF i n the liver showed a centrilobular localisation in hepatocytes. TF reaction in the brain occurred in oligodendrocytes, vessel walls, choroid plexus ep ithelial cells and some neurons. In conclusion, experimental iron overload in rats leads to iron uptake mainly by reticuloendothelial (RE) cells and h epatocytes, indicating that hepatocytes are of particular importance for ir on metabolism. Iron uptake by the brain was not significant, probably becau se the brain is protected against iron overload. Iron overload did not infl uence location and quantity of TF in the liver and CNS, whereas the visuali sation of iron and TF did not coincide. This indicates that TF may have oth er functions beyond iron transport.