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导致神经组织损伤，包括损伤水平周围前角细胞的丢失。神经营养因子外源性输送到神经元细胞中，可对机械损伤后的脊髓提供神经保护。我们研究了携带神经营养因子(NT)-3基因的腺病毒载体（AdV）靶向转染C1-C2水平慢性和进行性机械压迫的twy （twy/twy）小鼠脊髓前角神经元的神经保护作用。将AdV-NT-3和adv -p-半乳糖苷酶cDNA （LacZ）作为标记基因，经胸锁乳突肌逆行递送至16周龄脊髓受压成年小鼠颈脊髓副运动神经元。注射AdV-NT-3或AdV-LacZ后4周，对压缩后的颈脊髓进行组织学、免疫组织学检查和免疫印迹分析。与注射AdV-LacZ的小鼠相比，转染adv -NT-3的小鼠对NT-3的免疫反应性显著增强。转染adv - nt -3的小鼠脊髓前角神经元中Nissl-、胆碱乙酰转移酶染色的神经元和小麦胚芽凝集素-辣根过氧化物酶标记的神经元数量显著高于转染adv - lacz的小鼠。逆行转染AdV-NT-3轴突可增加小鼠前角神经元的轴突长度和wga - hrp标记神经元的树突化。我们的研究结果表明，靶向逆行NT-3基因递送在完整动物中是可行的，即使在脊髓慢性机械压迫下，它也能提高神经元的存活率。

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.