title: Lack of macrophage migration inhibitory factor in mice does not affect hallmarks of the inflammatory/immune response during the first week after stroke.
abstract: BACKGROUND
  Macrophage migration inhibitory factor (MIF) has been proposed to play a detrimental role in stroke. We recently showed that MIF promotes neuronal death and aggravates neurological deficits during the first week after experimental stroke, in mice. Since MIF regulates tissue inflammation, we studied the putative role of MIF in post-stroke inflammation.
  
  
  METHODS
  We subjected C57BL/6 mice, Mif-/- (MIF-KO) or Mif+/+ (WT), to a transient occlusion of the right middle cerebral artery (tMCAo) or sham-surgery. We studied MIF expression, GFAP expression and the number of CD74-positive cells in the ischemic brain hemisphere 7 days after tMCAo using primarily immunohistochemistry. We determined IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12, KC/CXCL-1 and TNF-α protein levels in the brain (48 h after surgery) and serum (48 h and 7 days after surgery) by a multiplex immunoassay.
  
  
  RESULTS
  We observed that MIF accumulates in neurons and astrocytes of the peri-infarct region, as well as in microglia/macrophages of the infarct core up to 7 days after stroke. Among the inflammatory mediators analyzed, we found a significant increase in cerebral IL-12 and KC levels after tMCAo, in comparison to sham-surgery. Importantly, the deletion of Mif did not significantly affect the levels of the cytokines evaluated, in the brain or serum. Moreover, the spleen weight 48 h and 7 days subsequent to tMCAo was similar in WT and MIF-KO mice. Finally, the extent of GFAP immunoreactivity and the number of MIF receptor (CD74)-positive cells within the ischemic brain hemisphere did not differ significantly between WT and MIF-KO mice subjected to tMCAo.
  
  
  CONCLUSIONS
  We conclude that MIF does not affect major components of the inflammatory/immune response during the first week after experimental stroke. Based on present and previous evidence, we propose that the deleterious MIF-mediated effects in stroke depend primarily on an intraneuronal and/or interneuronal action.
authors.affiliation: Laboratory for Experimental Brain Research, Department of Clinical Sciences, Lund University, BMC A13, 22184 Lund, Sweden. ana.inacio@med.lu.se
authors.forename: Ana R
authors.initials: AR
authors.lastname: Inácio
authors.forename: Richard
authors.initials: R
authors.lastname: Bucala
authors.forename: Tomas
authors.initials: T
authors.lastname: Deierborg
mesh_terms: D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D001921:Brain / Q000166:cytology / Q000276:immunology / Q000473:pathology; D018925:Chemokines / Q000097:blood / Q000276:immunology; D016207:Cytokines / Q000097:blood / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D020244:Infarction, Middle Cerebral Artery; D007249:Inflammation / Q000097:blood / Q000276:immunology* / Q000473:pathology; D018836:Inflammation Mediators / Q000097:blood / Q000276:immunology; D008263:Macrophage Migration-Inhibitory Factors / Q000235:genetics / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology / Q000276:immunology / Q000473:pathology; D013154:Spleen / Q000033:anatomy & histology / Q000378:metabolism; D020521:Stroke / Q000097:blood / Q000276:immunology* / Q000473:pathology*
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D018925:Chemokines; D016207:Cytokines; D000949:Histocompatibility Antigens Class II; D018836:Inflammation Mediators; D008263:Macrophage Migration-Inhibitory Factors; C045084:invariant chain