SPECTROCOLORIMETRIC ASSAY FOR THE 3 TYPES OF GASTROINTESTINAL MUCINS USING HISTOCHEMICAL STAINS

A method, transposed from the mucin histochemical stainings, was proposed to evaluate neutral, acidic and sulphated mucins by spectrocolorimetry. Stainings used were periodic acid/Schiff (PAS), Alcian blue (AB) pH 2.5, and Alcian blue (AB) pH 0.5. Mucin samples were extracted from mucosal scrapings, from intestinal contents of germ-free rats or from commercial pig gastric mucin. A mucin-enriched fraction was obtained and lyophilised and the protein content was determined. Each mucin type was spectrophotometrically analysed after staining and precipitation by slightly modified Carnoy fixative. The histochemical stainings used here, after modification by Carnoy fixative treatment, were, as shown by electrophoretic controls, specific for mucin types contained in these mucins without protein contaminant interference.