肢体缺血后处理与缺血预处理对孕兔失血性休克肝损伤保护作用的比较研究

A Comparative Study of Protective Effect of Limb Ischemia Postconditioning with Limb Ischemia Preconditioning on Liver Injury in Pregnant Rabbits with Hemorrhagic Shock

目的:比较肢体缺血后处理和肢体缺血预处理对孕兔失血性休克肝损伤保护作用的影响。方法:将32只孕兔随机分为4组:假手术组(S组)、缺血再灌注组(IR组)、肢体缺血后处理组(LRIP组)和肢体缺血预处理组(LIPC组),每组实验动物均行双侧股动脉游离。S组:只对双侧股动脉游离;IR组:孕兔股动脉放血,维持平均动脉压40 mm Hg 3 h后,1 h内匀速回输全部血液,使孕兔血压维持在MAP稳定在80 mm Hg之上并平稳24 h;LRIP组:孕兔股动脉放血3 h后,给予缺血后处理即夹闭双侧股动脉,进行10次缺血30 s再灌注30 s,再输血复苏至24 h。LIPC组:手术前24 h,重复3次采用压脉带捆扎兔单侧后肢5 min,直至后肢皮肤呈紫色、股动脉搏动消失、随后开放5 min,再行IR处理。24 h后观察血清中ALT、AST的变化,对肝组织MDA、SOD、NO及NOS的含量进行检测,ELISA法测定不同时点血清TNF-α、IL-10的含量,HE染色法进行肝组织病理学检查。结果:(1)与I/R组相比,LRIP组及LIPC组的肝组织SOD、NO、NOS含量则显著升高(P<0.01),而MDA含量明显降低(P<0.01);(2)血清TNF-α含量降低、IL-10含量升高;(3)同时肝组织病理形态学损伤亦明显减轻,而LRIP组与LIPC组相比无显著性差异(P>0.05)。结论:重复10次缺血30 s再灌注30 s的肢体后处理和手术前24 h重复3次对兔单侧后肢捆扎5 min、开放5 min缺血再灌注的肢体预处理,对肝脏功能具有保护作用,其机制可能与促进一氧化氮的生物学作用发挥保护效应、减少i NOS的表达、抑制再灌注后氧自由基的过量生成、改善肝脏内炎症反应有关。缺血后处理与缺血预处理对肝脏都有显著性的保护作用,但是彼此差异不显著。

objective： To compare the protective effect of the Limb ischemia post-processing with Limb ischemic preprocessing on liver injury in pregnant rabbits with hemorrhagic shock. Methods： 32 pregnant rabbits were randomly divided into 4 groups： sham operation group（ S）,ischemia reperfusion group（ IR）,limb remote ischemia post-processing group（ LRIP） and limb ischemic preconditioning group（ LIPC）. Each group of experimental animals was treated by bilateral femoral artery dissociation. S group was treated only by bilateral femoral artery dissociated. In IR group,the femoral arteries of the pregnant rabbits were bleeded. maintaining the mean arterial pressure 40 mm Hg for 3 hours,then all the blood lost were transfused back at a conctant speed within one hour. The blood pressure of pregnant rabbits was maintained at MAP,being above 80 mm Hg stable for 24 hours. In LRIP group,the femoral arteries of the pregnant rabbits were bleeded for 3 hours,given ischemia post-processing,which was clamping bilateral femoral artery,ischemia for 30 s and reperfusion for 30 s for 10 times,and recovered by blood transfusion for 24 hours. In LIPC group,24 hours before the surgery,the unilateral hind limbs of rabbits were tied up with the pressure pulse band for 5 min for 3 times until the skin of the hind legs was purple and the femoral artery pulse was disappeared. Subsequently the band was removed for 5minutes,then the IR processing was employed. 24 hours later,the change of ALT,AST in serum were observed; the content of MDA,NO,SOD and NOS of the hepatic tissue were detected; the contents of TNF-α and IL-10 in different points in serum were detected by ELISA method. Pathological examination of liver tissue were employ by HE staining method. Results：（ 1） Compared with IR group,the content of MDA,NO,SOD and NOS of the hepatic tissues of LRIP group and LIPC group were increased obviously（ P〈0. 01）,but the MDA contents obviously decreased（ P〈0. 01）;（ 2）In serum,TNF-α contents decreased and IL-10 contents increased;（ 3） At the same time,the pathological damages of liver tissue were significantly reduced,and there was no significant difference between LRIP group and LIPC group（ P〈0. 05）. Conclusion： To repeat 10 times 30 s reperfusion for 30 s for limb post-processing and to repeat it 3 times on unilateral hind limb of rabbits 24 hours before surgery,with being tied up for 5 minutes and being undone for 5 minutes in ischemia reperfusion for Limb preprocessing,have protective effect on liver function. The mechanism may be related to promoting biological effects of nitric oxide to play a protective effect,reducing the expression of i NOS,inhibiting excessive generation of oxygen free radicals after reperfusion,improving liver inflammation. Both the Ischemia postconditioninging and the Ischemia preconditioning have a significant protective effect,but the difference was not significant.