Wnt/β-catenin信号通路介导参麦注射液对脑缺血再灌注损伤大鼠的脑保护作用

Wnt/β-catenin signaling pathway mediates the protective effect of Shenmai injection on cerebral ischemia-reperfusion injury in rats

目的 观察Wnt/β-catenin信号通路是否介导参麦注射液（SM）对脑缺血再灌注损伤（CIRI）大鼠的脑保护作用。方法 84只SD大鼠按随机区组的方法分成7组：假手术组（Sham）、模型组（MCAO）、参麦注射液＋模型组（SM＋MCAO）、生理盐水（NS）＋模型组（NS＋MCAO）、磷酸盐缓冲液（PBS）＋参麦注射液＋模型组（PBS＋SM＋MCAO）、Wnt/β-catenin拮抗剂Dickkopf-1（Dkk-1）＋参麦注射液＋模型组（Dkk-1＋SM＋MCAO）、Dkk-1＋模型组（Dkk-1＋MCAO）,每组12只。采用线栓大脑中动脉阻塞（MCAO）法建立大鼠CIRI模型。在脑缺血即刻,SM＋MCAO组、PBS＋SM＋MCAO组、Dkk-1＋SM＋MCAO组大鼠腹腔注射参麦注射液（15 mL/kg）,NS＋MCAO组大鼠注射等量生理盐水。Dkk-1＋SM＋MCAO组、Dkk-1＋MCAO组大鼠分别在建立模型前30 min脑室注射Dkk-1（1 g/L,1μL）,PBS＋SM＋MCAO组大鼠脑室注射等量PBS。再灌注24 h,评估各组大鼠神经行为学评分,检测脑梗死体积以及脑梗死半暗带区Bcl-2、Bax和β-catenin蛋白表达量,并计算Bcl-2/Bax比率。结果 与假手术组相比,MCAO组大鼠神经行为学评分、脑梗死体积、Bcl-2和Bax以及β-catenin蛋白表达量均增加（P〈0.05）,而Bcl-2/Bax比率减小（P〈0.05）;与MCAO组相比,SM＋MCAO组大鼠神经行为学评分、脑梗死体积以及Bax蛋白表达量明显减少（P〈0.05）,Bcl-2和β-catenin蛋白表达量以及Bcl-2/Bax比率明显增加（P〈0.05）;与SM＋MCAO组相比,Dkk-1＋SM＋MCAO组大鼠神经行为学评分、脑梗死体积、Bax蛋白表达量明显增加（P〈0.05）,而Bcl-2蛋白表达量、Bcl-2/Bax比率明显减小（P〈0.05）。结论 参麦注射液通过上调Wnt/β-catenin信号通路改善CIRI大鼠的脑损伤。

Aim To observe whether the Wnt/β-catenin signaling pathway mediates the protective effect of Shenmai injection （SM） on cerebral ischemia-reperfusion injury （CIRI） in rats. Methods According to the randomized block principle, 84 SD rats were divided into 7 groups： sham operation group （sham）, model group （MCAO）, SM＋ model group （ SM＋MCAO）, normal saline （NS） ＋model group （ NS＋MCAO）, phosphate buffered solution （PBS） ＋SM＋ model group （ PBS ＋ SM ＋ MCAO ）, Wnt/β-catenin antagonist dickkopf-1 （ Dkk-1 ） ＋ SM ＋ model group （ Dkk-1 ＋ SM ＋MCAO）, Dkk-l＋model group （Dkk-I＋MCAO）, 12 rats in each group. Rat CIRI model was established by middle cere- bral artery occlusion （MCAO） with line embolus. Immediately after cerebral ischemia, SM＋MCAO group, PBS＋SM＋ MCAO group and Dkk-I＋SM＋MCAO group were intraperitoneally injected with SM （15 mL/kg） , whereas NS＋MCAO group was injected with equal amount of NS. At 30 min before the model was set up, Dkk-I＋SM＋MCAO group and Dkk-1＋MCAO group were injected with Dkk-1 （ 1 g/L, 1 μL） to the ventricle, whereas PBS＋SM＋MCAO group was injected with equal amount of PBS. After reperfusion for 24 h, neurobehavioral score was assessed in each group, cerebral infarction volume was measured, expressions of Bcl-2, Bax and β-catenin protein were detected in the semi-dark zone of cerebral infarction, and Bcl-2/Bax ratio was calculated. Results Compared with the sham group, neurobehavioral score, cere- bral infarction volume, and the expressions of Bcl-2, Bax, and β-catenin proteins were increased in the MCAO group （ P〈 0.05）, and Bcl-2/Bax ratio was reduced （P〈0.05）. Compared with the MCAO group, neurobehavioral score, cerebral infarction volume and Bax protein expression were significantly reduced in the SM ＋ MCAO group （P 〈0. 05 ）, the expressions of Bcl-2 and 13catenin proteins and Bcl-2/Bax ratio were significantly increased （P〈 0.05）. Compared with the SM＋MCAO group, neurobehavioral score, cerebral infarction volume and Bax protein expression were significantly increased in the Dkk-I＋SM＋MCAO group （P〈0.05）, while Bcl-2 protein expression and Bcl-2/Bax ratio were significantly decreased （P〈0.05）. Conclusion Shenmai injection improves brain damage of CIRI rat by up-regulation of Wnt/β- catenin signaling pathway.