郑家涛，王军，欧绍武，王运杰（中国医科大学附属第一医院神经外科，辽宁　沈阳110001）

成熟型与幼稚型Nav1.5 Na+通道变构体在神经损伤大鼠背根神经节细胞中的表达

郑家涛，王军，欧绍武，王运杰*
（中国医科大学附属第一医院神经外科，辽宁沈阳110001）

目的：研究幼稚型和成熟型Nav1.5 Na+通道变构体在选择性神经损伤（SNI）大鼠背根神经节细胞（DRG）中的表达情况。方法：建立SNI大鼠模型。采用RT-PCR、DNA测序、限制性酶切技术、免疫组化等方法检测幼稚型和成熟型Nav1.5 Na+通道变构体在SNI大鼠DRG中的表达；采用Western blot法检测DRG神经元中蛋白激酶C（PKC）的表达。结果：成熟型和幼稚型Nav1.5 Na+通道变构体在大鼠DRG神经元中的表达比例为2.5∶1。在SNI大鼠模型中，幼稚型和成熟型Nav1.5的mRNA和蛋白表达水平均降低50％左右，PKC-γ表达水平增加大约1倍。结论：幼稚型和成熟型Nav1.5 Na+通道变构体在大鼠DRG中有表达，在疼痛模型中的表达水平显著降低；在SNI模型中，PKC-γ表达水平的上调直接或间接导致了Nav1.5亚型的低表达，此机制可能参与了神经病理性疼痛的发生发展过程。

Nav1.5 Na+通道；背根神经节细胞；疼痛模型

doi：10.16753/j.cnki.1008-2344.2016.04.002

［Abstract］Objective：To study the expression of adult and neonatal Nav1.5 isoforms in the dorsal root ganglia（DRG）neurons of rats with spared nerve injury（SNI）.Methods：The expression of adult and neonatal Nav1.5 isoforms in the DRG neurons of rats with SNI was detected by RT-PCR，DNA sequencing，restriction enzyme digestion，immunohistochemistry and immunofluorescence methods.The expression of PKC-γ was detected by Western blot.Results：Both adult and neonatal Nav1.5 isoforms were expressed in the DRG neurons，but their expression ratio was approximately 2.5∶1.In SNI rat models，the expression of both adult and neonatal Nav1.5 isoforms decreased by approximately a half in both mRNA and protein levels.In contrast，the expression of PKC-γ increased by approximately one-fold.Conclusions：Both adult and neonatal Nav1.5 isoforms expressed in the DRG neurons of rat，but their expression levels decrease in pain models.The up-regulation of PKC-γ may directly or indirectly down-regulate the expression of Nav1.5 isoforms in SNI rat models，which may further involve in the pathological process of neuropathic pain.

［Key words］sodium channel Nav1.5；dorsal root ganglia neurons；pain model

作为跨膜蛋白的电压-门控Na+通道是可兴奋细胞动作电位产生和传导的重要离子通道，在伤害感受性电兴奋中扮演着重要角色［1-2］。电压-门控Na+通道的三维空间结构目前尚不清楚，一般认为它由一个大的α亚单位和2～4个小的β亚单位构成［3］。到目前为止，已有9种Na+通道α亚单位（Nav1.1-Nav1.9）在不同的哺乳动物组织中被克隆出来［4］。除Nav1.4Na+通道变构体外，其余几种Na+通道α亚单位均可在成熟背根神经节（DRG）神经元中检测到表达［5-6］。……