脊髓损伤后促红细胞生成素对bcl-2的影响

目的 探讨促红细胞生成素（EPO）对大鼠脊髓损伤后伤区脊髓细胞凋亡和神经功能恢复的影响。方法 Wistar大鼠210只，随机分为4组：假手术组、脊髓损伤组、脊髓损伤加重组人EPO治疗组、脊髓损伤加生理盐水治疗组。采用原位末端脱氧核糖核苷酸转移酶介导dUTP标记（TUNEL标记法）检测神经元和少突胶质细胞凋亡，Western blot免疫印迹法和免疫组化染色检测bcl-2表达，免疫组化染色和图像分析方法观察对白质内神经纤维（NF-200染色）的保护作用，通过感觉诱发电位（SSEP）、运动诱发电位（MEP）和大鼠BBB后肢运动功能评分，观察损伤脊髓传导功能的恢复。结果 EPO保护组bcl-2在各时相点的表达明显增高，8h和7d时神经元和少突胶质细胞的TUNEL阳性细胞数明显减少；在7d时白质中NF-200阳性神经纤维明显增多；SSEP和MEP的平均潜伏期和波幅以及BBB功能评分明显提高，与损伤组和生理盐水治疗相比，差异有统计学意义（P〈0．01）。结论 EPO通过上调bcl-2的表达，在抑制脊髓损伤后神经元和少突胶质细胞的凋亡中起到神经保护作用。

Effect of erythropoietin on expression and its significance of bcl-2 in the rats after spinal cord injury

Objective To investigate the effect of erythropoietin(EPO) on neural apoptosis and neurological functional recovery after traumatic spinal cord injury in the rat. Methods Rats were randomly divided to four groups: control group, spinal cord injury group, spinal cord injury group administration with recombinant human EPO, spinal cord injury group administration with normal saline. The neuronal and glial cell apoptosis of spinal slice from the injured spinal cord was examined by the terminal deoxynucleotidal transferase-mediated dUTP-biotin nick end labeling (TUNEL) reaction. The expression of bcl-2 at different time point were detected by Western blot and immunohistochemical staining. The axons were stained immunohistochemically with anti-NF. Analyse the results by the system of image processing. The locomotor behavior of all rats was analyzed by the BBB open field test and somatosensory (SSEP) and motor evoked potentials (MEP). Results Tunel-positive neuronal and glial cell were significantly decreased at 8h and 7d, the bcl-2 protein level was maximal 6 and 12h after the injury and still significantly higher at 7d post-injury. NF-positive axons were significantly increased, the average latency and amplitude of SSEP and MEP were improved significantly and the mean of BBB scores showed significant improvement in EPO-treated groups. Statistical analysis showed that a significant difference from the injured groups (P<0.01). Conclusion Exogenous EPO can obviously induced the expression of bcl-2 which inhibited the neuronal and glial cell apoptosis in the rats after spinal cord injury, which may play a significant neuroprotection in secondary events in spinal cord injury.