title: Dexamethasone promotes ulcer plugging in experimental enteritis.
abstract: OBJECTIVE
  We investigated the effect of dexamethasone on indomethacin-induced ulceration in the rat.
  
  
  METHODS
  Groups of four rats received oral indomethacin (15 mg/kg) and the jejunal mucosa was examined 24 h later for mucosal ulceration. Three of the groups received oral dexamethasone (1, 3 and 6 mg/kg) 0.5 h prior to indomethacin, while the fourth received vehicle. Haematological evaluation was performed and ulcers were assessed both histologically and immunohistochemically.
  
  
  RESULTS
  Indomethacin caused multifocal jejunal ulceration that was reduced only by the highest dose of dexamethasone (6 mg/kg). Indomethacin caused a significant fall in the blood haemoglobin concentration that was prevented by dexamethasone at all doses. The ulcers induced by indomethacin alone were deep, punched-out and haemorrhagic while the ulcers arising in rats pre-treated with dexamethasone (all doses) were 'plugged' by a white fibrino-purulent exudate. Histologically, the dexamethasone ulcer exudate was composed of bacteria, fibrin, mucus and a significant increase in the numbers of neutrophils. Dexamethasone alone had no significant pathological effect on the small intestine.
  
  
  CONCLUSIONS
  We report the observation that dexamethasone at high doses inhibits indomethacin-induced jejunal ulceration in the rat while at low doses it promotes 'plugging' of ulcers with bacteria, fibrin, mucus and neutrophils that probably reduces haemorrhage from the ulcer base.
authors.affiliation: University Department of Histopathology, Royal Free Hospital, School of Medicine, London, UK.
authors.forename: A
authors.initials: A
authors.lastname: Anthony
authors.forename: A P
authors.initials: AP
authors.lastname: Dhillon
authors.forename: R
authors.initials: R
authors.lastname: Sim
authors.forename: R E
authors.initials: RE
authors.lastname: Pounder
authors.forename: A J
authors.initials: AJ
authors.lastname: Wakefield
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000627:therapeutic use*; D004751:Enteritis / Q000517:prevention & control*; D005337:Fibrin; D006403:Hematologic Tests; D007213:Indomethacin; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D007579:Jejunal Diseases / Q000517:prevention & control*; D008297:Male; D009093:Mucus; D009504:Neutrophils; D051381:Rats; D017207:Rats, Sprague-Dawley; D014456:Ulcer / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*
chemical_list: D003907:Dexamethasone; D005337:Fibrin; D007213:Indomethacin