MAPK信号转导通路中ERK、JNK和P38在大鼠肝脏缺血再灌注和缺血后处理中表达的变化

Changes of ERK,JNK,and P38 in MAPK signal transduction pathway following hepatic ischemia-reperfusion and ischemic postconditioning in rats

背景:近年来,随着器官移植的不断开展和深入研究,人们逐渐认识到供肝原发性无功能是引起肝移植患者早期死亡的主要原因,而缺血再灌注损伤是导致供肝功能不良的重要因素。如何减轻或消除缺血再灌注损伤一直是临床研究的热点。目的:观察肝缺血再灌注损伤和缺血后处理后MAPK级联通路中P38,JNK和ERK活化的情况。设计、时间及地点:随机对照动物实验,于2007-05/10在中南大学湘雅医院动物实验中心完成。材料:102只Wistar大鼠随机分为假手术组6只,缺血30min再灌注组48只和缺血后处理组48只,后2组又分为0,0.5,1,2,4,8,12,24h不同时间处理亚组,每亚组6只。方法:建立大鼠肝脏体内局部缺血再灌注-缺血后处理模型,于复灌后0,0.5,1,2,4,8,12,24h取肝脏组织。主要观察指标:应用免疫组织化学的方法对磷酸化的p-P38、p-JNK和p-ERK进行免疫组化检测并作半定量分析。结果:①p-ERK,p-JNK在缺血后即有轻度增高,但在再灌注后30min开始增高明显,持续到再灌注后4h,高峰出现在再灌注后2h。缺血后处理组p-ERK,p-JNK的表达在再灌注后1,2,4h较缺血再灌注组增高(P<0.05)。②p-P38在缺血后即有轻度地增高,但在再灌注后30min开始增高明显,高峰出现在再灌注后1h,2h后开始下降,表达程度维持在缺血后水平。与缺血再灌注组相比,缺血后处理组p-P38的表达增高,但仅在再灌注后1h明显增高(P<0.05)。结论:缺血后处理可通过增高ERK和P38的磷酸化水平,降低JNK的磷酸化水平减轻缺血再灌注导致的肝脏损伤。

BACKGROUND： Recently research demonstrated that primary non function of transplanted hepar is the main reason for early death after hepatic transplantation, so as to ischemia-reperfusion injury for poor graft function. How to relieve or eliminate the ischemia-reperfusion injury is the hot topic in clinic research. OBJECTIVE： To observe the expression of ERK, JNK, and P38 in MAPK signal transduction pathway of hepatic ischemia-reperfusion injury and hepatic ischemic postconditioning settings. DESIGN, TIME AND SETTING： The randomized controlled experiment of animals was performed in the Experimental Animal Center of Affiliated Xiangya Hospital of Central South University from May to October 2007. MATERIALS： A total of 102 Wistar rats were randomly divided into the sham operation （n=6）, ischemia-reperfusion （n=48） and ischemic postconditioning （n=48） groups. The animals in the ischemia-reperfusion and ischemic postconditioning groups were assigned into subgroups treated with various time （0, 0.5, 1, 2, 4, 8, 12, 24 hours）, with 6 animals in each subgroup. METHODS： The orthotopic partial hepatic ischemia-reperfusion injury animal model was used. 120 Wistar rats were randomly divided into ischemia reperfusion, ischemic postconditioning and sham operation groups. Liver tissues were harvested at 0, 0.5, 1, 2 4, 8, 12 and 24 hours after reperfusion. MAIN OUTCOME MEASURES： The phosphorylation P38, JNK and ERK were detected by immunohistochemistry and semi-quantitative analysis. RESULTS： p-ERK and p-JNK increased slightly after ischemia, increased significantly at 30 minutes until 4 hours, peaked at 2 hours after repen^usion. Compared with the ischemia reperfusion group, the expression of p-ERK, p-JNK in the treated group was higher than that of the ischemia reperfusion group at 1, 2 and 4 hours after reperfusion （P 〈 0.05）. The expression of p-P38 increased slightly after ischemia, significant increased at 30 minutes, peaked at 1 hour, and then decreased at 2 hours after reperfusion, which remained a ischemia level. Compared with the ischemia reperfusion group, the expression of p-P38 in the treated group was higher, in particular, at 1 hour after reperfusion （P 〈 0.05）. CONCLUSION： The ischemia preconditioning can relieve the liver injury in ischemia-reperfusion by increase the levels of ERK, P38 and decrease JNK phosphorylation level.