title: Serosal but not mucosal endotoxin exposure increases intestinal permeability in vitro in the rat.
abstract: BACKGROUND
  Microbial endotoxins are normally present in the gut, usually without apparent harmful effects, whereas systemically administered endotoxin impairs the mucosal barrier function. Our aim was to investigate whether in vitro exposure to bacterial lipopolysaccharide (LPS) could affect the intestinal barrier properties of the rat small intestine.
  
  
  METHODS
  Small-intestinal segments from rats were mounted in Ussing diffusion chambers, and the mucosal to serosal permeation of the marker molecules bovine serum albumin (BSA) and 51Cr-ethylenediaminetetraacetic acid (EDTA) was measured after addition of LPS to the mucosal or serosal side.
  
  
  RESULTS
  Mucosal exposure to LPS (0.01, 0.05, 0.25 mg/ml) had no effects on the permeation of BSA and 51Cr-EDTA, whereas when added to the serosal side at 0.05 or 0.25 mg/ml, LPS increased the marker permeation.
  
  
  CONCLUSIONS
  Serosal LPS exposure in vitro increased the intestinal permeability to the different-sized markers, whereas mucosal LPS did not, indicating that the mechanisms leading to intestinal barrier impairment can be initiated in the intestinal wall itself.
authors.affiliation: Dept. of Animal Physiology, Lund University, Sweden.
authors.forename: N E
authors.initials: NE
authors.lastname: Osman
authors.forename: B
authors.initials: B
authors.lastname: Weström
authors.forename: B
authors.initials: B
authors.lastname: Karlsson
mesh_terms: D000818:Animals; D018988:Bacterial Translocation / Q000502:physiology*; D002417:Cattle; D015194:Diffusion Chambers, Culture; D004492:Edetic Acid / Q000493:pharmacokinetics; D004797:Enzyme-Linked Immunosorbent Assay; D007408:Intestinal Absorption / Q000502:physiology*; D007413:Intestinal Mucosa / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology* / Q000633:toxicity; D008297:Male; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012704:Serous Membrane / Q000187:drug effects; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics
chemical_list: D008070:Lipopolysaccharides; D012710:Serum Albumin, Bovine; D004492:Edetic Acid