脊髓全横断损伤后凋亡因子Fas和FasL的表达变化

本研究通过制备SD大鼠脊髓全横断性损伤模型,应用免疫组织化学ABC法和灰度值测定揭示促凋亡因子Fas和FasL在脊髓完全性损伤后,不同时间点之间的相互变化趋势,以探讨Fas和FasL在脊髓损伤中的作用。结果显示:正常和脊髓全横断损伤后的不同时间组SD大鼠脊髓灰质的前角神经元中均可观察到Fas和FasL的免疫阳性产物。与正常组比较,Fas、FasL阳性神经元细胞数在术后1、3、7、14d组均升高(P<0.05),21d组则降低(P<0.05)。前角Fas、FasL阳性神经元的灰度值在术后1、3、7d组较正常组降低(P<0.05),14、21d组无显著性差异(P>0.05)。结果提示大鼠脊髓全横断损伤后,在损伤节段尾侧脊髓前角神经元Fas与FasL的表达经历了由增高到降低的过程,Fas和FasL表达增加有诱导神经细胞凋亡的趋势,可能参与诱导了脊髓继发性损伤。

THE EXPRESSION OF Fas AND FasL FACTORS FOLLOWING SPINAL CORD COMPLETE TRANSECTION INJURY

To investigate the effect of Fas and FasL in spinal injury we examined the expression tendency of Fas and FasL, which can promote the apoptosis at different period of spinal injury, with immunohistochemical ABC staining and quantitative grey density analysis on SD rats received complete spinal cord transection. Fas and FasL immunoreactivities were observed in motorneurons of spinal cord anterior horn in both control and injured groups. Compared with the control group, the number of Fas and FasL positive neurons in injured group increased at postoperation day 1,3,7,14 (P<0.05), but it began to decrease at 21 d after operation(P<0.05). The averaged grey value of Fas and FasL positive neurons in the control group was higher than that in 1, 3 or 7 d group (P<0.05), but no apparent changes were observed when compared with that in the 14 or 21 d group (P>0.05). These results indicate that after complete spinal transection injury, the expression level of Fas and FasL in motoneurons in the caudal part of the traumatic spinal segment of SD rat undergoes the process of increase to decrease. The expressing increase of Fas and FasL may, therefore, induces neuronal apoptosis and makes an effect on the spinal secondary injury.