title: Expression of triggering receptor-1 in myeloid cells of mice with acute lung injury.
abstract: BACKGROUND
  Myeloid cell (TREM-1) is an important mediator of the signal transduction pathway in inflammatory response. In this study, a mouse model of acute lung injury (ALI) by intraperitoneal injection of lipopolysaccharide (LPS) was established to observe the expression pattern of TREM-1 in lung tissue and the role of TREM-1 in pulmonary inflammatory response to ALI.
  
  
  METHODS
  Thirty BALB/C mice were randomly divided into a normal control group (n=6) and an ALI group (n=24). The model of ALI was made by intraperitonal injection of LPS in dose of 10 mg/kg. Specimens from peripheral blood and lung tissue were collected 6, 12, 24 and 48 hours after LPS injection. RT-PCR was used to detect TREM-1 mRNA, and ELISA was employed for detection of TREM-1 protein and TNF-a protein, and HE staining was performed for the pathological Smith lung scoring under a light microscope.
  
  
  RESULTS
  The expressions of TREM-1 mRNA in lung tissue and blood of the ALI group 6, 12, 24, and 48 hours after injection of LPS were higher than those in the control group. The levels of TREM-1 protein and the levels of TNF-a protein in lung tissue of the ALI group 6, 12, 24, and 48 hours after LPS injection were higher than those of the control group; the level of TREM-1 protein peaked 12 hours after LPS injection, but it was not significantly correlated with the expression of TREM-1 mRNA (P=0.14); the TNF-a concentration was positively correlated with TREM-1 levels in lung tissue and with Smith pathological score (r=0.795, P=0.001:r=0.499, P=0.034), but not with the expression of TREM-1 mRNA (P=0.176).
  
  
  CONCLUSIONS
  The expression of TREM-1 mRNA in lung tissue of mice with ALI is elevated, and the expression of TREM-1 mRNA is related to the level of TNF-a and the severity of inflammatory response to ALI. The expressions of the TREM-1 gene are not consistent with the levels of TREM-1 protein, suggesting a new functional protein involved in immune regulation.
authors.affiliation: Intensive Care Unit, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 , China.
authors.forename: Ning
authors.initials: N
authors.lastname: Liu
authors.affiliation: Intensive Care Unit, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 , China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Gu
authors.affiliation: Intensive Care Unit, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 , China.
authors.forename: Yi-Shan
authors.initials: YS
authors.lastname: Zheng
keywords: Acute lung injury; Expression; Myeloid cell; Pathological scoring; Triggering receptor-1; Tumor necrosis factor