Studies on the rat liver following iron overload. A morphometrical investigation of parenchymal and Kupffer cells.

The lysosomal vacuome of parenchymal and Kupffer cells of the liver has been shown to be involved in the storage of iron during iron overload. In order to morphologically quantify alterations in the course of this process a morphometrical analysis of liver cells and subcellular organelles (lysosomes, autophagic vacuoles, and mitochondria) has been performed. The results showed that the Kupffer cells increased in volume density (Vv) as the cells became loaded with iron whereas other cell compartments were unaffected. The volume density of Kupffer cell lysosomes was slightly increased when expressed on "per cell" basis. However, since the volume of the Kupffer cells increased simultaneously, the total volume of the lysosomes in these cells was increased more than 100%. Parenchymal cell lysosomal Vv increased approximately 100% following iron loading. This increase in parenchymal cell lysosomes was most pronounced in periportal cells while centrilobular cells were less affected in this respect. Both Kupffer cell Vv and lysosomal Vv in Kupffer and parenchymal cells were decreased when enhanced mobilization of iron was induced by bleeding. The results agree with the notion that the increase in Vv of the lysosomal vacuome during iron overload is due to the accumulation of iron binding storage proteins.