By the histochemical and biochemical methods, the structural changes of mucopolysaccharides of the gastric and duodenal mucosa were investigated.
1) The normal gastric and duodenal mucosa of rat are covered by two kinds of thin layer. One of these is a superficial layer consisted of glycoprotein, which is stained well by P.A.S. and Mowry's alcian blue, but poorly by Scott's alcian blue, and the other is a profound layer consisted of mucoprotein, which is stained well by Scott's alcian blue. The gastric mucosa is covered well with glycoprotein layer, but poorly with mucoprotein layer, and the duodenal mucosa poorly with glycoprotein layer, but well with mucoprotein layer.
2) Bile makes marked depletion of the glycoprotein layer, but gastric juice does not, and gastric juice makes destruction of the mucoprotein layer, but bile does not. These differences of resistance of the gastric and duodenal mucosa against to bile and gastic juice, and the differences of structures of mucopolysaccharides in the gastric and duodenal mucosa are the important factors contributed to the difference of pathogenesis between gastric and duodenal ulcer.
3) When the gastric mucosa is treated with urea, together with mucopolysaccharase and gastric juice, the mucosa is destructed remarkably with depletion of the thin layers.
4) Effect of histamine or gastrin as an aggressive factor, and effect of prednisone or mucopolysaccharase as a destructive factor in the protective mechanism, on pathogenesis of peptic ulcer were observed. When gastrin together with mucopolysaccharase are injected into the peritoneal cavity of rat, peptic ulcer occurs most frequently.
5) When rat is treated with serotonine and under goes stress of confinement, multiple peptic ulcers occur with disappearance of the mucous layers and with activation of lysosomal enzymes corresponding to the lesion, where there are marked changes in microcirculation around the muscularis mucosae.
Therefore, these findings suggest that destruction of the mucous layers is one of the important factors on pathogenesis of peptic ulcer.
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