AMP激活的蛋白激酶对大鼠弥漫性轴索损伤后神经元自噬的调节
Role of AMP-activated protein kinase in neuronal autophagy after diffuse axonal injury in rats

摘要：目的 研究AMP激活的蛋白激酶(AMPK)信号通路在弥漫性轴索损伤(DAI)大鼠脑组织中的表达，探讨AMPK对DAI后神经自噬的调节机制。方法 大鼠头颅瞬间旋转损伤法建立DAI模型，免疫蛋白印迹法检测造模后1、3、7d大脑皮层和海马AMPK、磷酸化AMPK(p-AMPK)、Beclin1、LC3Ⅰ/Ⅱ、p62蛋白的动态表达，并与正常组和假手术组比较。侧脑室给予AMPK抑制剂Compound C及激活剂AICAR，检测药物干预对大鼠神经自噬相关蛋白表达的影响，并与DAI组和vehicle组进行比较。结果 与正常组和假手术组相比，DAI 1d后脑内AMPK信号通路激活，3d后脑内自噬水平上调；Compound C可以减少AMPK磷酸化激活同时下调脑内的自噬水平，AICAR可以增高AMPK磷酸化水平上调神经自噬改善神经功能损伤。结论 大鼠DAI后AMPK的激活可以上调神经自噬的水平，对DAI后的神经保护有重要意义。
ABSTRACT: Objective To investigate the activation of AMP-activated protein kinase (AMPK) in the cerebral cortex and the hippocampus after diffuse axonal injury (DAI) so as to explore the role of AMPK in neuronal autophagy after DAI. Methods Rat diffuse axonal injury was induced by a new experimental facility, which was developed to make the rat head spin 90 degrees at the moment to cause shearing injury. Western blot was used to detect the protein levels of phosphorylated AMPK and autophagy-related protein (Beclin1, LC3 I/Ⅱ, p62) in the cerebral cortex and the hippocampus. After AICAR and Compound C were administered by intraventricular injection, the change of p-AMPK level was examined, and the effects of AICAR and Compound C on neurological behavior and the expression of Beclin1 were observed. Results Compared with those in normal group and sham-operation group, the expression of phosphorylated AMPK and the level of neural autophagy were up-regulated sharply after DAI; AICAR administration facilitated neuronal autophagy and ameliorated neurological deficit through upregulating phosphorylated AMPK. In contrast, Compound C treatment downregulated the phosphorylated level of AMPK and the expression of Beclin1. Conclusion The activation of AMPK up-regulates the level of neural autophagy, which is important to neural protection after DAI