肠外肠内营养对腹腔感染大鼠肠上皮紧密连接和屏障功能的影响

目的　探讨肠外肠内营养对腹腔感染大鼠肠上皮紧密连接和屏障功能的影响。方法　14只存活6d的腹腔感染SD大鼠分别给予肠外营养(PN组)、肠外营养 肠内营养(PN EN组)。两组动物供给等热、等氮量。第6天处死动物,取末段回肠和结肠采用免疫组化法测定其跨膜结合蛋白(occludin)表达及肠上皮浆细胞IgA表达并定量;取腔静脉血及肺、肝、肠系膜淋巴组织匀浆后作细菌培养测细菌易位率;取门静脉血经鲎试剂法检测内毒素含量。结果　PN EN组小肠和大肠occludin及IgA表达明显优于PN组(P <0 .0 5及P <0 .0 1) ;血、肺、肝、肠系膜淋巴组织的细菌易位率和内毒素水平均低于PN组(P <0 .0 5 )。结论　肠内营养提高了肠上皮occludin表达,增加了肠道IgA的分泌,改善机械及免疫屏障,从而减少细菌易位。

Effects of enteral and parenteral nutrition on gut epithelial tight junction and immune barrier of rats with abdominal infection

Objective To investigate the effect of enteral and parenteral nutrition on gut microecology in rats with abdominal infection. Methods Fourteen Sprague-Dawley (SD) model rats of abdominal infection, which had survived for more than 6 days were divided into two groups: PN group ( n =7) and PN EN group ( n =7) via jejunostomy and jugular vein respectively for another 5 days. The nutrition support in the two groups was isonitrogen and isocaloric. At sacrifice on the sixth day, occludin and IgA level in plasma cells of intestine epithelium of the gut were measured by immunohistochemistry. Vena cava blood and homogenated tissue of liver, lung and mesenteric lymph nodes were cultured to determine bacterial translocations, and portal vein blood was tested for endotoxin. Results The expression of occludin and IgA in the small and large intestine in PN EN group were stronger than PN group ( P <0.05, P <0.01). Bacterial translocations in blood, liver, lung and mesenteric lymph nodes, and the level of endotoxin were significantly reduced in PN EN group ( P <0.05, P <0.01). Conclusion PN EN may increase the expression of transmember binding proteins and IgA, maintaining the intestinal epithelial tight junction and the immune function, hence decreasing gut bacterial translocations.