茶氨酸对全脑缺血再灌注大鼠JNK信号通路与DNA修复的影响  

Effect of theanine on JNK signaling pathway and DNA repair in global brain ischemia/reperfusion rats

作　　者：王宁[1] 吕建瑞[1] 张珍妮[1] 薛荣亮[1] 

机构地区：[1]西安交通大学医学院第二附属医院麻醉科,西安710004

出　　处：《山西医科大学学报》2016年第5期415-418,454,共5页Journal of Shanxi Medical University

基　　金：国家自然科学基金资助项目(81071070)

摘　　要：目的探讨茶氨酸在大鼠全脑缺血再灌注过程中对c-Jun氨基末端激酶(c-Jun N-terminal kinases,JNK)信号通路与DNA修复的作用。方法 15周龄雄性SD大鼠108只,随机均分为假手术组(SH组)、缺血再灌注组(IR组)和茶氨酸组(TH组)。每组根据再灌注时间分为2,6,12,24,48,72 h 6个亚组,每亚组6只。采用4-VO法建立SD大鼠全脑缺血模型,在预定时间点行灌注固定取脑、石蜡包埋切片,光镜下计数CA1区存活细胞,TUNEL法检测CA1区凋亡细胞,免疫组化检测p-JNK和DNA修复蛋白X线修复交叉互补蛋白1(X-ray repair cross complementing protein l,XRCC1)的表达变化。结果脑缺血再灌注后海马CA1区神经元存活数目TH组明显高于IR组(P<0.01),凋亡细胞数目显著低于IR组(P<0.01)。海马CA1区p-JNK在IR组有明显表达,24 h达到高峰;TH组p-JNK的表达明显低于IR组(P<0.05)。SH组XRCC1表达量较强,IR组XRCC1的表达量下降(P<0.01)。TH组XRCC1表达量高于IR组(P<0.05)。结论在大鼠全脑缺血再灌注损伤过程中,JNK信号通路与DNA修复蛋白XRCC1有一定关联。JNK通路的激活在直接导致细胞损伤凋亡的同时,很可能也是DNA修复功能受伤的原因之一。茶氨酸则通过抑制JNK信号通路上调DNA修复蛋白XRCC1的表达发挥其神经保护作用。Objective To explore the effect of theanine on c-Jun N-terminal kinase（ JNK） signaling pathway and DNA repair in global brain ischemia / reperfusion rats. Methods One hundred and eight 15-week-old SD rats were randomly divided into sham operation group,ischemia-reperfusion（ IR） group and theanine group. Each group was divided into 6 subgroups according to reperfusion time：2,6,12,24,48,72 h groups. Transient global brain ischemia was induced by four-vessel occlusion,and the rats were perfusion-fixed at specified time points after reperfusion. The brains were removed,embedded and sliced up. The numbers of survival cells and apoptotic cells in hippocampal CA1 region were counted respectively by histochemistry and TUNEL,and the activities of p-JNK and X-ray repair cross complementing protein l（ XRCC1） were detected by immunohistochemistry. Results In theanine group,the number of survival cells in hippocampal CA1 region was significantly higher than that in IR group（ P〈0. 01）,and the number of apoptotic cells was lower than that in IR group（ P〈0. 01）. The p-JNK in IR group was markedly expressed in CA1 region,and the expression reached the peak at 24 h after reperfusion. The level of p-JNK in theanine group was significantly lower than that in IR group（ P〈0. 05）. The XRCC1 was markedly expressed in sham group,whereas the expression decreased in IR group（ P〈0. 01）,and the level of XRCC1 in theanine group was higher than that in IR group（ P〈0. 05）. Conclusion There is a certain relationship between JNK signaling pathway and DNA repair protein XRCC1 during global brain ischemia-reperfusion injury. The activation of the JNK signaling pathway may be one of the reasons of the damages of DNA repair protein function during the induction of cell apoptosis. Theanine may play its neuroprotection by inhibiting JNK signaling pathway and up-regulating the expression of DNA repair protein XRCC1.

关 键 词：脑缺血再灌注损伤 茶氨酸 细胞凋亡 C-JUN氨基末端激酶 DNA修复蛋白 

分 类 号：R363[医药卫生—病理学]