背景：Nogo-A蛋白是表达于少突胶质细胞的神经元轴突生长抑制因子，推测其可能与一氧化碳中毒后迟发性脑病关系密切。单唾液酸四己糖神经节苷脂可改善一氧化碳中毒所致的神经系统损害，其作用是否与少突胶质细胞上Nogo-A蛋白有关目前尚无报道。目的：从少突胶质细胞Nogo-A的角度探讨神经节苷脂对神经细胞一氧化碳损伤后保护的机制。方法：体外培养大鼠视神经少突胶质细胞。实验分为3组：对照组、一氧化碳组、单唾液酸四己糖神经节苷脂组。后两组在含有体积分数1%一氧化碳的密室中培养，单唾液酸四己糖神经节苷脂组预先在培养液中加入5 mg/L单唾液酸四己糖神经节苷脂。采用RT-PCR及细胞免疫组织化学观察6，24，48 h少突胶质细胞Nogo-A mRNA及其蛋白质的表达。结果与结论：一氧化碳组6，24及48 h各间点Nogo-A mRNA积分吸光度比值、Nogo-A蛋白质表达的累计吸光度值均显著高于对照组(P <0.05)；一氧化碳处理后24 h，单唾液酸四己糖神经节苷脂组Nogo-A mRNA积分吸光度比值、蛋白质表达的累计吸光度值均显著高于对照组(P <0.05)，但低于一氧化碳组(P <0.05)；Nogo-A mRNA水平与蛋白质表达具有线性相关性(r=0.95)。提示一氧化碳本身可使少突胶质细胞进入活跃的功能状态，提高Nogo-A的转录和翻译水平；Nogo-A蛋白质表达的增加为其mRNA水平水平提高所致；单唾液酸四己糖神经节苷脂对神经细胞急性一氧化碳损伤的保护作用与抑制少突胶质细胞Nogo-A表达有关。%BACKGROUND:Nogo-A protein is speculated to have close relationship to delayed encephalopathy after carbon monoxide poisoning because it is a kind of neurite growth inhibitor expressing in oligodendrocytes. Monosialotetrahexosylganglioside can improve nerve damage after carbon monoxide poisoning, but no reports is concerned about whether the neuroprotective efect of ganglioside is related to Nogo-A protein. OBJECTIVE:To investigate the protective mechanism of ganglioside on nerve cels after carbon monoxide poisoning from the perspective of Nogo-A in oligodendrocytes. METHODS:Rat oligodendrocytes cultured in vitro were divided into three groups: control, carbon monoxide and monosialotetrahexosylganglioside groups. Carbon monoxide and monosialotetrahexosylganglioside groups were cultured in an airtight box containing 1% carbon monoxide. 5 mg/L monosialotetrahexosylganglioside was added into the culture medium of monosialotetrahexosylganglioside group in advance. The expression of Nogo-A mRNA and protein at 6, 24, 48 hours were detected by RT-PCR and immunohistochemistry method, respectively. n RESULTS AND CONCLUSION:The integrated absorbance values of Nogo-A mRNA and cumulative absorbance values of Nogo-A protein in the carbon monoxide group at 6, 24 and 48 hours were significantly higher than those in the control group (P < 0.05). At 24 hours after carbon monoxide treatment, the integrated absorbance value and cumulative absorbance value of Nogo-A were both higher than those in the control group (P < 0.05), but lower than those in the carbon monoxide group (P < 0.05). The integrated absorbance values of Nogo-A mRNA was significantly associated with the cumulative absorbance values of Nogo-A protein (r=0.95).These findings indicate that carbon monoxide can activate oligodendrocytes, and raise the transcription and translation levels of Nogo-A. The increase expression of Nogo-A protein was due to the high level of Nogo-A mRNA. The protective mechanism of ganglioside on nerve cels after carbon monoxide poisoning is related to inhibition of Nogo-A expression in oligodendrocytes.
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