一氧化氮在缺血预处理保护大鼠移植肝脏再灌注损伤中的作用

目的　探讨一氧化氮 (NO)在缺血预处理 (IP)保护大鼠移植肝脏缺血再灌注损伤中的作用。方法　采用SD大鼠原位肝移植动物模型 ,供肝冷保存时间为 10 0min ,无肝期 2 5min。12 8只大鼠随机分成 4组 (n =32 ) :A组 (对照组 )、B组 (IP组 )、C组 [腺苷 (Ade)组 ]、D组 [NO合成抑制剂N L 精氨酸甲基脂 (NAME)组 ]。其中各组的半数用于观察存活率 ,另一半用于移植肝脏再灌注 2h后取血及肝脏检测。结果　IP组和Ade组的 1周存活率、胆汁分泌量、抗氧化酶活力及血清NO水平均明显高于对照组 (P <0 .0 5 ) ,血清丙氨酸氨基转移酶 (ALT)、肿瘤坏死因子(TNF)及肝组织中的过氧化物含量均明显低于对照组 (P <0 .0 5 )。肝组织损伤以窦状内皮细胞为主 ,并且是以凋亡的方式发生死亡 ,IP组和Ade组窦状内皮细胞损伤明显轻于对照组 (P <0 .0 0 1) ;NAME组的各种观察结果与对照组相近 (P >0 .0 5 )。结论　IP能够通过增加NO的合成来减轻再灌注早期窦状内皮细胞所受到的损伤 ,改善微循环 ,提高移植肝脏的功能。

Protective effect of nitric oxide induced by ischemic preconditioning on reperfusion injury of rat liver graft

Objective To investigate the protective e ffect of nitric oxide (NO) induced by ischemic preconditioning (IP) on ischemic reperfusion injury of rat liver graft.Methods Male Spragu e Dawley rats were used as donors and recipients of orthotopic liver transplanta tion,and the period of cold preservation and anhepatic phase were 100 min and 2 5 min respectively.128 rats were randomly divided into 4 groups (n=32):gro up A (control group),donor livers were flushed through the portal veins with no rmal saline containing heparin only before harvested;group B (IP group),before donor livers were harvested,the portal veins and hepatic arteries of them were interrupted for 10 min,and reflow was initiated for another 10 min,then did a s control group;group C (Adenosine,Ade group),donor livers were flushed throu gh the portal veins with normal saline containing heparin and Ade (10 mmol/L) on ly before harvested;group D (inhabitor of NO synthesis,NAME group),donor live rs were treated as IP group,except NAME (10 mmol/L) was added into flushing sol ution.One half of each group were used to investigate 0ne week survival rate of recipients,and another half of each group were used to take sample of blood an d hepatic tissue after 2 h reperfusion of liver graft.Results Z One week survival rate,amount of bile flow,serum NO and activity of anti -oxidase levels were higher in IP group and Ade group than those in control gro up (P<0.05),meanwhile,serum ALT,TNF and superoxide levels in hepatic ti ssue were lower in IP group and Ade group than those in control group (P<0. 05).Sinusoidal endothelial cells were the principal target of reperfusion inju ry and their deaths were caused by apoptosis.Sinusoidal endothelial cells in IP group and Ade group showed less injury than those in control group (P<0.05 ).All findings in NAME group showed similar results to those in control group (P>0.05).Conclusion Through the stimulation of endo genous NO,IP could protect sinusoidal endothelial cells from injury during the early phase of reperfusion and improve the microcirculation and function of rat liver graft.