Yan Hede, Zhang Feng, Kochevar Andrew J, Akdemir Ovunc, Gao Weiyang, Angel Michael
Division of Plastic Surgery, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
J Invest Surg. 2010 Oct;23(5):249-56. doi: 10.3109/08941931003615529.
Timely recognition of vascular compromise of free flaps is crucial to salvaging failing flaps due to the vulnerability of muscle tissues to ischemia. The concept of postconditioning (post-con) that has been introduced as an “after injury" strategy may be beneficial to salvage the failing muscle flaps. We aim to investigate the effect of post-con on the muscle flap survival after ischemia-reperfusion (I/R) injury in rats.
The gracilis muscle flap model was used and a complete 4 hr of ischemia was generated by occlusion of the pedicle of dissected flap. The post-con procedure was started at the end of ischemia with six cycles of 15 s of reperfusion, followed by 15 s of complete reocclusion prior to the unlimited reperfusion. Muscle edema, malondialdehyde (MDA) level, muscle viability, and different time intervals (0, 3, 6, 18 hr) of gene expression of VEGF post-perfusion were assessed.
Significant difference in muscle viability was noted between the post-con group and the control group (4 hr of ischemia followed by full reperfusion without intervention) in spite of being noncomparable with the sham group (no ischemic exposure) 3 days postoperatively. Statistically decreased muscle edema and MDA level were observed in the post-con group compared with the control group. Histological study also showed that attenuated inflammatory reaction was observed in the post-con group compared with the control group. A relatively higher level of VEGF since 3-hr post-reperfusion in the post-con group compared with the control and sham groups was recorded.
Our results indicate that post-con procedure effectively reduces I/R injury and improves the survival of muscle flaps after ischemia. The consistent expression of VEGF in a high level may play an important role in the physiological effects of post-con.
由于肌肉组织对缺血的脆弱性，及时识别游离皮瓣的血管受损对于挽救失败的皮瓣至关重要。作为一种“损伤后”策略引入的后处理（post-con）概念可能有助于挽救失败的肌肉皮瓣。我们旨在研究后处理对大鼠缺血再灌注（I/R）损伤后肌肉皮瓣存活的影响。
采用股薄肌皮瓣模型，通过阻断解剖皮瓣的蒂部造成4小时的完全缺血。后处理程序在缺血结束时开始，进行6个周期，每个周期包括15秒的再灌注，然后在无限制再灌注之前进行15秒的完全再闭塞。评估肌肉水肿、丙二醛（MDA）水平、肌肉活力以及灌注后不同时间间隔（0、3、6、18小时）的血管内皮生长因子（VEGF）基因表达。
尽管术后3天与假手术组（无缺血暴露）无可比性，但后处理组与对照组（4小时缺血后不干预直接完全再灌注）之间在肌肉活力方面存在显著差异。与对照组相比，后处理组的肌肉水肿和MDA水平在统计学上有所降低。组织学研究还表明，与对照组相比，后处理组观察到炎症反应减弱。与对照组和假手术组相比，后处理组在再灌注后3小时起VEGF水平相对较高。
我们的结果表明，后处理程序可有效减轻I/R损伤并提高缺血后肌肉皮瓣的存活率。VEGF的持续高水平表达可能在后处理的生理效应中起重要作用。
