硫化氢对急性马尾神经损伤模型大鼠的神经保护作用

摘要

背景：研究发现内源性硫化氢可以作为一种新型气体信号分子，具有重要的信号传递功能和生物调节作用。目的：研究硫化氢对急性马尾神经损伤大鼠的神经保护作用。方法：将72只SD大鼠随机均分为3组，实验组、模型组咬除L4椎板，将长10 mm、厚1.0 mm、宽1.0 mm的硅胶条植入大鼠L5和L6椎管内，建立大鼠马尾神经压迫损伤模型；假手术组仅咬除L4椎板，未植入硅胶条；实验组造模前1 h腹腔注射20μmol/kg的NaHS，模型组与假手术组腹腔注射等量生理盐水。造模后12，24，48，72 h检测马尾神经组织中丙二醛和谷胱甘肽水平，同时在48 h取材进行苏木精-伊红染色和TUNEL染色。结果与结论：苏木精-伊红染色显示，假手术组马尾神经纤维致密有序，髓鞘完整，轴突无肿胀；模型组马尾神经纤维松散，脱髓鞘改变，部分轴突及髓鞘肿胀；实验组马尾神经纤维紧密，少量轴突肿胀、脱髓鞘改变。TUNEL染色显示，假手术组中脊髓和背根神经节组织中阳性细胞数量较少，模型组脊髓和背根神经节中可见大量阳性细胞，实验组阳性细胞数量显著低于模型组。假手术组、实验组丙二醛水平低于模型组(P <0.05， P <0.01)，谷胱甘肽水平高于模型组(P <0.05，P <0.01)。表明硫化氢可以降低氧化应激反应，保护急性损伤大鼠马尾神经。%BACKGROUND:Endogenous hydrogen sulfide can be used as a new gaseous signaling molecule, and has important signal transfer function and biological regulation effects. OBJECTIVE:To study the neuroprotective effects of hydrogen sulfide in rats with acute cauda equina syndrome. METHODS: The 72 Sprague-Dawley rats were randomly assigned to three groups. Experimental group, model group: laminectomy was performed at the lumbar 4 (L4) level of the vertebra, and a piece of silicone (10 mm long, 1 mm thick, and 1 mm wide) was placed under the laminae of the L5-6 vertebra to produce the animal model of cauda equina syndrome. Sham surgery group: a simple laminectomy was performed in L4, but silicone was not implanted. In the experimental group, 20 μmol/kg NaHS was injected intraperitonealy at 1 hour before model establishment. Model and sham surgery groups: an equal volume of saline was injected intraperitonealy. At 12, 24, 48 and 72 hours after model establishment, malonaldehyde and glutathione levels in cauda equina nerve tissue were detected. Simultaneously, hematoxylin-eosin staining and TUNEL staining were performed at 48 hours. RESULTS AND CONCLUSION:Hematoxylin-eosin staining demonstrated that cauda equina nerve tissue was dense and regular, with complete myelin sheath, no axon sweling in the sham surgery group. Cauda equina nerve tissue was sparse, with the presence of demyelination, and partial axons and myelin sheath sweling in the model group. Cauda equina nerve tissue was tight, with axonal sweling and demyelination in the experimental group. TUNEL staining demonstrated that the number of positive cels was less in the spinal cord and dorsal root ganglia in the sham surgery group. Abundant positive cels were detected in the spinal cord and dorsal root ganglia in the model group. The number of positive cels was significantly lower in the experimental group than that in the model group. Malonaldehyde levels were lower in the sham surgery and experimental groups than in the model group (P < 0.05, P < 0.01), but glutathione levels were higher than model group (P < 0.05,P < 0.01). These results indicated that hydrogen sulfide could decrease oxidative stress and protect cauda equina nerve in rats with acute cauda equina syndrome.