Kobayashi Shigeru, Uchida Kenzo, Kokubo Yasuo, Takeno Kenichi, Yayama Takafumi, Miyazaki Tsuyoshi, Nakajima Hideaki, Nomura Eiki, Mwaka Erisa, Baba Hisatoshi
Department of Orthopedic Surgery and Rehabilitation Medicine, Fukui University School of Medicine, Shimoaizuki, Matsuoka, Yoshida, Fukui, Japan.
Spine (Phila Pa 1976). 2008 Apr 1;33(7):716-23. doi: 10.1097/BRS.0b013e318169500e.
This study was aimed at investigating changes in the dorsal horn of the lumbar cord induced by mechanical compression using an in vivo model.
To determine the effect of axonal flow disturbance in the dorsal horns induced by nerve root compression.
Few studies have looked at changes of synapses within the dorsal horn caused by disturbance of axonal flow and the axon reaction as a result of mechanical compression of the dorsal root.
In mongrel dogs, the 7th lumbar nerve root was compressed for 1 week, or 3 weeks using a clip. After intravenous injection of Evans blue albumin, they were observed under a fluorescence microscope for the purpose of clarifying the function of the blood-spinal cord barrier. Morphologic changes of the synapses in the dorsal horns secondary to the nerve fiber degeneration were examined by light and electron microscope. Changes on immuno-staining for substance P, calcitonin gene-related peptide, and somatostatin in the dorsal horn were also examined.
Light microscope observation conducted 1 week after compression of the nerve roots revealed Wallerian degeneration of the myelinated nerve in the dorsal horn, and fluorescence microscope observation of these areas demonstrated edema formation resulting from damage of the blood-spinal cord barrier. Three weeks after the compression, electron microscope observation revealed shrinkage of the axon terminals, ubiquitous presence of high electron density degeneration and presence of synapses whose contact with synapses was disrupted. Immuno-histochemical studies showed a marked decrease of substance P, calcitonin gene-related peptide, and somatostatin staining in substance gelatinosa with Wallerian degeneration after compression of nerve root.
It is important to recognize that compressive disturbance of the nerve roots caused Wallerian degeneration not only at the site of compression of nerve roots but also at the synapses of spinal cord dorsal horns.
本研究旨在利用体内模型研究机械压迫诱导的腰髓背角变化。
确定神经根压迫诱导的背角轴突运输紊乱的影响。
很少有研究关注轴突运输紊乱和背根机械压迫导致的轴突反应引起的背角内突触变化。
在杂种犬中，使用夹子对第7腰神经根进行1周或3周的压迫。静脉注射伊文思蓝白蛋白后，在荧光显微镜下观察以阐明血脊髓屏障的功能。通过光学显微镜和电子显微镜检查继发于神经纤维变性的背角突触的形态学变化。还检查了背角中P物质、降钙素基因相关肽和生长抑素免疫染色的变化。
神经根压迫1周后进行的光学显微镜观察显示背角有髓神经发生华勒变性，对这些区域的荧光显微镜观察显示血脊髓屏障受损导致水肿形成。压迫3周后，电子显微镜观察显示轴突终末萎缩，普遍存在高电子密度变性，以及突触与突触接触中断的情况。免疫组织化学研究显示，神经根压迫后，胶状质中P物质、降钙素基因相关肽和生长抑素染色随华勒变性显著减少。
必须认识到神经根的压迫性紊乱不仅在神经根受压部位，而且在脊髓背角突触处都引起了华勒变性。
