Ferencz A, Rácz B, Gasz B, Kalmár-Nagy K, Horváth O P, Röth E
Department of Surgical Research and Techniques, University of Pécs Medical School, Kodály Zoltán Street 20, Pécs, H-7624 Hungary.
Transplant Proc. 2006 Jul-Aug;38(6):1800-2. doi: 10.1016/j.transproceed.2006.05.014.
Ischemic preconditioning (IPC), which is obtained by exposure to brief periods of vascular occlusion, improves organ tolerance to prolonged ischemia. The aim of this study was to evaluate the threshold level of NF-kB activation in small intestine during an IPC procedure. Various intestinal IPC were performed on 20 Wistar rats in seven groups: group I (GI, nonpreconditioned); group II (GII, 1-minute ischemia and 1-minute reperfusion); group III (GIII, two cycles of 1-minute ischemia and 1-minute reperfusion); group IV (GIV, 2-minutes ischemia and 2-minutes reperfusion); group V (GV, two cycles of 2-minute ischemia and 2-minute reperfusion); group VI (GVI, 5-minute ischemia and 10-minute reperfusion); group VII (GVII, two cycles of 5-minute ischemia and 10-minute reperfusion). Bowel biopsies were collected after laparotomy (control) as well as at 30, 60, and 120 minutes following IPC. We determined the cytoplasmic and nuclear NF-kB by a chemiluminescence-based ELISA method. Our results showed low, constant NF-kB levels in GI. In the preconditioned groups (GII-GVII), NF-kB was significantly elevated at 30 minutes following IPC (P < .05 vs control). After 1 hour, NF-kB activity decreased to the control level. However, 2 hours after IPC both forms of NF-kB were elevated significantly again, which was independent of the number of IPC cycles (P < .05 vs control). Our experiments revealed that one cycle of 1-minute ischemia and 1-minute reperfusion is a critical threshold level for NF-kB activation during small bowel IPC. Longer and more IPC cycles did not result in further elevation of NF-kB activation.
缺血预处理（IPC）通过短暂的血管闭塞获得，可提高器官对长时间缺血的耐受性。本研究的目的是评估缺血预处理过程中小肠中NF-κB激活的阈值水平。对20只Wistar大鼠进行了七组不同的肠缺血预处理：第一组（GI，未预处理）；第二组（GII，1分钟缺血和1分钟再灌注）；第三组（GIII，两个周期的1分钟缺血和1分钟再灌注）；第四组（GIV，2分钟缺血和2分钟再灌注）；第五组（GV，两个周期的2分钟缺血和2分钟再灌注）；第六组（GVI，5分钟缺血和10分钟再灌注）；第七组（GVII，两个周期的5分钟缺血和10分钟再灌注）。剖腹术后（对照）以及缺血预处理后30、60和120分钟采集肠活检组织。我们通过基于化学发光的ELISA方法测定细胞质和细胞核中的NF-κB。我们的结果显示GI组中NF-κB水平低且恒定。在预处理组（GII - GVII）中，缺血预处理后30分钟NF-κB显著升高（与对照组相比P <.05）。1小时后，NF-κB活性降至对照水平。然而，缺血预处理2小时后，两种形式的NF-κB再次显著升高，这与缺血预处理周期数无关（与对照组相比P <.05）。我们的实验表明，1分钟缺血和1分钟再灌注的一个周期是小肠缺血预处理过程中NF-κB激活的关键阈值水平。更长时间和更多的缺血预处理周期并未导致NF-κB激活的进一步升高。
