title: Evaluation of a porcine model to study in vivo platelet activation.
abstract: BACKGROUND
  In order to investigate if decompression sickness involves platelet activation an animal model was evaluated.
  
  
  METHODS
  Twenty-four thiopentone-midazolam-fentanyl-anaesthetized pigs in four groups received 5-min infusions of adenosine diphosphate (25 mg/kg) or platelet activating factor (0.4 microg/kg). Groups 1 and 2 (adenosine diphosphate, n=6 and platelet activating factor, n=6) were studied for 30 min and then sacrificed. Groups 3 and 4 (adenosine diphosphate, n=6 and platelet activating factor, n=6) were sacrificed immediately afterwards to study short-term changes. Haemodynamics, platelet counts and post mortem lung platelet aggregates were registered. Groups 1 and 2 also had indium platelet labelling, lung scintigraphy and platelet accumulation index calculations performed.
  
  
  RESULTS
  Adenosine diphosphate induced immediate and more profound transient shocks. Platelet and leukocyte count decreases and occurrences of post mortem lung platelet aggregates were significantly more profound in the 5-min adenosine diphosphate group (Group 3) than in the platelet activating factor group (Group 4). With platelet labelling there were positive platelet accumulation index trends in the 30-min adenosine diphosphate group (Group 1). Adenosine diphosphate also produced platelet aggregation in platelet-rich porcine plasma. Only adenosine diphosphate (an intermediate platelet agonist) showed signs of platelet activation when considering all platelet parameters. The model should be further evaluated with different bolus doses of adenosine diphosphate, but may be used to evaluate if gas bubbles introduced into the circulation (as with decompression sickness), or possibly if clinical drugs, might produce platelet activation in vivo.
authors.affiliation: Department of Biomedicine, University of Bergen, N-5021 Bergen, Norway. eirik.softeland@biomed.uib.no
authors.forename: Eirik
authors.initials: E
authors.lastname: Søfteland
authors.forename: Tore
authors.initials: T
authors.lastname: Framstad
authors.forename: Astrid
authors.initials: A
authors.lastname: Nordvik
authors.forename: Anne M
authors.initials: AM
authors.lastname: Bakken
authors.forename: Chandru
authors.initials: C
authors.lastname: Punwani
authors.forename: Inge
authors.initials: I
authors.lastname: Morild
authors.forename: Tor
authors.initials: T
authors.lastname: Hervig
authors.forename: Terje
authors.initials: T
authors.lastname: Thorsen
authors.forename: Holm
authors.initials: H
authors.lastname: Holmsen
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000276:immunology*; D002478:Cells, Cultured; D003665:Decompression Sickness / Q000276:immunology* / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D008297:Male; D015539:Platelet Activation / Q000276:immunology*; D013552:Swine