Postconditioning attenuates ischemia‐reperfusion injury in rat skin flap

Abstract

Reperfusion injury by the abrupt restoration of circulation after the prolonged ischemia has been remained unsolved problem in the reconstructive microsurgery. We tested the hypothesis that a procedure of intermittent interruption of reperfusion, i.e., postconditioning (post-con) attenuates ischemia/reperfusion (I/R) injury of rat epigastric skin flap. A complete 4 hours of ischemia was generated by occlusion of the pedicle of dissected flap. The post-con procedure was started at the end of ischemia. A cycle of 15 seconds of full reperfusion, followed by 15 seconds of complete reocclusion was repeated six times (3 min of total intervention) prior to the unlimited reperfusion. Flap necrosis area of post-con group was compared with sham (no ischemic exposure) and control (4 hours of ischemia followed by full reperfusion without intervention) groups at postreperfusion day 5. Histology and MPO activities of flaps were evaluated. The post-con group showed significantly reduced flap necrosis at the end of 5 days of reperfusion compared with the control. Decreased inflammatory cell infiltration and MPO activity indicated post-con attenuated acute inflammatory reaction caused by I/R. This study reports for the first time that ischemic post-con effectively attenuates skin flap I/R injury. With further study, post-con may eventually be clinically applicable for the I/R injury as an "after-injury strategy."

Expression of inducible nitric oxide synthase in muscle flaps treated with ischemic postconditioning

“…Its therapeutic effects on muscle flaps have also been validated in several studies in reconstructive surgery [7,22]. However, some questions Fig.…”

Comparing Different Postconditioning Cycles After Ischemia Reperfusion Injury in the Rat Skin Flap

“…Up to this point, a few reports have been published to show the efficacy and mechanisms of IPOC on flap viability. 12,13 In these studies, after the end of 4 hours of ischemia, a cycle of 15 seconds of full reperfusion, followed by 15 seconds of complete reocclusion was repeated 6 times in the rat flap model. Results of our study demonstrated that the 30/30 and 60/60 seconds post-con groups resulted in better flap survival area than 15 seconds of IPOC protocols.…”

“…Since Zhao et al 7 first introduced the cardioprotective effect of post-con in a canine heart model, several reports have been published to show the efficacy and mechanisms of IPOC on flap viability. 12,13 The optimum protocol for post-con of skin flaps is still unknown, but it may involve more or fewer cycles and/or different time intervals. Because the threshold for ischemic tolerance of skin is higher than that of the myocardium, it is probable that skin require a different duration of post-con cycles than myocardium.…”

The Effect of Botulinum Toxin A on Ischemia-Reperfusion Injury in a Rat Model

“…The well-known NF-kB pathway transcribes many inflammatory molecules known to be associated with neutrophil accumulation. Inflammatory pathways, including the NF-kB pathway, are activated by ROS and are closely related to IR injury in skeletal muscles [35]. Although there was some thought that NF-kB activation could lead to a decrease in extracellular matrix degradation capacity, in turn leading to impaired angiogenesis [34], NF-kB transcription factors have been found to be effectors of the Rho family, including molecules such as the GTP-binding protein RAC1, during inflammation [19, 36].…”