title: Effects of continuous or intermittent lipopolysaccharide administration for 48 hours on the systemic inflammatory response in horses.
abstract: OBJECTIVE
  To determine whether the method of lipopolysaccharide (LPS) administration (intermittent vs continuous) affects the magnitude and duration of the systemic inflammatory response in horses and whether prolonged (48 hours) endotoxemia induces laminitis.
  
  
  METHODS
  12 healthy adult horses (10 mares and 2 geldings).
  
  
  METHODS
  Horses were randomly assigned to receive LPS (total dose, 80 μg; n = 4) or saline (0.9% NaCl) solution (80 mL/h; 4) via constant rate infusion or 8 bolus IV injections of LPS (10 μg, q 6 h;4) during a 48-hour period. Physical examinations were performed every 4 hours, inflammatory cytokine gene expression was determined for blood samples obtained every 8 hours, and IV glucose tolerance tests were performed.
  
  
  RESULTS
  All LPS-treated horses had signs of depression and mild colic; those signs abated as the study progressed. Administration of LPS increased expression of interleukin-1β, interleukin-6, and interleukin-8, but results were not significantly different between LPS treatment groups. Cytokine expression was significantly higher on the first day versus the second day of LPS treatment. Interleukin-1β expression was positively correlated with rectal temperature and expression of other cytokines. Glucose and insulin dynamics for both LPS groups combined did not differ significantly from those of the saline solution group. Signs of laminitis were not detected in any of the horses.
  
  
  CONCLUSIONS
  Horses developed LPS tolerance within approximately 24 hours after administration was started, and the method of LPS administration did not affect the magnitude or duration of systemic inflammation. Laminitis was not induced in horses.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Tadros
authors.forename: Nicholas
authors.initials: N
authors.lastname: Frank
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism; D019446:Endotoxemia / Q000097:blood / Q000139:chemically induced / Q000276:immunology / Q000662:veterinary*; D005260:Female; D005534:Foot Diseases / Q000097:blood / Q000139:chemically induced / Q000276:immunology / Q000662:veterinary*; D005951:Glucose Tolerance Test / Q000662:veterinary; D006734:Horse Diseases / Q000097:blood / Q000139:chemically induced* / Q000276:immunology*; D006736:Horses; D007249:Inflammation / Q000097:blood / Q000139:chemically induced / Q000276:immunology / Q000662:veterinary*; D007328:Insulin / Q000097:blood; D053583:Interleukin-1beta / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D008070:Lipopolysaccharides / Q000008:administration & dosage* / Q000276:immunology; D008297:Male; D011897:Random Allocation
chemical_list: D001786:Blood Glucose; D007328:Insulin; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides