Changes of ultramicrostructure in gastric mucusal epithelial cell, parietal cell and the effect of platelet-activating factor antagonist on young rats with endotoxemia

Abstract

Objective To investigate the changes of ultramicrostructure in gastric mucosal epithelial cell,parietal cell and effect of platelet activating factor(PAF) antagonist in young rats with endotoxernia.Methods Eighteenday old Wistar rats were randomly divided into four groups:control,model,prevention and treatment group.The rats of control group and modal group were done with intraperitoneal injection of normal saline (1 ml/kg) and endotoxin (5 mg/kg of O55:B5 lipopolysaccharide) respectively.The rats of prevention and treatment group were repectively administered with PAF antagonist BN52021(GinkgolideB 5 mg/kg) half an hour before and after injected with endotoxin.And then,we observed the changes of gastric mucosa at 1.5,3,6,24,48 and 72 hours after intraperitonesl injection of endotoxin,recorded the ulcer index(UI) of gastric mucosa according to Guth standard integral.The changes of celluar morphology and ultramicrostructure of gastric mucosa were respectively observed by hematoxylin-ecsion staining and transmission electron micrsoope.The ratio of wet and dry weight of gastric mucosa was also calculated.Resalts Gastric muoosal injury of rats were most serious at 6 hours after injection of endotoxin in rnodd group,there was quite a lot of erosio,bleeding and necrosis and the UI score was highest in model group,there was highly significant difference between model group and other three groups(P＜0.01).There was shedding of surface epithelium,bleeding in muoosa,inflammatory cell infiltrate,and damage of glandular organ in model group,and also we could see that the cell spaces of epithelial cells were widened,surface of cavity and mucosa was damaged,tight junction between cells were damaged,microvilli decreased,and mitochondria were seriously swelled.Also there was vacuolar degeneration and pyknosis,nuclear membrane spaces were widened.All the above changs were significandy alleviated in prevention and treatment group.Conclusion The gastric mucosa of young rats with endotoxemia is injured,and the ultramicrostructure of gastric mucosal epithelial cell,parietal cell changes.PAF antagonist can obviously alleviate the acute gastric mucosal injury,and PAF may be the main factor that results in acute gastric mucosal injury during endotoxemia. Key words: Endotoxemia; Acute gastric mucosal injury; Ultrastructure; Platelet activating factor receptor antagonist; Rat