title: Limb ischemia-reperfusion differentially affects the periosteal and synovial microcirculation.
abstract: BACKGROUND
  Joints are privileged compartments that enjoy increased protection against the inflammatory reactions affecting the extremities. We hypothesized that the functional characteristics of the microvasculature would contribute to the differential defensive potential of the synovial membrane.
  
  
  METHODS
  We investigated the synovial microcirculatory reactions and compared them with those of the tibial periosteum in response to 60 min of total limb ischemia, followed by 180 min of ischemia-reperfusion (IR) in rats. Carrageenan/kaolin-induced knee monoarthritis, a neutrophil-driven synovial inflammation model, served as the positive control.
  
  
  RESULTS
  IR brought about a significant reduction in red blood cell velocity in the capillaries and increases in rolling and adherence of the neutrophil leukocytes in the postcapillary venules (intravital microscopy), in adhesion molecule expression (intercellular adhesion molecule-1 immunohistochemistry) and in xanthine oxidoreductase activity in the periosteum. These changes were also pronounced in carrageenan/kaolin-induced monoarthritis but were almost completely absent in the synovium after the IR challenge. Most importantly, even after IR and in carrageenan/kaolin monoarthritis, the synovial microcirculation was characterized by significantly greater red blood cell velocities than that in the periosteum under resting conditions.
  
  
  CONCLUSIONS
  The ischemic duration, which significantly affected the functional integrity of the periosteal microcirculation, did not bring about a marked deterioration in that of the synovial membrane, suggesting that the synovial microcirculation is less endangered to the consequences of short-term tourniquet exposure than the periosteum. The greater microcirculatory red blood cell velocities and lower IR-induced endothelial expression of intercellular adhesion molecule-1 in the synovial membrane might explain the greater resistance of this compartment to the inflammatory consequences of IR.
authors.affiliation: Institute of Surgical Research, University of Szeged, Szeged, Hungary.
authors.forename: Petra
authors.initials: P
authors.lastname: Hartmann
authors.forename: Gábor
authors.initials: G
authors.lastname: Erős
authors.forename: Renáta
authors.initials: R
authors.lastname: Varga
authors.forename: József
authors.initials: J
authors.lastname: Kaszaki
authors.forename: Dénes
authors.initials: D
authors.lastname: Garab
authors.forename: István
authors.initials: I
authors.lastname: Németh
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Rázga
authors.forename: Mihály
authors.initials: M
authors.lastname: Boros
authors.forename: Andrea
authors.initials: A
authors.lastname: Szabó
mesh_terms: D000818:Animals; D002351:Carrageenan / Q000633:toxicity; D004195:Disease Models, Animal; D006614:Hindlimb / Q000098:blood supply*; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007616:Kaolin / Q000633:toxicity; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D009504:Neutrophils / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000139:chemically induced / Q000503:physiopathology / Q000601:surgery; D010521:Periosteum / Q000098:blood supply* / Q000601:surgery; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000503:physiopathology*; D000074402:Synovectomy; D013583:Synovial Membrane / Q000098:blood supply*; D013977:Tibia / Q000098:blood supply* / Q000601:surgery; D014968:Xanthine Dehydrogenase / Q000378:metabolism
chemical_list: D018799:Intercellular Adhesion Molecule-1; D007616:Kaolin; D002351:Carrageenan; D014968:Xanthine Dehydrogenase