臂丛神经损伤后脊髓神经元脑衰反应调节蛋白2表达上调以加快轴突生长

Increased collapsin response mediator protein 2 in spinal cord neurons promotes axon regeneration after brachial plexus injury

目的观察臂丛神经损伤后大鼠脊髓中脑衰反应调节蛋白2(CRMP2)的表达及其作用。方法构建臂丛撕脱伤大鼠模型,收集损伤后1、3、7、10d大鼠脊髓标本,使用实时定量反转录聚合酶链反应(RT-qPCR)及Westernblot方法检测CRMP2的表达变化及磷酸化水平。使用免疫荧光法检测CRMP2在脊髓中的空间表达。在体外培养的神经元中观察调控CRMP2表达对神经元突起生长的影响。结果在臂丛撕脱伤后第1、3、7、10天,RT-qPCR及Westernblot法检测均显示脊髓中CRMP2表达明显增加。Westernblot法检测显示术后第3、7天实验组磷酸化CRMP2的表达量为0.154±0.113、0.124±0.200,Sham组磷酸化CRMP2表达量为0.342±0.200、0.434±0.165。实验组较Sham组磷酸化水平明显降低。CRMP2表达于脊髓神经元中,在小胶质细胞及星型胶质细胞中未观察到其表达。在体外培养的神经元中调控CRMP2表达,测得神经元的轴突长度及突起数目在上调组为7.066±1.762、24.500±8.816,下调组为1.044±0.556、8.000±3.295。上调组较下调组明显增加。结论臂丛神经损伤后,脊髓神经元CRMP2表达增加能够加快神经轴突生长,对神经功能恢复有利。

Objective To research the expression and effects of collapsin-response-mediator-protein 2 (CRMP2) in rats spinal cord after brachial plexus injury. Methods The rat model of brachial plexus avulsion was made. The spinal cord was harvested at the 1st, 3rd, 7th, 10th day post-operation. The expression and phosphorylation of CRMP2 were tested using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) and Western blotting. The spatial expression of CRMP2 in spinal cord was tested using immuno-fluorescence method. Further in vitro, CRMP2 was regulated using adenovirus and the effects on axon regeneration were evaluated. Results After 1, 3, 7, 10 days of brachial plexus avulsion, using RT-qPCR and Western blotting, the expression of CRMP2 was significantly increased. On the 3rd and 7th day post-operation, the level of phosphorylation CRMP2 was 0.154±0.113 and 0.124±0.200 in BPI group, while it was 0.342±0.200 and 0.434±0.165 in sham group. The level of phosphorylation CRMP2 was decreased in BPI group. In the spinal cord, CRMP2 was expressed in neurons but not in astrocytes and microglia. In vitro, the length of axon and number of dendrites was 7.066±1.762 and 24.500±8.816 in up-regulated group, while it was 1.044±0.556 and 8.000±3.295 in down-regulated group. Up-regulated CRMP2 resulted in longer axon and more dendrites of neurons. Conclusion After brachial plexus avulsion, increased CRMP2 in spinal cord neurons can promote axon regeneration, which benefits to function recovery.