title: Effect of ischemia and reperfusion on neutrophil accumulation in equine microvascular tissue flaps.
abstract: OBJECTIVE
  To investigate neutrophil accumulation after ischemia and reperfusion (IR) in microvascular tissue flaps in horses.
  
  
  METHODS
  Randomized controlled experiment.
  
  
  METHODS
  A total of 8 horses between 1 and 10 years of age, 4 of each sex.
  
  
  METHODS
  Control and experimental myocutaneous island flaps based on the superficial branch of the deep circumflex iliac vessels were dissected on each horse. Atraumatic vascular clamps were applied to the pedicle of the experimental flap for 90 minutes and then removed to allow reperfusion. Based on the assumption that rapid infiltration of neutrophils into affected tissues is a hallmark of IR injury, radiolabeled autogenous leukocytes were used to indirectly quantify neutrophil accumulation in flap tissues. Labeled leukocytes were administered through a jugular catheter 30 minutes before flap reperfusion. Biopsies were collected from each flap over a 6 hour postischemia time period; in group 1 (n = 4) from 0 to 6 hours postischemia, and in group 2 (n = 4) from 24 to 30 hours postischemia. Biopsies were examined scintigraphically and histologically for evidence of neutrophil infiltration.
  
  
  RESULTS
  All control flaps survived and 6 of 8 experimental flaps survived. There was no significant evidence of acute neutrophil infiltration into flap tissues after reperfusion in either group.
  
  
  CONCLUSIONS
  The results of this study suggest that equine myocutaneous flap tissues can survive a 90-minute ischemic period and reperfusion. No significant evidence of the occurrence of IR injury in flap tissues was found.
  
  
  CONCLUSIONS
  The reasons for the previously reported failures of equine free tissue transfer remain uncertain, but they do not appear to be caused by neutrophil mediated injury associated with ischemia and reperfusion.
authors.affiliation: Department of Veterinary Anesthesiology, Radiology, and Surgery, Western College of Veterinary Medicine, Saskatchewan, Canada.
authors.forename: W M
authors.initials: WM
authors.lastname: Scott
authors.forename: J D
authors.initials: JD
authors.lastname: Fowler
authors.forename: G
authors.initials: G
authors.lastname: Matte
authors.forename: A L
authors.initials: AL
authors.lastname: Allen
authors.forename: A A
authors.initials: AA
authors.lastname: Wilkinson
authors.forename: J V
authors.initials: JV
authors.lastname: Bailey
authors.forename: P B
authors.initials: PB
authors.lastname: Fretz
mesh_terms: D000818:Animals; D003250:Constriction; D005260:Female; D006736:Horses / Q000293:injuries / Q000601:surgery*; D007083:Iliac Artery / Q000601:surgery; D007511:Ischemia / Q000378:metabolism*; D008297:Male; D008866:Microsurgery / Q000009:adverse effects; D009504:Neutrophils / Q000378:metabolism*; D015427:Reperfusion Injury / Q000473:pathology*; D013524:Surgical Flaps / Q000473:pathology*