Am. J. Respir. Crit. Care Med.,
Volume 164, Number 6, September 2001, 1077-1082
Differential Properties of Mucous Glycoproteins in Rat
Nasal Epithelium
A Comparison between Allergic Inflammation and
Lipopolysaccharide Stimulation
TAKESHI
SHIMIZU,
HITOMI
HIRANO,
SHINO
SHIMIZU,
CHIKAKO
KISHIOKA,
YASUO
SAKAKURA,
and
YUICHI
MAJIMA
Department of Otorhinolaryngology, Mie University School of Medicine, Mie 514, Japan
To examine the differential properties of mucous glycoproteins,
we produced hypertrophic and metaplastic changes in goblet cells
of rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats, and by intranasal lipopolysaccharide (LPS) instillation. The epithelial mucosubstance was quantitatively examined by alcian blue-periodic acid-Schiff (AB-PAS) and lectin histochemistry. The newly produced mucin after OVA challenge or LPS instillation contained a high amount of sulfomucin and a low amount of neutral glycoprotein: LPS-induced mucin contained
more sulfomucin (70.1% of total) and less neutral glycoprotein
(8.6%) than OVA-induced mucin (sulfomucin, 33.6%; neutral glycoprotein, 41.8%; p < 0.01). Four of the lectins stained some of
the mucosubstance, indicating the presence of galactose-N-acetylgalactosamine, 
2,3- and 2,6-linked sialic acid-galactose, and fucose residues. After LPS instillation, the reactivity was higher for
galactose-N-acetylgalactosamine (64.8% of total) and 2,3-linked
sialic acid-galactose (75.8%) than after saline instillation (3.5 and
19.1%, respectively) or OVA challenge (5.8 and 32.3%; p < 0.05).
OVA challenge did not induce the alteration of terminal sugar residues. A 2-fold increase in mucin mRNA (rat Muc5ac) expression
was induced after LPS instillation or OVA challenge, compared
with animals treated with saline instillation (p < 0.05). These results indicate that mucin mRNA expression (for peptide backbone)
increases similarly after LPS instillation or OVA challenge; however, carbohydrate compositions of newly produced mucin are different between the two groups.
Keywords: allergic inflammation; goblet cell; lectin; lipopolysaccharide; mucus
