不同预处理对肝硬化兔缺血再灌注肝组织HSP70及ET-1表达的影响

Effects of two different preconditioning methods on expression of ET-1 and HSP70 in liver tissues of rabbits with cirrhosis after ischemia/reperfusion

目的:探讨两种预处理方式,即经典缺血预处理(IPC)与肢体缺血预处理(LIPC),对肝硬化兔肝缺血再灌注(I/R)损伤的保护作用及可能的作用机制。方法:皮下注射CCl4-橄榄油溶液制备兔肝硬化模型,随后将模型兔随机分为假手术组,肝I/R组(I/R组),IPC+肝I/R组(IPC组),LIPC+肝I/R组(LIPC组),每组7只。肝I/R模型制作方法:阻断入肝血流30 min,再灌注2 h;IPC诱导方法:在行肝I/R处理前阻断入肝血流10 min,开放10 min;LIPC诱导方法:在行肝I/R处理前24 h,采用止血带捆扎兔单侧后肢5 min,再开放5 min,重复3次。各组于再灌注2 h后切取肝组织,行组织形态学观察,用ELISA法测定内皮素1(ET-1)含量及Western blot法检测热休克蛋白(HSP70)的表达。结果:与假手术组比较,其余各组在肝硬化病变的基础上均出现不同程度的变性、水肿和炎性细胞浸润,但IPC组与LIPC组明显轻于I/R组,而LIPC组及IPC组间病变程度无明显差异;与假手术组比较,其余各组肝组织ET-1含量和HSP70的表达均明显增加(均P<0.05),但IPC组与LIPC组肝组织ET-1含量低于I/R组,HSP70的表达高于I/R组(均P<0.05),而上述2项指标在LIPC及IPC组间均无统计学差异(均P>0.05)。结论:LIPC和IPC均能对肝硬化肝I/R损伤有保护作用,且保护强度相似,其机制可能均与抑制ET-1的释放及增加HSP70的表达有关;LIPC具有无创性,可能具有更大的临床应用前景。

Objective： To investigate the protective effects of two different preconditioning methods,namely the classical ischemic preconditioning（IPC） and limb ischemic preconditioning（LIPC）,on liver ischemia/reperfusion injury in rabbits with cirrhosis and their possible mechanisms. Methods： Rabbit model of liver cirrhosis was induced by subcutaneous injection of CCl4-olive oil solution.Subsequently,the cirrhotic rabbits were randomly divided into the sham operation group,hepatic I/R group（I/R group）,IPC ＋ hepatic I/R group（IPC group） and LIPC ＋ hepatic I/R group（LIPC group）,with 7 rabbits in each group.The hepatic I/R model was produced by occlusion of hepatic inflow for 30 min and then reperfusion for 2 h,IPC was induced by a 10-min hepatic occlusion and 10-min reperfusion just before I/R procedure,and LIPC was elicited by 3 cycles of 5-min occlusion and 5-min reperfusion of the unilateral hind limb using a tourniquet 24 h before I/R.The liver samples of each group were obtained after 2-h reperfusion,then histopathological examination was performed,and level of endotholin 1（ET-1） and expression of heat shock protein 70（HSP70） in the liver tissues were detected by ELISA and Western blot,respectively. Results： Compared with sham operation group,all other groups presented degeneration,hydrops and inflammatory cell infiltration of varying degrees on the basis of cirrhosis,but these pathological changes in both IPC and LIPC groups were obviously milder than those in I/R group,and were similar between IPC and LIPC group.Compared with sham operation group,the ET-1 levels and HSP70 expressions in liver tissues of other groups all significantly increased（all P0.05）,but in both IPC and LIPC groups,the ET-1 levels were significantly lower and the HSP70 expression were significantly higher than that in I/R group（all P0.05）,while these two indexes had no significant differences between IPC and LIPC group（both P0.05）. Conclusion： Both LIPC and IPC have protective effect against I/R injury of the cirrhotic liver.There is no significant difference in the protective intensity of the 2 methods.LIPC may have a high potential for clinical application because of its non-invasiveness