Ultrastructural staining of thin sections with iron hematoxylin.

Abstract

Verhoeff's iron hematoxylin (VIH) applied to epoxy thin sections provides ultrastructural staining of selected sites including elastic fibers, ribosomes, heterochromatin in nuclei of somatic cells, chromatin clumps in germ cells and the nucleolonema and ovoid body of the nucleolus of primary spermatocytes. Granules in rat parotid acinar cells show several staining patterns not otherwise easily recognized. Mucous droplets or granules of goblet or Paneth cells of the ileum stain. Staining of defined polymers in epoxy thin sections indicates that VIH reacts with polycations and polyanions. Ethanolic hematoxylin alone at pH 1.3 imparts electron opacity to heterochromatin, ribosomes, parotid granules and elastica but yields no staining for light microscopy. A hematoxylin-FeCl3, solution stains mucus of goblet and Paneth cells. The latter staining, which requires FeCl3 in the solution, can be eliminated by saturating the solution with NaCl and, accordingly, depends on ionic binding. Staining of elastic fibers and parotid acinar granules depends on hydrogen bonding, since saturation of the VIH or hematoxylin solution with urea blocks the ultrastructural staining. Urea does not, however, alter the staining of nuclear structures or ribosomes.