Sequential recruitment of neutrophils into lung and bronchoalveolar lavage fluid in LPS-induced acute lung injury

Am J Physiol Lung Cell Mol Physiol. 2005 Nov;289(5):L807-15. doi: 10.1152/ajplung.00477.2004. Epub 2005 Jun 10.


Infiltration of activated neutrophils [polymorphonuclear leukocytes (PMN)] into the lung is an important component of the inflammatory response in acute lung injury. The signals required to direct PMN into the different compartments of the lung have not been fully elucidated. In a murine model of LPS-induced lung injury, we investigated the sequential recruitment of PMN into the pulmonary vasculature, lung interstitium, and alveolar space. Mice were exposed to aerosolized LPS and bronchoalveolar lavage fluid (BAL), and lungs were harvested at different time points. We developed a flow cytometry-based technique to assess in vivo trafficking of PMN in the intravascular and extravascular lung compartments. Aerosolized LPS induced consistent PMN migration into all lung compartments. We found that sequestration in the pulmonary vasculature occurred within the first hour. Transendothelial migration into the interstitial space started 1 h after LPS exposure and increased continuously until a plateau was reached between 12 and 24 h. Transepithelial migration into the alveolar air space was delayed, as the first PMN did not appear until 2 h after LPS, reaching a peak at 24 h. Transendothelial migration and transepithelial migration were inhibited by pertussis toxin, indicating involvement of Galphai-coupled receptors. These findings confirm LPS-induced migration of PMN into the lung. For the first time, distinct transmigration steps into the different lung compartments are characterized in vivo.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bronchoalveolar Lavage Fluid / cytology
  • Cell Movement / drug effects
  • Lipopolysaccharides / toxicity
  • Lung / blood supply
  • Lung / drug effects
  • Lung / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophils / drug effects*
  • Neutrophils / pathology
  • Neutrophils / physiology
  • Pertussis Toxin / toxicity
  • Receptors, Chemokine / metabolism
  • Respiratory Distress Syndrome / etiology
  • Respiratory Distress Syndrome / pathology*
  • Respiratory Distress Syndrome / physiopathology
  • Time Factors


  • Gr-1 protein, mouse
  • Lipopolysaccharides
  • Receptors, Chemokine
  • Pertussis Toxin