【摘要】 目的观察大鼠马尾神经受压后脊髓圆锥神经元的形态变化,检测脊髓神经元凋亡数量及脑源性神经营养因子(BDNF)mRNA的表达,以及探讨上述变化的可能机制。方法将90只成年SD大鼠分为马尾受压模型组、假手术组与正常对照组,分别于造模术后30min、2h、4h、8h、1d、3d、1周、2周、3周取样。采用光镜与透射电镜观察马尾受压后脊髓圆锥神经细胞的形态变化;采用原位缺口末端标记(TUNEL)技术检测细胞凋亡;原位杂交法测定BDNF mRNA阳性细胞的数量。计算单位面积内的阳性细胞数,单因素方差分析比较马尾受压后不同时间组与对照组之间的差异。结果马尾神经受压可导致脊髓圆锥神经元形态结构出现明显伤害性改变。TUNEL染色与BDNF mRNA原位杂交显示,阳性细胞分别于制模术后8h、4h起较对照组有明显增多,并于术后3d达高峰,术后3周上述阳性细胞的数量仍明显高于对照组。结论马尾神经受压后,可导致相应脊髓圆锥神经细胞结构的明显变化,其凋亡数量明显增加,说明马尾受损可导致中枢神经元的不可逆损伤,这可能是马尾综合征逾期手术效果不理想的重要原因之一。在马尾严重受压后,神经元及胶质细胞的BDNFmRNA的表达明显增加,可能对神经细胞的保护及修复起一定作用。更多还原

【Abstract】 Objective To investigate the morphological changes,apoptosis and brain-derived neurotrophic factor mRNA(BDNF mRNA)expression in rat conus medullaris induced by cauda equine compression,and to discuss the possible mechanisms. Methods Ninety male SD rats were divided into 3 groups: normal control,sham operation,and cauda equine compressed.The animals were sacrificed and took samples in 30 min,2 hours,4 hours,8 hours,1 day,3 days,1 week,2 weeks,3 weeks after cauda equine compression model were created.The morphological study concerned with cauda equina and conus medullaris was done under light microscope and transmission electron microscope.TUNEL staining and in situ hybridization staining were used to investigate apoptosis and BDNF mRNA expression changes.The positive cells in 1mm~2 were calculated,and the data were disposed through one way analysis of variance. Results Histological observation showed notable alteration of cauda equina and neurons in conus medullaris.The positive cells of TUNEL and BDNF mRNA in situ hybridization staining increased in 8 hours and 4 hours after cauda equina compressed,and both reached the climax in 3days after cauda equina compressed.At the time 3weeks after cauda equine compressed,the positive cells were still much higher than that of the control groups.Conclusion The compression of cauda equina will result in neurons morphological changes and apoptosis in medullary cone,and cause central neuron un-reversible injury.It might be one of the reasons why the prognosis is poor in cauda equina syndrome.Neurons and glial cells may produce BDNF by themselves to survival from cauda equina compression.更多还原