title: Cerebral microdialysis of interleukin (IL)-1beta and IL-6: extraction efficiency and production in the acute phase after severe traumatic brain injury in rats.
abstract: BACKGROUND
  As a research tool, cerebral microdialysis might be a useful technique in monitoring the release of cytokines into the extracellular fluid (ECF) following traumatic brain injury (TBI). We established extraction efficiency of Interleukin(IL)-1ss and Interleukin(IL)-6 by an in vitro microdialysis-perfusion system, followed by in vivo determination of the temporal profile of extracellular fluid cytokines after severe TBI in rats.
  
  
  METHODS
  In vitro experiments using a polyether sulfon (PES) microdialysis probe especially developed for recovery of macromolecules such as cytokines, were carried out to establish the extraction efficiency of IL-1ss and IL-6 from artificial cerebrospinal fluid (CSF) with defined IL-1ss and IL-6 concentrations. In vivo experiments in which rats were subjected to TBI or sham and microdialysis samples were collected from the parietal lobe for measurement of cytokines.
  
  
  RESULTS
  The extraction efficiency was maximal 6.05% (range, 5.97-6.13%) at 0.5 microl/min(-1) and decreased at higher flow rates. Both cytokines were detectable in the dialysates. Highest IL-1ss levels were found within 200 min, highest IL-6 concentrations were detected at later intervals (200-400 min). No differences were found between the TBI and control groups.
  
  
  CONCLUSIONS
  Cerebral microdialysis allows measurement of cytokine secretion in the ECF of brain tissue in rats.
authors.affiliation: Neurosurgical Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands. hedy.folkersma@vumc.nl
authors.forename: Hedy
authors.initials: H
authors.lastname: Folkersma
authors.forename: John J P
authors.initials: JJ
authors.lastname: Brevé
authors.forename: Fred J H
authors.initials: FJ
authors.lastname: Tilders
authors.forename: Leela
authors.initials: L
authors.lastname: Cherian
authors.forename: Claudia S
authors.initials: CS
authors.lastname: Robertson
authors.forename: W Peter
authors.initials: WP
authors.lastname: Vandertop
mesh_terms: D000208:Acute Disease; D000818:Animals; D001921:Brain / Q000276:immunology / Q000378:metabolism*; D001930:Brain Injuries / Q000276:immunology* / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D045604:Extracellular Fluid / Q000737:chemistry*; D053583:Interleukin-1beta / Q000032:analysis / Q000378:metabolism*; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism*; D008297:Male; D017551:Microdialysis / Q000379:methods*; D009448:Neurochemistry / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D053583:Interleukin-1beta; D015850:Interleukin-6