目的:观察和探讨Spmgue Dawley(SD)大鼠马尾急性压迫后腰骶部脊髓p75神经营养因子受体(p75NTR)的mRNA表达和腰骶髓神经元细胞凋亡数量时间分布及关系,为马尾综合征(caudaequina syndrome,CES)发病机制提供一定理论依据.方法:成年雌性SD大鼠60只,按时间点随机分为正常对照组及压迫1、3、5、7、14、28 d组,共计12组(n=5),造模采用L3,4节段椎管放置硅胶棒压迫70%～80%椎管面积造成马尾急性压迫症状,于术后1、3、5、7、14、28 d处置,在L1,2椎体位置脊髓取材.分别采用Tunel方法检测神经元细胞凋亡,RT-PCR方法观察p75NTR的mRNA表达.结果:压迫组从术后1～28 d,p75 mRNA表达增加及腰骶髓神经元细胞凋亡明显,p75 mRNA表达和凋亡数目变化趋势存在先升高后降低同步趋势,均在7 d达到峰值,压迫组术后各时间点与对照组比较差异有统计学意义(P＜0.05),压迫组与对照组总体差异有统计学意义(P＜0.05),p75NTR的mRNA表达与腰骶部神经元细胞的凋亡呈正相关.结论:马尾急性压迫后,p75NTR的mRNA与神经元细胞凋亡密切相关,在CES的分子发病机制中发挥重要作用.%Objective :To observe the mRNA expression of p75NTR (p75 neurotrophin receptor)and the amount of neuronal cells apoptosis in lumbar-sacral spinal cord at different time points after the acute cauda equina compression in rats and to explore their correlation.Methods: Sixty adult female Sprague Dawley (SD) rats were randomly divided into the normal control group and the compression groups.The acute cauda equine compression model was established as placing a silicon gel rubber at L3,4 level of the vertebral canal which represented about 70％ to 80％ compression to the cross section.The whole L1,2 level of spinal cords were harvested at 1,3,5,7,14,28 d after operation in compression group.Tunel method was applied to observe cell apoptosis and RT-PCR was used to detect the p75NTR mRNA expression.SPSS 13.0 statistical software was adopted to help analysis.Results:In the compression group, both the nerve cells apoptosis and the p75 mRNA expression existed the trend of low-high-low synchronally compared with the control group,there was a significant difference (P＜0.05) among comprssion groups at different time points, there was a significant difference in changes (P＜0.05).p75NTR of mRNA expression and lumbosacral nerve cells apoptosis was in a positive correlation.Conclusion:After acute cauda equina compression, p75NTR mRNA expression is closely related to the neuronal apoptosis,which plays an important role in the molecular mechanism of the CES.
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