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

摘要

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。%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 immunofluo-rescence methods. The expression of PKC-γwas 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-γincreased 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-γmay 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.