不同方案缺血预处理对大鼠横形腹直肌肌皮瓣再灌注损伤的影响

目的 探讨不同方案缺血预处理（ischemic preconditioning，IPC）对大鼠横形腹直肌肌皮瓣（transverse rectus abdominis musculocutaneous flap，TRAM）移植后再灌注损伤的影响。方法选取雄性Wistar大鼠90只，建立TRAM模型，随机分为对照组和实验组，对照组10只，无需预处理过程，持续缺血4h后，恢复肌皮瓣血供；实验组分为8个亚组，每组10只，以微血管夹阻断腹壁下血管5min，再恢复血流5min，处理1次为sIPC5／5组，处理2次为bIPC5／5组，依次为sIPC5／10组（缺血5min／再灌注10min1次）、bIPC5／10组（缺血5min／再灌注10min2次）、sIPC10／5组（缺血10min／再灌注5min 1次）、bIPC 10／5组（缺血10min／再灌注5min2次）、sIPC10／10组（缺血10min／再灌注10min1次）、bIPC10／10组（缺血10min／再灌注10min2次），其余实验步骤与对照组相同；每组肌皮瓣恢复血供4h后，取3只处死取材，测定肌组织含水量及HE染色镜检观察骨骼肌组织结构，其余动物于术后第7天判断皮瓣成活情况，计算成活面积百分比。结果恢复血供12h后，各实验组肌皮瓣两侧边缘部分肿胀，色泽黯淡，较对照组肿胀范围小，程度轻；光镜下见各实验组肌纤维轻度肿胀，染色均一，肌纤维结构尚完整，胞核呈梭形，无明显肿胀。对照组肿胀明显，部分肌纤维断裂。各实验组与对照组相比肌组织水含量明显减少（P〈0．001），皮瓣成活面积提高了2～3倍（P〈0.001）。两次预处理对肌皮瓣成活面积的影响与相应的单次预处理比较，差异有统计学意义（P〈0．05）。结论IPC可明显减轻大鼠TRAM再灌注损伤程度，其保护效应受缺血／再灌注时间、处理次数等因素的影响。

EFFECTS OF DIFFERENT DURATIONS AND TIMES OF ISCHEMIC PRECONDITIONING ON ISCHEMIA-REPERFUSION INJURY TO TRAM FLAPS IN RATS

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. Conclusion 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.