缺血预处理对家兔低位腹主动脉阻断后再灌注损伤的保护作用

The protective effects of ischemic precondition on lower abdominal aorta block and reperfusion in rabbits

目的研究缺血预处理对家兔低位腹主动脉阻断后再灌注损伤的保护作用。方法健康家兔24只，雌雄不拘，随机分为三组，每组8只。Ⅰ组：低位腹主动脉阻断2 h后开放；Ⅱ组：低位腹主动脉阻断3 h后开放；Ⅲ组：阻断腹主动脉5 min，开放10 min，重复3次后低位腹主动脉阻断3 h后开放。分别于阻断前（T1）、阻断后2 h（T2）、阻断后3 h（T3）、开放后2 h（T4）及开放后24 h（T5）抽取静脉血测定天冬酰胺转移酶（AST）、肌酸激酶（CK）、超氧化物歧化酶（superoxide dismutase，SOD）和丙二醛（malondialdehyde，MDA），并于开放后24 h观察动物后肢运动功能，处死家兔并留取股神经行电镜检查。结果所有动物均存活。T4、T5时，Ⅱ组和Ⅲ组CK、AST明显高于Ⅰ组（P〈0.05）；T1-T3时，各组SOD活性和MDA变化不明显，T4、T5时，各组SOD活性明显下降，MDA含量显著升高，Ⅱ组较Ⅰ组、Ⅲ组变化更明显（P〈0.05）；Ⅰ组和Ⅲ组动物术后后肢活动良好，Ⅱ组中有3只动物肌力差，其余未见明显异常；股神经电镜检查结果显示，Ⅰ组结构基本正常，Ⅲ组缺血性损害轻微，Ⅱ组最重。结论缺血预处理对腹主动脉阻断后再灌注损伤具有保护作用。

Objective To study the protective effects of ischemic precondition on lower abdominal aorta block and reperfusion in rabbits. Methods Twenty-four healthy rabbits regardless of sexes were randomly divided into three groups, each group containing 8 rabbits. Group Ⅰ ： reperfusion after 2 hours of lower abdominal aorta block;group Ⅱ ：reperfusion after 3 hours of lower abdominal aorta block;group Ⅲ ：5 mins block of lower abdominal aorta followed by 10 rains reperfusion, procedures were repeated three times, then blocked lower abdominal aorta for 3 hours and then did reperfusion. Venous blood samples were taken before lower abdominal aorta block（ T1 ） ,2 h（ T2 ） ,3 h（ T3 ） after block, and 2 h（T4 ） ,24 h（ T5 ） after reperfusion for determination of asparagine transferase （ AST ）, creatine kinase （ CK ）, superoxide dismutase （ SOD ） and malondialdehyde （MDA）. Motor functions of hind limbs were observed after reperfusion for 24 hours. All the animals were sacrificed and femoral nerves were removed for electron microscope examination. Results All animals survived. At T4 andT5, CK and AST in Group Ⅱ and Ⅲ were significantly higher than those in group Ⅰ （P 〈0.05）. T1 -T3, the activity of SOD and MDA in three groups did not change obviously, at T4 and TS, SOD activity decreased but MDA increased markedly. SOD and MDA of group Ⅱ changed more significantly than those of the other two groups （ P 〈 0.05 ）. In group Ⅰ and Ⅲ, postoperative hind limb movements of animals were almost normal, hind limb muscle strength deteriorated in three animals in group Ⅱ. Electron microscopic examination for femoral nerve showed that the nerve construction was basically normal in group Ⅰ , the ischemic lesion was minor in group HI, but that was the worst in group Ⅱ. Conclusion Ischemic preconditioning could have protective effects on lower abdominal aorta block and reperfusion.