| Obstructive jaundice(OJ) is frequently associated with various complications of infection which result from the damage of the gut mucosal barrier. The most severe complications of OJ are sepsis and multiple organ failure(MOF). In recent years, scholars at home and abroad place a very high value on the important mechanism of gut barrier dysfunction in obstructive jaundice. The mucus layers which is an important part of the gut mucosal barrier is the first barrier to resist the invasion of pathogen and harmful substance. It plays an important role in maintaining the function of the intestinal mucosal barrier.Mucin-2(MUC2) is a highly glycosylated protein, which is the most abundantly expressed mucin in the mucus layer.It is synthesized and secreted by goblet cells of the intestine and covers the gastrointestinal tract. It contains high concentrations of anti bacterial peptides and proteins and protects the epithelium against noxious agents, viruses, and pathogenic bacteria.It has been confirmed that loss and change of MUC2 allows bacteria to adhere to epithelial cells.When bacteria reach the epithelial surface,the immune system is activated and inflammation is triggered.This mechanism might occur in various gut diseases.However, the rule of MUC2 in obstructive jaundice remains to be elucidated.This study aims to explore the expression of MUC2 in the small intestine in OJ and the experiment contents are as follows:Objective: to investigate the roles of MUC2 in patients with malignant obstructive jaundice(MOJ).Methods: This study involved three groups, group A, MOJ patients whose bilirubin were 43 μm/L or higher, group B, MOJ patients with no jaundice and group C, patients who underwent gastroscopy with negative findings. We took biopsies in all participants at the second part of the duodenum, distal to the ampulla of Vater. The morphological changes of gut mucosa were observed by hematoxylin and eosin(HE) staining and electron microscopy(EM). The distributions and expressions of MUC2 in gut mucosa were evaluated by Periodic Alcian Blue-Acid Schiff(AB-PAS) staining and immunohistochemistry.Results: Histological examination showed some infiltration of the lamina propria by chronic inflammatory cells in MOJ patients with high levels of gut mucosal injury compared with no jaundice patients and control; The level of mucosal injury in MOJ patients(3.54±1.05) were significantly higher than in control group(1.13±0.35 vs. 1.10±0.57)(P<0.01). We found goblet cell secretory activity increased but depletion in numbers by AB-PAS staining in patients with MOJ( GC OD 0.15 ± 0.02) in contrast to the other two groups(GC OD 0.32±0.04 vs. 0.35±0.03)(P<0.01). Induced goblet cell compound exocytosis were observed with EM and in patients with MOJ too. According to immunohistochemical staining, reduced expression of MUC2 protein were detected in MOJ patients(MUC2 OD 0.18±0.03 vs. 0.36±0.08 vs. 0.34±0.07)(P<0.01).Conclusion:We therefore infer that MUC2 plays an important role in maintain the intestinal barrier and the compound exocytosis of goblet cells is an important protective mechanism involved in the prevention of intestinal injury in patients with MOJ which can relese an amount of MUC2 to repair the mucus layer. |
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