title: Inflammatory cytokines, pleuropneumonia infection and the effect of dexamethasone.
abstract: OBJECTIVE
  Actinobacillus pleuropneumoniae causes an often fatal infection of swine due to pleuropneumonia. To determine if inflammatory cytokines are associated with A. pleuropneumoniae-induced pneumonia, infected and noninfected animals were concomitantly administered saline or dexamethasone.
  
  
  METHODS
  Twenty-four swine were treated with saline, A. pleuropneumoniae, dexamethasone, or A. pleuropneumoniae and dexamethasone (n = 6). The plasma levels of TNF-alpha, IL-1beta, IL-6, IL-8, and IL-10 were examined through time of necropsy (72 h). Gross pathology and histopathology was performed on all animals.
  
  
  RESULTS
  Dexamethasone had no effect on A. pleuropneumoniae-induced increases in lung/body weight ratios. Gross pathology of the infected pigs included fibrinous pleuropneumonia with necrosis and hemorrhage in a focal to a multifocal pattern. Histopathology of infected pig lungs revealed necrotizing extensive, fibrinopurulent pneumonia with edema and fibrinopurulent pleuritis. Plasma IL-6 levels were elevated in A. pleuropneumoniae-infected animals beginning 6 h after infection. Dexamethasone treatment did not alter A. pleuropneumoniae-induced plasma IL-6 levels. A. pleuropneumoniae infection did not elicit plasma levels of TNF-alpha, IL-1beta, IL-8, or IL-10.
  
  
  CONCLUSIONS
  These results suggest that the pneumonia caused by A. pleuropneumoniae infection is not due to the release of systemic inflammatory cytokines.
authors.affiliation: Division of Animal Research, US FDA, Center for Veterinary Medicine, Laurel, MD 20708, USA. mmeyers@cvm.fda.gov
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Myers
authors.forename: Dorothy E
authors.initials: DE
authors.lastname: Farrell
authors.forename: T G Ron
authors.initials: TG
authors.lastname: Snider
authors.forename: Lynn O
authors.initials: LO
authors.lastname: Post
mesh_terms: D016977:Actinobacillus pleuropneumoniae / Q000276:immunology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D016207:Cytokines / Q000097:blood / Q000187:drug effects* / Q000276:immunology; D003907:Dexamethasone / Q000627:therapeutic use*; D007249:Inflammation / Q000276:immunology; D008168:Lung / Q000187:drug effects / Q000276:immunology / Q000473:pathology*; D010994:Pleura / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D011001:Pleuropneumonia / Q000188:drug therapy* / Q000276:immunology / Q000662:veterinary*; D013552:Swine
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D003907:Dexamethasone