Immunology and Infectious Disease Research Group, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
J Occup Med Toxicol. 2008 Oct 30;3:24. doi: 10.1186/1745-6673-3-24.
Swine barn air contains endotoxin and many other noxious agents. Single or multiple exposures to pig barn air induces lung inflammation and loss of lung function. However, we do not know the effect of exposure to pig barn air on inflammatory response in the lungs following a secondary infection. Therefore, we tested a hypothesis that single or multiple exposures to barn air will result in exaggerated lung inflammation in response to a secondary insult with Escherichia coli LPS (E. coli LPS).
We exposed Sprague-Dawley rats to ambient (N = 12) or swine barn air (N = 24) for one or five days and then half (N = 6/group) of these rats received intravenous E. coli LPS challenge, observed for six hours and then euthanized to collect lung tissues for histology, immunohistochemistry and ELISA to assess lung inflammation.
Compared to controls, histological signs of lung inflammation were evident in barn exposed rat lungs. Rats exposed to barn air for one or five days and challenged with E. coli LPS showed increased recruitment of granulocytes compared to those exposed only to the barn. Control, one and five day barn exposed rats that were challenged with E. coli LPS showed higher levels of IL-1beta in the lungs compared to respective groups not challenged with E. coli LPS. The levels of TNF-alpha in the lungs did not differ among any of the groups. Control rats without E. coli LPS challenge showed higher levels of TGF-beta2 compared to controls challenged with E. coli LPS.
These results show that lungs of rats exposed to pig barn air retain the ability to respond to E. coli LPS challenge.
猪舍空气中含有内毒素和许多其他有害剂。单次或多次暴露于猪舍空气中会引起肺部炎症和肺功能丧失。然而，我们不知道在二次感染后暴露于猪舍空气中对肺部炎症反应的影响。因此，我们提出了一个假设，即单次或多次暴露于谷仓空气中会导致对大肠杆菌 LPS（E. coli LPS）的二次损伤产生过度的肺部炎症反应。
我们将 Sprague-Dawley 大鼠暴露于环境（N = 12）或猪舍空气（N = 24）中 1 天或 5 天，然后将这些大鼠中的一半（N = 6/组）接受静脉内大肠杆菌 LPS 挑战，观察 6 小时，然后处死收集肺组织进行组织学、免疫组织化学和 ELISA 评估肺部炎症。
与对照组相比，暴露于谷仓空气中的大鼠肺部有明显的肺部炎症组织学迹象。暴露于谷仓空气 1 天或 5 天并接受大肠杆菌 LPS 挑战的大鼠与仅暴露于谷仓的大鼠相比，粒细胞募集增加。暴露于谷仓空气 1 天或 5 天并接受大肠杆菌 LPS 挑战的对照组大鼠的肺部 IL-1beta 水平高于未接受大肠杆菌 LPS 挑战的相应组。各组肺组织中的 TNF-α水平无差异。未接受大肠杆菌 LPS 挑战的对照大鼠的 TGF-β2 水平高于接受大肠杆菌 LPS 挑战的对照大鼠。
这些结果表明，暴露于猪舍空气中的大鼠肺部仍有能力对大肠杆菌 LPS 挑战做出反应。
