Hisamasa Kodaira1, Kazuhiko Ishihara2, Kyoko Hotta3,
Masatoyo Kagoshima1, Hideyo Shimada4 and Kunio Ishii1
1Department of Molecular Pharmacology and 4Division
of Pathophysiology, School of Pharmaceutical Sciences, Kitasato University,
Tokyo 108 - 8641, Japan
Departments of 2Chemistry and 3Biochemistry, School
of Medicine, Kitasato University, Sagamihara 228 - 8555, Japan
Abstract: The sialylated mucus components of the normal gastric
mucosa and mucous gel layer of rats were studied by using various histochemical
staining methods including Maackia amurensis II (MAL-II) and Sambucus
nigra (SNA) lectins, alcian blue (AB) pH 2.5 - periodic acid Schiff
(PAS) and high iron diamine (HID) - AB pH 2.5. The acidic and neutral mucins
characterized by the AB-PAS staining were abundantly present in the mucous
gel layer as well as in the gastric mucosa. The sialomucin characterized
by HID-AB was barely found in either the mucous gel layer or the mucosa.
The sialomucin positive to MAL-II and SNA, which react with the N-acetyl
neuraminic acid residue linked to galactose via an α-linkage, was moderately
detected only in the mucous gel layer, but not in the entire mucosal layer.
Furthermore, in animals given surgery to form an esophageal fistula through
which saliva was excluded or in animals subjected to salivectomy, the mucous
gel layer stained with MAL-II and SNA lectins was markedly decreased. These
results indicate that a part of the sialomucin containing-mucous gel layer
covering normal rat gastric mucosa originates from the saliva and that MAL-II
and SNA lectins are useful for detecting this specific sialomucin.
Keywords: Sialomucin, Saliva, Gastric mucus gel, Lectin