亚甲蓝对兔肝缺血再灌注损伤的影响

Effect of methylene blue on liver ischemia-reperfusion injury in rabbits

目的 探讨亚甲蓝对兔肝缺血再灌注损伤的影响.方法 健康成年新西兰大白兔24只,雌雄不拘,体重2.0～2.3 kg,随机分为3组（n=8）：假手术组（S组）、肝缺血再灌注组（I/R组）和亚甲蓝组（MB组）.I/R组及MB组采用夹闭肝左外叶、中叶、右中叶及方形叶肝动脉分支40min再灌注60 min的方法制备肝缺血再灌注模型,S组仅游离相应血管.MB组于再灌注前20 min经耳缘静脉注射亚甲蓝5 mg/kg（用生理盐水稀释至5 ml）,S组及I/R组给予等容量生理盐水.于缺血前即刻（T1）、缺血20 min（T2）、加min（T3）、再灌注1 min（T4）、再灌注5 min（T5）、30 min（T6）、60 min（T7）时记录MAP和HR.于T1,5-7时取股动脉血样1 ml,测定血清TNF-α及IL-6的浓度.分别于T1,6,7时取股动脉血样1.5 ml,测定血浆ALT及AST的活性.于T7时测定肝左叶组织SOD活性及MDA含量,光镜下观察肝组织病理学结果.结果 与S组比较,I/R组T4-7,时MAP降低,T7时HR降低,肝组织SOD活性降低,MDA含量升高,I/R组及MB组T3-5时血清TNF-α和IL-6浓度升高,T6,7时血浆ALT和AST活性升高（P〈0.05或0.01）;与I/R组比较,MB组T4-7时MAP升高,肝组织SOD活性升高,MDA含量降低,T3-5时血清TNF-α和IL-6浓度降低,T6,7时血浆ALT和AST活性降低（P〈0.05或0.01）.MB组肝组织损伤较I/R组减轻.结论 亚甲蓝可维持血液动力学稳定,减轻兔肝缺血再灌注损伤.

Objective To investigate the effect of methylene blue（MB）on liver ischemia-reperfusion （I/R） injury in rabbits.Methods Twenty-four healthy New Zealand white rabbits of both sexes welshins 2.0-2.3 kg were randomly divided into 3 groups （n=8 each）：group Ⅰ sham operation（group s）;group Ⅱ I/R and group Ⅲ methylene blue （group MB）.The animals were anesthetized with intravenous 2% pentobarbital 30 mg/kg.Liver I/R was produced by occlusion of hepatic blood flow for 40 min followed by 60 min repeffusion.In group MB methylene blue 5 mg/kg was injected iv at 20 min before liver ischemia.Femoral artery was carmulated for MAP monitoring and blood sampling.MAP and HR were recorded immediately before（T1,baseline）and at 20 and 40 min of ischemia （T2,3） and 1,5,30,60 min（T4-7）of repedusion.Blood samples were collected at T1,T5,T6 and T7 for measurement of seruln TNF-α and IL-6 concentrations.Plasma AST and ALT activities were measured at T1,T6 and T7.Liver specimens were obtained at the end of experiment for determination of SOD activity and MDA content.Results In group I/R MAP was significantly decreased at T4-7 during reperfusion and HR at T7 as compared with the baseline at T1;while in group MB no significant change in MAP and HR Was observed during ischemia and reperfusion as compared with the baseline.The gerum TNF-α and IL-6 concentrations and the plasma ALT and AST activities were significantly increased during reperfusion as compared with the baseline immediately before ischemia in group I/R and MB and were significantly lower in group MB than in group. I/R. The SOD activity was significantly higher while MDA content was significantly lower in group MB than in group I/R. Microscopic examination showed that liver damage was less severe in group MB than in group I/R. Conclusion The administration of MB can maintain hemodynamic stability and attenuate liver I/R injury in rabbits.