血红素加氧酶-1在治疗性高碳酸血症减轻大鼠肝缺血-再灌注损伤中的作用

Role of HO-1 in reduction of hepatic ischemia-reperfusion injury by therapeutic hypercapnia in rats

目的探究血红素加氧酶-1(HO-1)在治疗性高碳酸血症减轻大鼠肝缺血-再灌注损伤中的作用。方法健康成年SD大鼠60只,随机均分为四组:假手术组(C组)、肝缺血-再灌注损伤组(IR组)、治疗性高碳酸血症处理组(A组)、治疗性高碳酸血症处理+锌原卟啉(ZnPP)预处理组(B组)。通过夹闭大鼠肝门静脉,肝动脉及胆管建立部分肝脏缺血-再灌注损伤模型,实验共缺血1h,再灌注6h。C组和IR组:实验全程机械通气吸入50%O2-50%N2;A组和B组:缺血即刻至再灌注结束期间吸入外源性50%O2-45%N2-5%CO2,C组、IR组、A组于实验前24h腹腔注射生理盐水5ml/kg,B组注射ZnPP 5mg/kg。于机械通气前(基础值)、缺血前即刻、再灌注即刻、再灌注后1、2、3、4、5、6h检测动脉血PaCO2;再灌注6h后取血清检测ALT、AST和TNF-α,并取肝组织HE染色观察病理学改变,TUNEL法检测细胞凋亡水平,Western blot法检测HO-1的相对量表达。结果与C组和IR组比较,A组和B组动脉血PaCO2水平明显升高(P<0.05)。与C组比较,IR组肝组织损伤严重,IR组、A组和B组血清ALT、AST和TNF-α含量、凋亡指数和A组HO-1相对表达量明显升高(P<0.05)。与IR组比较,A组肝组织损伤减轻,A组和B组血清ALT、AST、TNF-α含量、凋亡指数和B组的HO-1相对表达量明显降低(P<0.05),而A组HO-1相对表达量明显升高(P<0.05)。与A组比较,B组肝组织损伤加重,血清ALT、AST、TNF-α含量、凋亡指数明显升高(P<0.05),HO-1相对表达量明显下降(P<0.05)。结论治疗性高碳酸血症通过上调HO-1有效减轻肝缺血-再灌注损伤。

Objective To investigate the role of HO-1in reduction of hepatic ischemia-reperfnsion injury by therapeutic hypercapnia in rats.Methods Sixty male SD rats,weighing 240-260 g,were randomly divided into 4groups（n=15each）：sham operation group（group C）,hepatic ischemiareperfusion injury group（group IR）,therapeutic hypercapnia group（group A）,and ZnPP（CHE,a specific inhibitor of HO-1）group（group B）.The portal vein,hepatic artery and bile duct of the left lateral and median lobes of the liver were occluded for 1h,followed by 6hreperfusion in anesthetized rats.The rats inhaled 50%O2-50%N2 during mechanical ventilation in group C and group IR.In group A and group B,the rats inhaled 50%O2-45%N2-5%CO2during the whole study.Normal saline（5ml/kg）was injected intraperitoneally at 24 hbefore experiment in group C,IR and A,however,the rats was treated with ZnPP 5mg/kg in group B.Before mechanical ventilation（baseline）,immediately before ischemia,and at 0,1,2,3,4,5and 6hof reperfusion,the partial pressure of arterial carbon dioxide（PaCO2）was recorded from arterial blood samples that were obtained for blood gas analysis.At 6hof reperfusion,the serum aspartate amino transferase（AST）and alanine amino-transferase（ALT）activities and tumor necrosis factor-α（TNF-α）concentration（by ELISA）were determined.HE staining was used to observe the pathological changes of liver specimens,and TUNEL staining was used to detect the lever of cell apoptosis,detection the expression of HO-1by Western blot.Results Compared with group C and IR,PaCO2 in groups A and B were increased significantly（P〈0.05）.Compared with group C,pathological injury was more severe in group IR.The serum ALT,AST,TNF-αlevels and apoptosis index were increased significantly in group IR,group A,group B（P〈0.05）,the expression of HO-1was up-regulated in group A（P〈0.05）.Compared with group IR,pathological injury was less severe in group A.The serum ALT,AST,TNF-αlevels and apoptosis index were decreased significantly in group A,group B（P〈0.05）.The expression of HO-1was down-regulated in group B（P〈0.05）.Compared with group A,pathological injury was severe,and the serum ALT,AST,TNF-αlevels and apoptosis index were increased significantly（P〈0.05）.The expression of HO-1was down-regulated in group B（P〈0.05）.Conclusion Therapeutic hypercapnia can effectively alleviate the hepatic ischemia-reperfusion injury by up-regulating HO-1.