Retrograde transfection of adenovirus vector carrying neurotrophin-3 gene enhances survival of anterior horn neurons of twy/twy mice with chronic mechanical compression of the spinal cord

脊髓的慢性机械压迫会导致神经组织损伤，包括损伤水平周围的前角细胞丢失。外源性神经营养因子对脊髓损伤后的神经细胞具有保护作用。目的：研究携带神经营养素（NT）-3基因的腺病毒载体（AdV）对慢性和进行性机械压迫的小鼠脊髓前角神经元的保护作用。将腺病毒NT-3和LacZ作为标记基因，经胸锁乳突肌逆行注射到16周龄脊髓压迫的成年twy小鼠颈段脊髓副运动神经元。注射AdV-NT-3或AdV-LacZ 4周后，对压迫的颈脊髓进行组织学、免疫组织学和免疫印迹分析。与AdV-LacZ注射小鼠相比，AdV-NT-3转染的twy小鼠对NT-3的免疫反应性显著增强。在最大压迫的脊髓水平，尼氏染色、胆碱乙酰转移酶染色和麦胚凝集素-辣根过氧化物酶标记的神经元的前角神经元数量在AdV-NT-3转染的小鼠中显着高于AdV-LacZ转染的twy小鼠。逆行转染腺病毒NT-3可增加小鼠前角神经元轴突长度和WGA-HRP标记神经元的树枝状化。我们的研究结果表明，有针对性的逆行NT-3基因传递是可行的，在完整的动物，它提高了神经元的生存，即使在慢性机械压迫脊髓。

Chronic mechanical compression of the spinal cord causes neural tissue damage, including loss of anterior horn cells around the level of injury. Exogenous delivery of neurotrophins to neuronal cells could provide neuroprotection to spinal cord subjected to mechanical injury. We investigated the neuroprotective effects of targeted transfection of adenovirus vector (AdV) carrying neurotrophin (NT)-3 gene into twy (twy/twy) mouse spinal cord anterior horn neurons with chronic and progressive mechanical compression at C1-C2 level. AdV-NT-3 and AdV-p-galactosidase cDNA (LacZ) as a marker gene, were used for retrograde delivery via the sternomastoid muscle to the cervical spinal accessory motoneurons in 16-week-old adult twy mice with spinal cord compression. Four weeks after the AdV-NT-3 or AdV-LacZ injection, the compressed cervical spinal cord was examined histologically, immunohistologically and by immunoblot analysis. Immunoreactivity to NT-3 was significantly enhanced in AdV-NT-3-transfected twy mice than in AdV-LacZ injected mice. The numbers of anterior horn neurons of Nissl-, choline acetyltransferase-stained and wheat germ agglutinin-horseradish peroxidase-labeled neurons at the spinal cord level with maximum compression were significantly higher in AdV-NT-3-transfected than in AdV-LacZ-transfected twy mice. Retrograde AdV-NT-3 axonal transfection in twy mouse anterior horn neurons increased neurite axonal length and of arborization of WGA-HRP-labeled neurons. Our results suggest that targeted retrograde NT-3 gene delivery is feasible in the intact animal and that it enhances neuronal survival even under chronic mechanical compression of the spinal cord.