CELLULAR AND SUBCELLULAR LOCALIZATIONS OF NONHEME FERRIC AND FERROUS IRON IN THE RAT BRAIN: A LIGHT AND ELECTRON MICROSCOPIC STUDY BY THE PERFUSION-PERLS AND -TURNBULL METHODS

摘要

Abstract Iron is essential for a variety of cellular functions. However iron,especially ferrous form,has the potential for catalyzing the Fenton reaction to generate highly cytotoxic hydroxyl radicals. Therefore the amount of iron in the brain is strictly controlled. In this study we focused on the cellular and subcellular localizations of nonheme ferric (Fe(III)) and ferrous (Fe(II)) iron in the adult female rat brain by light and electron microscopic histochemistry. Although Fe(II) deposition was much less dominant than Fe(III),the brain contained iron in both forms. Among the cellular elements of the brain,oligodendrocytes were numerically most prominent and heavily iron-storing cells. Pericapillary astrocytes and sporadic microglial cells also showed dense iron accumulation. Large neurons involved in the motor system were relatively strongly iron-positive. Subcellularly,Fe(III) and Fe(II) were mainly localized in lysosomes,and occasionally in the cytosol and mitochondria. Fe (II)-specific deposit was shown on the luminal membrane of endothelium. With advancing age,both Fe(III) and Fe(II) became distributed more extensively,and accumulated more numerously into oligodendrocytes.