Nogo-A在脊髓损伤大鼠脊髓组织中的动态表达

关键词：脊髓损伤  Nogo-A  神经再生  大鼠  神经生长抑制因子

Keywords:spinal cord injury  Nogo-A  nerve regeneration  rats  nerve growth inhibiting factor

摘要：

      摘要 目的：观察大鼠脊髓损伤后神经生长抑制因子Nogo-A在脊髓组织中的动态表达变化，探讨Nogo-A蛋白在神经再生过程中的意义和作用。 方法：选用108只SD大鼠随机分成正常组、假手术组和模型组，每组36只，A组不做任何处理，B组咬除T9-T11棘突及椎板，避免损伤脊髓；C组按照改良Allen法造模。分别于干预后24h、第3天、第7天、第14天处死大鼠，每组9只，以免疫组化及Western Blot检测各组大鼠脊髓组织中Nogo-A蛋白的表达变化，以荧光定量PCR检测Nogo-A mRNA表达变化。 结果：正常组、假手术组各时间点Nogo-A蛋白和mRNA无显著变化（P＞0.05）。模型组在损伤后24h Nogo-A 蛋白和mRNA表达较低，3d后下降至最低，7d后迅速上升达到高峰，至14d逐渐下降，但仍高于假手术组；与假手术组比较，模型组在损伤后7d、14d，Nogo-A蛋白和mRNA表达均明显增高，差异均有显著性意义（P＜0.05）。 结论：大鼠脊髓损伤后，Nogo-A蛋白在早期一过性下降后可持续保持高水平表达，可能是造成脊髓损伤后中枢神经系统神经再生困难的重要原因之一。

Abstract:

      Abstract Objective:To observe the dynamic expression of nerve growth inhibiting factor——Nogo-A in spinal cord of rats after spinal cord injury（SCI）, and to explore the meaning and function of Nogo-A protein in the course of nerve regeneration. Method:A total of 108 SD rats were randomly assigned into normal group(A), sham operated group(B) and model group(C), each group 36 rats. The rats in group A were not operated on, group B were bited except T9—T11 spinous process and lamina, avoiding injury of spinal cord, group C was made according to the modified Allen's method. The rats were all sacrificed on the 24th h, 3rd d, 7th d and 14th d after intervention respectively, each group 9 rats. Nogo-A protein expression changes of spinal cord in rats were detected by immunohistochemistry and Western blot, Nogo-A mRNA expression changes were detected by fluorescence quantitative PCR. Result:The expressions of Nogo-A protein and mRNA had no significant change in normal group and sham operated group (P>0.05). In model group protein and mRNA expressions reduced after 24h of SCI,and dropped to the lowest level after 3d, then rapidly rised to peak after 7d, and gradually declined after 14d, but the expressions of Nogo-A protein and mRNA were still higher than that in sham operated group. Compared with sham operated group, the expressions of Nogo-A protein and mRNA increased significantly on 7d and 14d after injury, and the differences had statistical significance (P<0.05). Conclusion:Nogo-A protein expression kept on the hign level after transient drop at early stage in spinal cord of rats, which maybe one of the important condition about the difficulty of nerve regeneration in central nervous system after SCI.