EPO干预后大鼠脑缺血再灌注区域STAT1和STAT3蛋白表达与细胞凋亡

Effects of erythropoietin on STAT1、STAT3 levels and apoptosis following cerebral ischemia-reperfusion in rats

目的研究促红细胞生成素(EPO)对大鼠局灶性脑缺血再灌注区域干预后STAT1、P-STAT1、STAT3、P-STAT3蛋白表达及细胞凋亡的影响。方法雄性SD大鼠120只,随机分为假手术组(A)、单纯脑缺血再灌注组(B)、脑缺血再灌注+生理盐水组(C)、脑缺血再灌注+EPO组(D),采用大脑中动脉线栓法制作大鼠局灶性脑缺血再灌注损伤模型。D组、C组分别于脑缺血刚开始时腹腔注射EPO或等量生理盐水,TTC染色观察大鼠脑缺血再灌注后脑梗死体积的变化,应用Western blot及免疫组织化学染色检测STAT1、P-STAT1、STAT3、P-STAT3蛋白表达水平的变化。采用末端转移酶介导的Dutp缺口末端标记法(TUNEL)检测神经细胞凋亡的变化。结果TTC显示EPO干预组脑梗死体积较未干预组明显缩小,STAT1、STAT3蛋白在正常脑组织中表达,且脑缺血再灌注及EPO干预对二者表达水平均无显著影响,而P-STAT1、P-STAT3在正常脑组织中表达较低,脑缺血再灌注后PSTAT1、P-STAT3蛋白表达增加。与B、C组比较,EPO干预后P-STAT3表达明显增加(P<0.05),P-STAT1有所减少(P>0.05),凋亡细胞数量较未干预组明显减少(P<0.05)。结论 EPO干预引发大鼠脑缺血再灌注区域PSTAT3表达的增加及P-STAT1表达的降低可能与神经细胞凋亡有关。

Objective To explore the effects of erythropoietin on STAT1 ,STAT3 levels and apoptosis following cere- bral ischemia-reperfusion in rats. Methods 120 male Sprague-Dawley rats were randomly divided into sham operation group （ A）, ischemia-reperfusion group （ B ）, ischemia-reperfusion group ＋ saline group （ C ）, ischemia-reperfusion group ＋ EPO group （D）, we established a rat focal cerebral ischemia-reperfusion injury model, at the beginning of cerebral ischemia, intraperitoneal injection of EPO was given to the EPO group, and an equivalent volume of saline was administered to group C. Tetrazolium chloride（TYC） staining assessed the infarct volume. Western blot and immunohistochemistry staining were used to observe STAT1 ,P-STAT1 ,STAT3 ,P-STAT3 expression, and TdT-mediated dUTP-biotin nick end-labeling（TUNEL） was employed to examine the cell apoptosis. Results In group D the infarct volume was significantly reduced（P 〈 0.05 ） compared to groups B and C. STAT1 and STAT3 proteins were expressed in normal brain tissue. Ischemia-reperfusion and EPO intervention had no significant effect on their expression. However,levels of P-STAT1 and P-STAT3 were low in normal brain tissue but altered after cerebral ischemia-reperfusion. Compared with groups B and C, P-STAT3 expression significant- ly increased（P 〈 0.05）, P-STAT1 expression decreased（ P 〉 0.05） and the number of apoptotic cells in group D was sig- nificantly reduced （P 〈 0.05）. Conclusion After EPO treatment the increased expression of P-STAT3 and the decreased expression of P-STAT1 may be involved in the ischemic cellulars events including apoptosis.