title: Experimental cooling-induced preconditioning attenuates skin flap failure.
abstract: BACKGROUND
  Microvascular perfusion failure is a leading cause of tissue necrosis in reconstructive surgery. In the present experimental study the effect of local hypothermia was investigated as a possible preconditioning procedure that could induce stress proteins such as heat-shock protein (HSP) 70 and HSP-32 (haem oxygenase (HO) 1). The effect on flap microcirculation and survival was also studied.
  
  
  METHODS
  Ears of hairless mice were subjected to local hypothermia (30 min, 4 degrees C) 24 h before flap creation. A pedicled flap was elevated by incision of four-fifths of the base of the ear. Microcirculatory dysfunction and tissue necrosis were analysed quantitatively over 5 days by means of intravital fluorescence microscopy. HO-1 and HSP-70 protein expression were determined by western blot analysis. HO-1 distribution within the flap tissue was also analysed by immunohistochemistry. Animals with unconditioned flaps served as controls.
  
  
  RESULTS
  Cooling induced a marked expression of HO-1 without induction of HSP-70 protein. This was paralleled by a significant improvement in microvascular perfusion (P < 0.050) that was predominantly regulated by the dilatation of nutritive capillaries. The cooling-mediated improvement in microcirculation resulted in a significant reduction in final flap necrosis (P < 0.050).
  
  
  CONCLUSIONS
  In this experimental study preoperative cooling was associated with the expression of HO-1 and was an effective conditioning procedure.
authors.affiliation: Institute for Clinical and Experimental Surgery, University of Saarland, Homburg/Saar, Hannover, Germany. darius.kubulus@uniklinik-saarland.de
authors.forename: D
authors.initials: D
authors.lastname: Kubulus
authors.forename: M
authors.initials: M
authors.lastname: Amon
authors.forename: F
authors.initials: F
authors.lastname: Roesken
authors.forename: M
authors.initials: M
authors.lastname: Rücker
authors.forename: I
authors.initials: I
authors.lastname: Bauer
authors.forename: M D
authors.initials: MD
authors.lastname: Menger
mesh_terms: D000818:Animals; D062109:Dermatologic Surgical Procedures; D004423:Ear / Q000601:surgery*; D005260:Female; D006084:Graft Rejection / Q000209:etiology / Q000378:metabolism; D006085:Graft Survival; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D007036:Hypothermia, Induced / Q000379:methods*; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D008833:Microcirculation / Q000502:physiology; D012867:Skin / Q000378:metabolism; D013524:Surgical Flaps / Q000098:blood supply
chemical_list: D006360:Heat-Shock Proteins; D006419:Heme Oxygenase (Decyclizing)