title: [Effects of different durations and times of ischemic preconditioning on ischemia-reperfusion injury to tram flaps in rats].
abstract: OBJECTIVE
  To determine whether the different durations and times of the ischemic preconditioning affect the effectiveness of the ischemic preconditioning.
  
  
  METHODS
  Ninety male Wistar rats were randomly divided into the control group and the eight preconditioned groups of 10 rats each. A transverse rectus abdominis musculocutaneous flap (TRAM) was elevated in each rat. The flaps were preconditioned by clamping the pedicle and reperfusing for 5 or 10 minutes per cycle. This was repeated for one or two cycles. The controls were simply perfused for 30 minutes. Each flap was then subjected to 4 hours of the global ischemia. Three rats in each group were killed for an estimate of the water content in the muscle and for observation on the muscular structure under microscope. The flap surface survival areas of the other rats were calculated on the 7th postoperative day by the computerized video planimetry.
  
  
  RESULTS
  The water content in the muscle was evidently reduced. The mean survival area of the flap in every preconditioned group increased by 2-3 times compared with that of the controls (P < 0.001). The different procedures of the ischemic preconditioning produced different protective effects.
  
  
  CONCLUSIONS
  The ischemic preconditioning is an available means to alleviate an ischemia-reperfusion injury to the transverse rectus abdominis musculocutaneous flap in rats. The effect of the ischemic preconditioning is affected by the duration and time of the ischemic preconditioning.
authors: Department of Orthopaedics and Microsurgery, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou Guangdong, 510080, PR China.
authors: Honggang
authors: H
authors: Wang
authors: Zhiyong
authors: Z
authors: Li
authors: Xioalin
authors: X
authors: Liu