腺病毒介导的脑源性神经营养因子基因脊髓内转移对神经根损伤后细胞凋亡的影响

目的观察腺病毒介导的脑源性神经营养因子（BDNF）基因脊髓内转移对神经根损伤后细胞凋亡的影响。方法在大鼠神经根切断吻合模型基础上，通过显微注射法在立体定位仪上将复制缺陷型重组腺病毒载体（AxCA-BDNF）直接转移至大鼠神经根损伤部相应的脊髓腹角。术后1、3、7、14、28d利用DNA末端原位标记、免疫组化、原位杂交，观察脊髓凋亡细胞、Caspase-3、bcl-2及iNOS表达的改变。结果神经根损伤诱导Caspase-3和iNOS的表达，触发运动神经元凋亡；AxCA-BDNF治疗后腹角运动神经元不但较少表达Caspase-3和iNOS，而且bcl-2表达增加，发生凋亡的细胞减少。结论AxCA-BDNF介导的外源性BDNF基因转染对脊髓运动神经元具有保护作用，其作用机制与AxCA—BDNF抑制内源性的死亡程序有关。

Effects of gene transfer of adenovirus-mediated brain-derived neurotrophic factor into spinal cord on apoptosis after nerve root injury

Objective To investigate the effects of recombinant adenovirus-mediated brain-derived neurotrophic factor （BDNF） gene transfer into spinal cord on apoptosis after nerve root injury. Methods Nerve root transection and reanastomosis were used as the experimental model. The vector of recombinant adenovirus-mediated BDNF was transferred into spinal ventral horn through microinjection in a stereotaxic frame. TUNEL reaction, immunohistochemistry and situ hybridization were used to investigate cellular apoptosis and the expression of caspase-3, bcl-2 and iNOS on 1, 3, 7, 14, 28 days after injury. Results Nerve root injury induced the expression of caspase-3 and iNOS, which triggered the procedure of apoptosis. It showed that AxCA-BDNF gene transfer not only inhibited caspase-3 and iNOS expression, but also increased bcl-2 expression, companying with the decreased apoptotic cells. Conclusion AxCA-BDNF gene transfer protects neurons from delayed death by the mechanisms of blocking neuronal apoptosis.