缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响

Effects of ischemic preconditioning-postconditioning on intestinal ischemia-reperfusion injury in rats

目的评价缺血预处理-后处理对大鼠肠缺血再灌注损伤的影响。方法清洁级成年雄性SD大鼠40只，体重225～275g，随机分为5组（n=8）：假手术组（S组）仅分离肠系膜上动脉（SMA），不夹闭；肠缺血再灌注组（IIR组）采用夹闭SMA60min，再灌注60min的方法制备肠缺血再灌注损伤模型；缺血预处理组（IPr组）夹闭SMA 10min，再灌注10min，余同IIR组；缺血后处理组（IPo组）夹闭SMA 60min后，再灌注30s，缺血30s，反复3次，再灌注60min；缺血预处理-后处理组（IPr-IPo组）先行缺血预处理，再行缺血后处理，操作过程同IPr组和IPo组。于再灌注60min时各组取肠粘膜组织，观察肠粘膜形态并行Chiu评分，检测丙二醛（MDA）含量，超氧化物歧化酶（SOD）及髓过氧化物酶（MPO）活性，同时采集动脉血样检测血浆肿瘤坏死因子α（TNF—α）及白细胞介素6（IL6）浓度。结果与S组比较，其余各组Chiu评分、MDA含量、MPO活性、血浆TNF—α与IL-6浓度升高，SOD活性降低（P〈0．05）。与IIR组比较，IPr组、IPo组及IPr-IPo组Chiu评分、MDA含量、MPO活性、血浆TNF-α和IL-6浓度降低，SOD活性升高（P〈0．01）。与IPr组和IPo组比较，IPr-IPo组Chiu评分和MDA含量降低，SOD活性升高（P〈0．05）。IPr组与IPo组各指标比较差异无统计学意义（P〉0．05）。结论缺血预处理-后处理可减轻大鼠肠缺血再灌注损伤，较单独应用时效果好。

Objective To evaluate the effects of ischemic preconditioning-postconditioning on the intestinal ischemia-reperfusion （IR） injury in rats. Methods Forty healthy male SD weighing 225-275 g were randomly assigned into 5 groups （n = 8 each）： group Ⅰ sham operation （group S）; group Ⅱ intestinal IR （group IIR）; group Ⅲ ischemic preconditioning （group IPr）; group Ⅳ ischemic postconditioning （group IPo）; group Ⅴ IPr ＋ IPo. The rats were anesthetized with intraperitonel 20% urethane 5 ml/kg. Superior mesenteric artery （SMA） was occluded for 60 min followed by 60 min reperfusion. In group S, SMA was isolated but not occluded. In group IPr, SMA was occluded for 10 min followed by 10 min reperfusion, and the rest procedures were performed using the method described in group IIR. In group IPo, 60 min ischemia was followed by three 30 s episodes of ischemia at 30 s intervals for reperfusion. In group IPr ＋ IPo, IPr was performed followed by IPo and the procedures were performed using the methods described in group IPr and IPo. The animals were killed at 60 miu of reperfusion. The intestinal tissues were immediately removed for determination of MDA content, SOD and MPO activities and the degree of damage to intestinal mucous membrane was scored according to Chiu score. Arterial blood samples were taken for determination of plasma concentrations of TNF-α and IL-6. Results Compared with group S, Chiu score, MDA content, MPO activity, and plasma concentrations of TNF-α and IL-6 were significantly increased, whereas SOD activity decreased in the other 4 groups （ P 〈 0.05） . Chiu score, MDA content, MPO activity, and plasma concentrations of TNF-α and IL-6 were significantly decreased, whereas SOD activity increased in group IPr, IPo and IPr ＋ IPo as compared with group IIR （ P 〈 0.05）. Chiu score and MDA content were significantly lower, whereas SOD activity higher in group IPr ＋ IPo than in group IPr and IPo （ P 〈 0.05）. No significant differences were detected in the indices between group IPr and group IPo （P 〉 0.05）. Conclusion Ischemic preconditioning-postconditioning can attenuate the intestinal IR injury in rats, and the efficacy is better than that of either IPr or IPo alone.