title: Lipopolysaccharide induced inflammation in the perivascular space in lungs.
abstract: BACKGROUND
  Lipopolysaccharide (LPS) contained in tobacco smoke and a variety of environmental and occupational dusts is a toxic agent causing lung inflammation characterized by migration of neutrophils and monocytes into alveoli. Although migration of inflammatory cells into alveoli of LPS-treated rats is well characterized, the dynamics of their accumulation in the perivascular space (PVS) leading to a perivascular inflammation (PVI) of pulmonary arteries is not well described.
  
  
  METHODS
  Therefore, we investigated migration of neutrophils and monocytes into PVS in lungs of male Sprague-Dawley rats treated intratracheally with E. coli LPS and euthanized after 1, 6, 12, 24 and 36 hours. Control rats were treated with endotoxin-free saline. H&E stained slides were made and immunohistochemistry was performed using a monocyte marker and the chemokine Monocyte-Chemoattractant-Protein-1 (MCP-1). Computer-assisted microscopy was performed to count infiltrating cells.
  
  
  RESULTS
  Surprisingly, the periarterial infiltration was not a constant finding in each animal although LPS-induced alveolitis was present. A clear tendency was observed that neutrophils were appearing in the PVS first within 6 hours after LPS application and were decreasing at later time points. In contrast, mononuclear cell infiltration was observed after 24 hours. In addition, MCP-1 expression was present in perivascular capillaries, arteries and the epithelium.
  
  
  CONCLUSIONS
  PVI might be a certain lung reaction pattern in the defense to infectious attacks.
authors.affiliation: Dept. of Functional and Applied Anatomy -4120-, Medical School of Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Tschernig
authors.affiliation: Immunology Research Group, Departments of Veterinary Biomedical Sciences and Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, S7N 5B4, Canada.|Diagnostic Medicine and Pathobiology, 1800 Denison Avenue, Kansas State University, Manhattan, Kansas 66506, USA.
authors.forename: Kyathanahalli S
authors.initials: KS
authors.lastname: Janardhan
authors.affiliation: Dept. of Functional and Applied Anatomy -4120-, Medical School of Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Pabst
authors.affiliation: Immunology Research Group, Departments of Veterinary Biomedical Sciences and Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, S7N 5B4, Canada.
authors.forename: Baljit
authors.initials: B
authors.lastname: Singh