title: Presence of mononuclear cells in normal and affected laminae from the black walnut extract model of laminitis.
abstract: BACKGROUND
  There is increasing evidence of involvement of inflammatory cells in acute laminitis.
  
  
  OBJECTIVE
  To immunolocalise monocytes/macrophages and B and T lymphocytes in the laminar tissue of normal horses and those with black walnut extract (BWE)-induced laminitis.
  
  
  METHODS
  Immunohistochemistry was used in archived laminar tissue samples from 20 horses divided equally into 4 groups: control animals (CON), and those administered BWE at 1.5 h (1.5H DTP group), at the onset of leucopenia (3H DTP group) and at the onset of lameness (LAM group). Antibodies against CD3, CD20 and CD163 were used to recognise lymphocytes (T and B) and monocytes/macrophages, respectively.
  
  
  RESULTS
  Mononuclear cells were present in laminar tissue of normal horses. The majority of CD3- and CD20-positive lymphocytes were localised around the deep dermal vessels but were also evident around vessels of the primary dermal laminae. CD163-positive macrophages were primarily perivascular in deep dermis or in dermal laminae. No changes in the number of laminar B or T lymphocytes occurred at any time point post BWE administration. However, increases (P=0.0016) in laminar CD163-positive cells occurred in the secondary dermal laminae (SDL) in the 1.5H DTP and 3H DTP groups, returning to basal values in LAM group.
  
  
  CONCLUSIONS
  Lymphocyte and macrophage populations are present in the laminar tissue of clinically normal horses and BWE administration induces an increase in CD163-positive macrophages in SDL.
  
  
  CONCLUSIONS
  Both the host tissue population of mononuclear cells and the influx of monocytes may play an important role in the pathophysiological changes leading to laminar injury.
authors.affiliation: Department of Veterinary Clinical Sciences, Ohio State University, OH, USA.
authors.forename: R R
authors.initials: RR
authors.lastname: Faleiros
authors.forename: G J
authors.initials: GJ
authors.lastname: Nuovo
authors.forename: A D
authors.initials: AD
authors.lastname: Flechtner
authors.forename: J K
authors.initials: JK
authors.lastname: Belknap
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism; D005534:Foot Diseases / Q000473:pathology / Q000662:veterinary*; D006724:Hoof and Claw / Q000473:pathology; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D007249:Inflammation / Q000473:pathology / Q000662:veterinary*; D031324:Juglans / Q000633:toxicity; D007963:Leukocytes, Mononuclear / Q000145:classification / Q000166:cytology* / Q000378:metabolism*; D010936:Plant Extracts / Q000633:toxicity*
chemical_list: D000941:Antigens; D010936:Plant Extracts