肢体缺血预处理对大鼠肝缺血再灌注诱发肠损伤和脑损伤的影响

Effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic is-chemia-reperfusion in rats

目的评价肢体缺血预处理对大鼠肝缺血再灌注诱发肠损伤和脑损伤的影响。 方法健康雄性Wistar大鼠48只，6～8周龄，体重200～250 g，采用随机数字表法分为3组（n＝16）：假手术组（Sham组）、肝缺血再灌注组（I/R组）和肢体缺血预处理组（LIP组）。LIP组右侧腹股沟处以弹力橡皮止血带环形捆扎阻断下肢血流10 min时，松开止血带恢复灌注30 min。然后I/R组和LIP组采用Pringle法阻断门静脉、肝动脉及胆总管30 min后恢复灌注的方法制备肝缺血再灌注损伤模型。再灌注6 h时，每组取8只大鼠，心尖取血样采用放免法检测血浆TNF-α和IL-10的浓度，然后处死大鼠，取小肠组织和脑组织，采用Chiu评分法评价肠黏膜损伤程度，采用比色法测定肠粘膜髓过氧化物酶（MPO）活性，光镜下观察脑组织病理学结果，电镜下观察脑组织超微结构。再灌注6 h时，每组取8只大鼠，经1 min尾静脉注射伊文氏蓝（EB）2 mg/kg，处死取脑组织，测定EB含量，计算含水率。 结果与Sham组比较，I/R组和LIP组肠黏膜Chiu评分和肠组织MPO活性升高，脑组织含水率和EB含量升高，血浆TNF-α和IL-10的浓度升高（P〈0.05）；与I/R组比较，LIP组肠黏膜Chiu评分和肠组织MPO活性降低，脑组织含水率和EB含量降低，血浆IL-10浓度升高（P〈0.05），血浆TNF-α浓度差异无统计学意义（P〉0.05），脑组织病理学损伤减轻。 结论肢体缺血预处理可减轻大鼠肝缺血再灌注诱发肠损伤和脑损伤，其机制可能与抑制全身炎症反应有关。

Objective To evaluate the effects of limb ischemic preconditioning on intestinal injury and brain injury induced by hepatic ischemia-reperfusion （I/R） in rats. Methods Healthy male Wistar rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups （n= 16 each） using a random number table ： sham operation group （ Sham group）, hepatic I/R group （ I/R group） and limb ischemic preconditioning group （LIP group）. In LIP group, the lower limb blood flow was blocked for 10 rain with an elastic rubber tourniquet at the right groin followed by 30-min reperfusion through releasing the tourni- quet. Hepatic I/R injury was induced by occlusion of the portal vein, hepatic artery and common bile duct for 30 min followed by reperfusion in I/R and LIP groups. Eight rats in each group were selected at 6 h of reperfusion and samples from the cardiac apex were taken for determination of plasma concentrations of tumor necrosis factor-alpha （TNF-a） and interleukin-10 （IL-10） by radioimmunoassay. Then the rats were sacrificed and the small intestine tissues and brain tissues were removed. Intestinal damage was as-sessed and scored according to Chiu. The activity of myeloperoxidase （MPO） in intestinal mucosa was de- tected by colorimetric method. The pathological changes of brain tissues were examined under a light micro- scope. The uhrastructure of brain tissues was observed under an electron microscope. Eight rats in each group were randomly selected at 6 h of reperfusion, and Evans blue （EB） 2 mg/kg was injected through the caudal vein over 1 rain. Then the rats were sacrificed, brain tissues were removed for measurement of EB content, and the brain water content was calculated. Results Compared with Sham group, Chiu＇s score and MPO activity in intestinal tissues were significantly increased, the brain water content and EB content were increased, and the concentrations of TNF-a and IL-10 in plasma were increased in I/R group and LIP group （P 〈0. 05）. Compared with I/R group, Chiu＇s score and MPO activity in intestinal tissues were significantly decreased, the brain water content and EB content were decreased, and plasma IL-10 concentrations were increased （P 〈0. 05）, no significant change was found in plasma TNF-aconcentra- tions （P〉0. 05）, and the pathological ＇changes of brain tissues were significantly attenuated in LIP group. Conclusion Limb ischemic preconditioning can attenuate intestinal injury and brain injury induced by he- patic I/R, and the mechanism may be related to inhibiting systemic inflammatory responses of rats.