Correlation of gastric mucosal damage with sialic acid profile in rats: effect of hydrochloric acid, pepsin and hypertonic saline

Abstract

Sialic acids occupy terminal positions on gastric mucus glycoprotein where they contribute to the high viscosity of mucin. Desialylation of mucus may lead to degradation of the mucus and eventually to the breakdown of the gastric mucus barrier. The effect of a variety of damaging agents (0.1 M HCl, 2 mg ml(-1) pepsin and 2 M NaCl) on sialic acid profile was determined in pylorus-ligated rats. The relationship between sialic acid, galactose, pyruvate and the extent of gastric mucosal damage were studied. Instillation of pepsin significantly increased total sialic acid, galactose and macroscopic mucosal lesions in the stomach. Instillation of 0.1 M HCl reduced the total sialic acid but this decrease was not significant. Acidity led to a significant increase in the amount of free sialic acid in the gastric instillates and the macroscopic lesions induced by acid was not significantly different from the control animals (0.15 M NaCl). 2 M NaCl induced the macroscopic lesions in the stomach and also free sialic acid in the instillates. Pepsin potentiates the action of 2 M NaCl. In all the agents examined with the exception of acid, it was observed that an increase in free sialic acid and galactose was accompanied by gastric mucosal erosion and elevation of pyruvate concentration. It is concluded that gastric acidity alone is not inherently damaging and that resistance of gastric mucosa to destructive agents may be dependent on the integrity of the sialic acids.

Echinostoma caproni (Trematoda): differential in vivo mucin expression and glycosylation in high‐ and low‐compatible hosts

“…This would imply that E. caproni may change the rheological properties of the mucus barrier at early infection in rats. Sialic acids occupying terminal positions on mucus glycoproteins have been seen to elevate the viscosity of mucus and desylation of mucins may lead to degradation of the mucus matrix . Mucins with abundant sialic acid residues may trap the intestinal worms and induce their expulsion .…”

Vulnerable Sites and Changes in Mucin in the Rat Small Intestine After Non-steroidal Anti-inflammatory Drugs Administration

“…Sialic acid usually occupies the terminal position of the oligosaccharide of the glycoconjugate, and these terminal residues have a significant influence on mucus charge, mucus rheology, and mucus degradation. The mucus charge elicited by the presence of sialic acid residues is thought to contribute to the high viscosity of mucin, leading to enhanced gastric barrier function [22]. Although further studies are needed to clarify the particular function of each mucin under various conditions, the increase in sialomucin may have contributed to the initiation and progression of recovery from loxoprofen sodium-induced mucosal injury in the rat small intestine observed in this study.…”

Effects of indomethacin on the rat small intestinal mucosa: immunohistochemical and biochemical studies using anti-mucin monoclonal antibodies

“…Previous reports have documented that the mucus charge elicited by the presence of sialic acid residues can contribute to the high viscosity of mucin, leading to enhancement of the gastric barrier function [31]. Although further studies are needed to clarify the particular function of each mucin under various situations, the increase of sialomucin and the reduction of sulfomucin may contribute to the initiation and progression of the recovery of indomethacin-induced mucosal injury in the rat small intestine.…”

“…The multilaminated structure possibly reflects different physicochemical properties of the different types of mucins secreted simultaneously from the same goblet cell or separately from the goblet cells lining the different levels of the crypts. Sialic acid usually occupies the terminal position of the oligosaccharide of the glycoconjugate and these terminal residues have a significant influence on the mucus charge, mucus rheology, and mucus degradation [31]. So, in this way, the multilaminated structure of sialomucin probably contributes to the high viscosity of the mucus lining and protects the endothelial layers of the intestine.…”