坐骨神经损伤脊髓神经元退变与组织型纤溶酶原激活物及其抑制物表达的关系研究  

Association between neurodegeneration and tissue plasminogen activator and plasminogen activator inhibitors in spinal cord after sciatic nerve transection

作　　者：彭琳[1] 霍霞[2] 徐锡金[2] 

机构地区：[1]汕头大学医学院附属肿瘤医院检验科M汕头515041 [2]汕头大学医学院分析细胞实验室

出　　处：《中华手外科杂志》2012年第1期17-21,共5页Chinese Journal of Hand Surgery

基　　金：广东省教育厅自然科学研究项目（Z03037）

摘　　要：目的 探讨坐骨神经离断后脊髓内组织型纤溶酶原激活物（tissue plasminogen activator,tPA）及其抑制物纤溶酶原激活物抑制物1（type-1 plasminogen activator inhibitor,PAI-1）、神经丝氨酸蛋白酶抑制剂（neuroserpin,NSP）的表达与神经元退变的关系.方法 将56只雄性SD大鼠随机分为实验组和对照组.对实验组大鼠行坐骨神经离断术,于术后各时间点取材伤侧脊髓L4～6节段,经Nissl染色后,运用透射电镜观察神经元退变及死亡情况；运用免疫组化染色和半定量RT-PCR检测tPA、PAI-1及NSP的表达变化.结果 坐骨神经离断术后7d,伤侧相应脊髓节段前角外侧核神经元存活率显著下降,术后21 d神经元存活率为61.6％.电镜观察显示,术后7d开始,脊髓前角可见处于不同凋亡阶段的神经元及神经胶质细胞,术后14 d开始脊髓后角也可见少数凋亡样变的神经元及胶质细胞.免疫组化结果显示,坐骨神经损伤后ld,伤侧脊髓Ⅴ～Ⅸ板层内tPA表达水平开始上调（P＜0.05）,第7天时达到高峰后下降,至术后21 d仍未恢复正常水平（P＞0.05）；PAI-1则在正常脊髓及损伤后脊髓均未能检测到.半定量RT-PCR结果显示,tPA的mRNA变化趋势与蛋白表达基本相同,略早于后者；NSP的mRNA术后1d内迅速上调,随后2周都处于较高水平,21 d才基本回复正常.结论 坐骨神经离断后同侧相应脊髓节段近50％的前角运动神经元死亡可能与损伤刺激脊髓灰质内神经元和小胶质细胞合成、释放tPA增加有关,同时损伤也促使tPA抑制物NSP表达上调,后者可能发挥神经保护作用.Objective To investigate whether tissue plasminogen activator（tPA）,type Ⅰ plasminogen activator inhibitor（PAI-1）and neuroserpin（NSP）are involved in neurodegeneration following sciatic nerve transection in rats.Methods Fifty-six male Sprague Dawley rats were randomly divided into normal group and sciatic nerve transection group.Spinal cord from level L4 to L6 was removed at several time points after sciatic nerve transection for Nissl staining and transmission electron microscopy to evaluate neurodegenerative changes and neuronal death.The dynamic expression of tPA,NSP and PAI-1 were examined by immunohistochemical staining and semi-quantitative reverse transcription-polymerase chain reaction（RT-PCR）.Results Statistically significant neuron loss in spinal anterior horn of the injured side was found 7 days following sciatic nerve transection.The neuron survival rate at 21 days after the operation was 61.6%.Furthermore transmission electron microscopy showed a considerable number of apoptotic neurons and glia cells at various phases in the anterior horn from 7 days postoperatively.Furthermore,a few apoptotic cells could be detected in the posterior horn at 14 days after the operation as well.The results of immunohistochemistry showed that tPA was up-regulated in laminae Ⅴ to Ⅸ of the injury side by 1 day post-lesion（P 〈 0.05）and peaked at 7 days.After that,tPA protein was down-regulated.But until the time point of 21 days,the level of tPA had not returned to the normal level（P 〉 0.05）.However,PAI-1 could be detected in neither normal nor experimental spinal cord.Semi RT-PCR revealed a change tendency of tPA mRNA that was similar to tPA protein but just a little earlier than the latter.Meanwhile,NSP mRNA was up-regulated by 1 day and stayed at a higher level for two weeks.It returned to normal level at 21 days.Conclusion The 50% motor neuron loss in the ipsilateral spinal cord anterior horn after sciatic nerve transection was related to the upregulation of synthesis and release of tP

关 键 词：坐骨神经 脊髓 神经元 退变 组织型纤溶酶原激活物 

分 类 号：R651.3[医药卫生—外科学]