成年斑马鱼脊髓损伤修复中脑gdnf和nos基因的表达

Expression of gdnf and nos in adult zebrafish brain during the regeneration after spinal cord injury

成年斑马鱼(Danio rerio)具有很强的脊髓损伤后自主修复的能力,但目前其机制不明。为了研究斑马鱼中脑组织对脊髓再生的影响,文章应用成年斑马鱼脊髓损伤模型,采用实时定量PCR方法和原位杂交技术,检测了斑马鱼脑中胶质细胞源性神经营养因子(gdnf)和一氧化氮合酶(nos)基因在脊髓损伤后4 h、12 h、6 d、11 d的表达情况,展示了这两种基因在斑马鱼脑内不同核团的动态表达变化。结果显示,成年斑马鱼脊髓损伤后,神经营养因子gdnf基因在损伤急性期(4 h、12 h)和神经修复期(6 d、11 d)于斑马鱼脑内呈现显著性升高(P<0.05),而一氧化氮合酶基因nos的表达于损伤急性期显著性升高(P<0.05),随后下降,并在修复期(11 d)显著降低(P<0.05)。这表明,脊髓损伤后,高表达gdnf基因同时低表达nos基因的脑环境给脊髓损伤提供了良好的神经再生微环境,从而可能促进轴突的再生长及运动能力的恢复。

Recently,it is unclear about the mechanism of notable regenerated ability of adult zebrafish after spinal cord injury.To investigate the effects of brain on restoration from spinal cord injury,adult zebrafish spinal cord injury model was built and brain samples were dissected at different time points after the injury.Real-time quantitative PCR and in situ hybridization were applied to reveal the dynamics of glial cell line-derived neurotrophic factor（gdnf） and nitric oxide synthases（nos） mRNA expression in various regions of zebrafish brain.The results showed that,compared to sham group at each time points separately,the expression of gdnf mRNA in adult zebrafish brain during both acute phase（4 h and 12 h） and chronic phase of neuroregeneration（6 d and 11 d） increased significantly（P〈0.05）.The expression of nos mRNA in zebrafish brain enhanced during acute phase,and then reduced to the level lower than the sham group during the chronic phase of neuroregeneration（11 d）（P〈0.05）.This suggests that brain may promote neural axons regeneration in spinal cord via a more beneficial microenvironment which retains higher level of gdnf and lower level of nos.