| Currently many studies showed that obstructive jaundice(OJ) will caused damage of the gut mucosal barrier.Gut mucosal barrier dysfunction in OJ is associated with bacterial translocation and endotoxin absorption in gut lumen,which will result in more severe complications such as sepsis and multiple organ failure(MOF).Mucus layer is the first line of gut mucosal barrier.The main mucus component in the intestine is MUC2 mucin, which is a large and heavily O-glycosylated gel-forming mucin.It forms enormous polymeric nets by C-terminal dimerisation and N-terminal trimerisation.MUC2 is secreted by intestinal globlet cell into mucus layer and plays a pivotal role in gut mucus barrier.As a key component of mucus layer,MUC2 protects epithelial cells from bacterial in gut lumen.It can also activates intestinal immune systerm and prevents luminal pathogens adhering to epithelial cells.When gut mucosal barrier was damaged,mucus layer will become thin and finally be broken.It can also caused changes of MUC2 expression and bacterial adhering to epithelial cells.The inflammation was triggered by unbalance of gut homeostasis.So making a study about OJ intestinal mucosal MUC2 will be very meaningful.OJ is a kind of diseases with obstruction biliary.These diseases can be classified into two categories.One category are benign diseases(including common bile duct stone,extra-hepatic bile duct stone and so on).The other category are malignant diseases(including biliary carcinoma,pancreatic head carcinoma and ampullary carcinoma).To date,surgery is main treatment for the malignant OJ diseases.But there are still debates over whether perform preoperative biliary drainage in patients with malignant OJ.Some investigators confirmed the effect of preoperative biliary drainage in reducing the postoperative and morbidity.Others think that preoperative biliarydrainage should not be routinely performed due to the complications associated with the procedure itself, which might outweigh the potential benefit of it.Second controversy is about which is the appropriate drainage method, internal biliary drainage(ID) or external biliary drainage(ED).Some studies showed that internal biliary drainage is better than external biliary drainage.Because it make the bile appear in gut, and can improved endoxemia and gut mucosal barrier dysfunction.However,the mechanism remains to be unclear.The purpose of this study is to explore the effects of internal and external biliary drainage on expression of intestinal mucosal MUC2 in rats with OJ.The experiment contents are as follows:Objective: to explore the effects of internal and external biliary drainage on expression of intestinal mucosal MUC2 in rats with OJ.Methods: 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(IHC).Results:1 The endotoxin of OJ group rats were significance higher than SH group rats(0.93±0.28EU/ml),(0.15±0.10EU/ml)(p<0.01).The endotoxin of ID group(0.21±0.12EU/ml) and ED group(0.44±0.20EU/ml) were dcreased when compared with OJ group(p<0.01).ID group is lower than ED group(p<0.05).The levels of TBIL(107.72±18.22?mol/L),ALT(122.82±36.23U/L),AST(409.48±73.06U/L) in OJ group were higher than SH group(21.46±3.45?mol/L),(40.79±9.24U/L),(88.72±29.31U/L)(p<0.01).The TBIL(30.51±12.44?mol/L),ALT(56.79±19.66U/L),AST(178.49±67.52U/L)of ID group were lower than OJ group(p<0.01).The TBIL(35.89±15.57?mol/L),ALT(59.44±20.11U/L),AST(109.09±38.06U/L) of ED group were lower than OJ group(p<0.01).The AST of ID group were higher than ED group(p<0.05).2 Histological examination showed the level of gut mucosal injury in OJ group rats(3.93 ± 1.10) were significantly higher than in SH group(0.28 ±0.40)(p<0.01).The villus height of OJ group(175.14±65.38?m) were lower than SH group(457.67±88.56?m)(p<0.01).The level of gut mucosal injury in ID and ED group were lower than OJ group(1.64±0.94),(2.81±0.75),(3.93±1.10)(p<0.01). The villus height of ID and ED group were higher than OJ group(324.85±65.84?m),(291.63±66.36?m),(175.14±65.38?m)(p<0.01).The level of gut mucosal injury in ID group were lower than ED group(p<0.05).The villus height of ID and ED groups had no difference(p=0.37).3 Periodic Alcian Blue-Acid Schiff(AB-PAS) staining showed the secretory activity of globlet cell(GC) in OJ group rats were significantly lower than in SH group(OD 0.16 ± 0.05),(OD 0.43 ± 0.06)(p<0.01).The thickness of OJ group were decreased compared with SH group(77.14 ±38.66?m),(316.50±52.32?m)(p<0.01).The secretory activity of ID and ED groups were higher than OJ group(OD 0.35 ± 0.05),(OD 0.26± 0.04),(OD0.16±0.05)(p<0.01). The mucus layer thickness of ID and ED group were increased cmpared with OJ group(257.47±80.57?m),(137.38 ±38.15?m),(77.14±38.66?m)(p<0.01).The secretory activity in ID group was higher than ED group(p<0.05).When compared with ED,the mucus layer thickness of ID group were significance increased(p<0.01).4 electron microscopic observation showed OJ group microvillus became sparse?fractured and disorder.There were less mucus in globlet cell of OJ group than SH?ID and ED groups.SH group may had more mucus than ID and ED group.5 According to immunohistochemical staining, reduced expression of MUC2 protein were detected in OJ group compared with SH group(OD0.16±0.02),(OD 0.46 ± 0.03)(p<0.01).The expression of ID and ED groups were significance higher than OJ(OD 0.39±0.03),(OD 0.33±0.03)(p<0.01). ID group's expression were higher than ED(p<0.05).Conclusion:We concluded that MUC2 plays an key role in maintain the intestinal barrier.The reduced expression of MUC2 and secretion of gobletcells is an important mechanism involved in intestinal injury of OJ.Internal drainage and external drainage increased expression of MUC2 and secretion of goblet cells.Internal drainage may be a better way to inducing expression of MUC2 and repairing the mucus layer of OJ than external drainage. |
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