title: Expression of Toll-like receptor 4 in lungs of immune-suppressed rat withAcinetobacter baumanniiinfection.
abstract: Toll-like receptor 4 (TLR4) is involved in the regulation of host responses toAcinetobacter baumannii(A. baumannii). The aim of the present study was to examine the function of TLR4 in lung inflammation in immune-suppressed rats withA. baumanniiinfection. A total of 72 Sprague-Dawley male rats were randomly divided into the control,A. baumanniiinfection and immune-suppressed infection groups. The immune-suppressed infection group was treated with 100 mg/kg hydrocortisone by subcutaneous injection every other day for 2 weeks prior toA. baumanniiinfection. Lung tissue was obtained on the 3rd and 7th day after tracheal inoculation withA. baumannii. The expression of TLR4 in bronchial and alveolar epithelial cells, and alveolar macrophage was examined using immunohistochemistry. The levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid were detected using ELISA. The results showed that in the control group, the expression of TLR4 was upregulated in the bronchial and alveolar epithelial, and alveolar macrophages, and the levels of IL-6 and TNF-α were increased in the early phase ofA. baumanniiinfection. On the 7th day, no significant difference in the levels of IL-6 and TNF-α was observed between theA. baumanniiinfection and control groups. Conversely, the expression of TLR4 was downregulated in the immune-suppressed group, and the levels of IL-6 and TNF-α were reduced on the 3rd day after infection. In the subsequent observation period, the expression of TLR4 was upregulated and the levels of IL-6 and TNF-α were increased. In conclusion, the results show a critical role of TLR4 in mediating effective immune response in the lung of rat withA. baumanniiinfection.
authors.affiliation: Department of Intensive Care Unit, Sichuan Second Hospital of Traditional Chinese Medicine, Chengdu, Sichuan 610031, P.R. China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China.
authors.forename: Xuanlin
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China.
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Deng
authors.affiliation: Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Zong-An
authors.initials: ZA
authors.lastname: Liang
keywords: Acinetobacter baumannii; Toll-like receptor 4; immunosuppression; inflammation