Chou An Kuo, Yang Lin Cheng, Wu Ping Ching, Wong Wen Tsang, Liu Guei Sheung, Chen Jing Tsang, Howng Shen-Long, Tai Ming-Hong
Department of Anesthesiology, Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
Brain Res Mol Brain Res. 2005 Feb 18;133(2):198-207. doi: 10.1016/j.molbrainres.2004.10.036.
Paraplegia is a catastrophic complication of thoracic aortic surgery. At present, there is no effective mean to prevent the ischemia-induced spinal cord trauma. Gene delivery of neurotrophic factors may hold promises for prevention of spinal injury. In the present study, we evaluated the effect of glial cell line-derived neurotrophic factor (GDNF) gene delivery on prevention of the pathological changes due to spinal ischemia. Recombinant adenovirus vectors encoding GDNF (Ad-GDNF) and green fluorescent protein (Ad-GFP) were used for gene transfer studies. Treatment with cobalt chloride induced dose-dependent bcl-2 and synaptophysin downregulation in spinal neuronal cells, which could be effectively reversed by GDNF gene transfer. Intrathecal injection of Ad-GDNF led to maximal GDNF expression in spinal cord within 2-7 days. Thus, after intrathecal administration of adenovirus vectors for 3 days, Sprague-Dawley rats received transient aortic occlusion to induce spinal ischemia and were monitored for behavior deficits. The Ad-GDNF-treated rats showed significantly lower paraplegia rate (40%) than that of Ad-GFP- or saline-treated groups (75-85%; P<0.01). In addition, the Ad-GDNF-treated rats exhibited significantly improved locomotor function comparing with rats of control groups (P<0.001). Histological analysis revealed that GDNF gene delivery profoundly attenuated the infiltration of leukocytes in spinal cord after ischemic insults. Furthermore, GDNF gene delivery prominently attenuated the ischemia-induced neuronal loss in dorsal horn lamina VI-VIII and reduction in synaptophysin expression in spinal cords. In conclusion, GDNF gene transfer confers protection to the neuronal cells and synapses networks, thereby alleviated the paraplegia due to spinal ischemia.
截瘫是胸主动脉手术的灾难性并发症。目前，尚无有效的方法来预防缺血性脊髓损伤。神经营养因子的基因递送可能为预防脊髓损伤带来希望。在本研究中，我们评估了胶质细胞源性神经营养因子（GDNF）基因递送对预防脊髓缺血所致病理变化的作用。使用编码GDNF（Ad-GDNF）和绿色荧光蛋白（Ad-GFP）的重组腺病毒载体进行基因转移研究。氯化钴处理可诱导脊髓神经元细胞中bcl-2和突触素表达呈剂量依赖性下调，而GDNF基因转移可有效逆转这种下调。鞘内注射Ad-GDNF可在2 - 7天内使脊髓中GDNF表达达到最大值。因此，在鞘内注射腺病毒载体3天后，对Sprague-Dawley大鼠进行短暂性主动脉阻断以诱导脊髓缺血，并监测其行为缺陷。接受Ad-GDNF治疗的大鼠截瘫发生率（40%）显著低于接受Ad-GFP或生理盐水治疗的组（75 - 85%；P<0.01）。此外，与对照组大鼠相比，接受Ad-GDNF治疗的大鼠运动功能有显著改善（P<0.001）。组织学分析显示，GDNF基因递送可显著减轻缺血损伤后脊髓中白细胞的浸润。此外，GDNF基因递送可显著减轻缺血诱导的脊髓背角VI - VIII层神经元丢失以及脊髓中突触素表达的减少。总之，GDNF基因转移可为神经元细胞和突触网络提供保护，从而减轻脊髓缺血所致的截瘫。
