title: Altered surfactant protein A gene expression and protein homeostasis in rats with emphysematous changes.
abstract: BACKGROUND
  The decrease of surfactant protein (SP) secreted by the alveolar type II cell is one of the important causes of limiting air of pulmonary emphysema. However, the SP-A gene and protein changes in this disease are rarely studied. This study was undertaken to investigate alterations in SP-A gene activity and protein, and to explore their roles in the pathogenesis of emphysematous changes.
  
  
  METHODS
  Twenty Wistar rats were divided randomly into a normal control group (n = 10) and a cigarette smoking (CS) + lipopolysaccharide (LPS) group (n = 10). Ultra-structural changes were observed under an electron microscope. The number of cells positive for SP-A was measured by immunohistochemistry. The mRNA expression and protein level of SP-A in the lung tissues were determined by quantitative polymerase chain reaction (qPCR) and Western blot separately. The protein level of SP-A in lavage fluid was determined by Western blot.
  
  
  RESULTS
  The number of cells positive for SP-A of the CS + LPS group (0.35 +/- 0.03) was lower than that of the blank control group (0.72 +/- 0.06, P < 0.05). The level of SP-A in the lung tissues of rats in the CS + LPS group (0.2765 +/- 0.0890) was lower than that in the blank control group (0.6875 +/- 0.1578, P < 0.05). The level of SP-A in the lavage fluid of rats in the CS + LPS group (0.8567 +/- 0.1458) was lower than that in the blank control group (1.3541 +/- 0.2475, P < 0.05). The lung tissues of rats in the CS + LPS group showed an approximate increase (0.4-fold) in SP-A mRNA levels relative to beta-actin mRNA (P < 0.05).
  
  
  CONCLUSIONS
  The changes of SP-A may be related to emphysematous changes in the lung. And cigarette smoke and LPS alter lung SP-A gene activity and protein homeostasis.
authors: Department of Respiratory Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors: Qiong-jie
authors: QJ
authors: Hu
authors: Sheng-dao
authors: SD
authors: Xiong
authors: Hui-lan
authors: HL
authors: Zhang
authors: Xue-mei
authors: XM
authors: Shi
authors: Yong-jian
authors: YJ
authors: Xu
authors: Zhen-xiang
authors: ZX
authors: Zhang
authors: Guo-hua
authors: GH
authors: Zhen
authors: Jian-ping
authors: JP
authors: Zhao
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004646:Emphysema / Q000378:metabolism* / Q000473:pathology; D006706:Homeostasis; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D016133:Polymerase Chain Reaction; D037662:Pulmonary Surfactant-Associated Protein A / Q000032:analysis / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D037662:Pulmonary Surfactant-Associated Protein A; D012333:RNA, Messenger