Identification of a mucin layerin the urinary bladder

Abstract

Objectives. The specific goal of this study was to establish a simple histochemicaltechnique by which the glycosaminoglycan (GAG) lining in the rabbit bladder can be routinely identified. Methods. Rabbit bladder tissues were fixed in zinc formal, 10% neutral buffered formalin (NBF), 20% NBF, 40% NBF, 2% calcium acetate in 10% NBF, 2% sodium acetate in 10% NBF, 1 % cetylpyridinium chloride in 10% NBF, 80% alcohol, histochoice, and 2.5% glutaraldehyde in 0.1 M cacodylate buffer. The following histochemical staining was used: mucicarmine/metanil yellow, colloidal iron, deamination followed by colloidal iron, periodic acid-Schiff, saponification followed by colloidal iron, Alcian blue (AB) at variable pH values, combined aldehyde-fuchsin/AB, performic acid/AB, AB/Alcian yellow, high temperature (60°C) methylation/saponification/AB, and AB/nuclear fast red at pH 5.8 with critical electrolyte concentrations with or without deamination. Results. AB with sodium acetate buffer at pH 5.8 containing 0.6 M or 0.8 M magnesium chloride (MgCl 2) showed a well-defined thin GAG lining on the surface of the urothelium, whereas histochemical staining used by previous investigators showed only patchy distribution. There was no observable difference due to the gender, fixative, or region of the bladder from which the tissue was obtained. Conclusions. A very thin lining of GAG exists in the rabbit bladder which can be localized by AB in sodium acetate buffer at pH 5.8 containing 0.6 M or 0.8 M MgC1 2 but not by conventional histochemical techniques. This method now can be applied to answer many questions regarding urothelial function.