大肠杆菌肺炎模型老龄大鼠的小肠分泌型IgA和肿瘤坏死因子的观测

目的：探讨老年肺炎时小肠损伤的发病机制。方法：复制大鼠大肠杆菌肺炎模型，分为青年对照组、青年模型组、老龄对照组和老龄模型组。观测肺脏和小肠组织病理改变及其组织含水量，肠内容物分泌型IgA（sIgA),IgA含量，血清和小肠组织肿瘤坏死因子（TNF）含量。结果：青年和老龄模型组肺和小肠组织损伤和含水量增高明显，其中老龄模型组大鼠肺组织损伤较青年模型组严重。青年模型组肠内容物sIgA含量的增高较青年对照组显著，老龄对照组sIgA高于青年对照组，老龄模型组sIgA低于老龄对照组。青年模型组和老龄模型组血清和小肠组织TNF的增高分别较青年对照组和老龄对照组显著，老龄模型组和血清和小肠组织TNF含量高于青年模型组。结论：TNF含量增多和sIgA含量变化与肺炎的肠道损伤发生发展有关密切关系，TNF增多及sIgA含量减少在老龄肺炎大鼠的变化更为显著。

Changes in intestinal sIgA and tumor necrosis factor in aged rats with Escherich ia coli pneumonia

Objective:To investigate the pathogenic mechanism underlying intestinal injury in aged rats with pneumonia.Methods:A model of Escherichia coli pneumonia was replicated in rats and they were divided into young control group (YCG),young model group (YMG),aged control group (ACG) and aged model group (AMG).The pathological changes in lung and intestine,the sIgA and IgA levels of intestinal contents,and the tumor necrosis factor (TNF) content in blood and intestine were observed.Results:Lung and intestinal injury were pronounced in the AMG compared with that in the YCG.The sIgA levels were higher in YMG than that in the YCG,the sIgA levels were obviously increased in ACG than that in the YCG,and the sIgA levels were lower in AMG than that in ACG and YMG.Compared with those in YCG and ACG,TNF contents in blood and intestine were obviously higher in YMG and AMG respectively,and among them blood and intestinal TNF levels were higher in AMG than those in YMG.Conclusions:The elevation of TNF contents and the decrease in sIgA might be related to intestinal injury in rats with pneumonia,and these changes are especially pronounced in the aged rats with pneumonia.