The histochemical differences of intestinal gland epithelia in the rat colon with special reference to their glycoconjugates.

Abstract

The histochemical feature of epithelial mucins of the rat proximal colon differed from that of the distals. The regional differences were elucidated by various mucin-staining methods, such as periodic acid-Schiff (PAS), Alcian blue (pH 2.5) -PAS (AB-PAS), high iron diamine (HID) -AB (pH 2.5), and O-acylated sialic acid specific staining: periodic acid-thionin Schiff (PATS) /-periodate-borohydride technique (PBT) /potassium hydroxide (KOH) /periodic acid-Schiff (PAS) technique for light microscopy, periodic acid (PA) -thiocarbo-hydrazide (TCH) -silver proteinate (SP) staining, O-acylated sialic acid specific staining and dialyzed iron staining for electron microscopy. The distribution of sugar residues of the glycoproteins in the colonic epithelial mucin was also examined by lectin-horseradish peroxidase (HRP) staining method. Goblet cells at the upper half of the crypt in the proximal colon contained mainly neutral mucin and at the lower half, their mucin showed alcianophilic nature predominantly. Sulfomucin secreting-cells were distributing only at the near luminal surface of the proximal colon and all through the crypt of the distal colon. Some goblet cells, columnar cells and vacuolated cells contained O-acylated sialoglycoconjugates. The lectin staining-patterns differed from each other. Some lectins stained the upper half goblet cell-mucin only or the lower half goblet cell-mucin, while other lectins stained goblet cells of the whole crypt. It seemed that the histochemical staining features changed at the branching site of the crypt in the proximal colon. On the other hand, such a transitional zone was obscure in the distal colon.