目的：研究急性一氧化碳（ carbon monoxide ， CO ）中毒致迟发性脑病（ delayed neuropsychologic sequelae ， DNS ）大鼠胼胝体的损伤及神经生长抑制因子 A （ neurite outgrowth inhibitor-A， Nogo-A）的表达情况。方法腹腔内分次注射CO气体造成DNS模型，于不同时间点取胼胝体。HE染色观察细胞形态，变色酸染色观察脱髓鞘改变，免疫组化检测观察Nogo-A蛋白表达，荧光定量聚合酶链式反应（ real time polymerase chain reaction ， RT-PCR）检测Nogo-A mRNA表达，电镜观察胼胝体超微结构变化。结果中毒组光镜下胼胝体出现脱髓鞘等变化，以造模成功后0 h变化较明显。免疫组化显示，Nogo-A在各时间点均高表达（P＜0．05）。 RT-PCR于造模成功后0、12、24 h高表达（P＜0．05），0 h为高峰，其后逐渐下降，第3天与对照组比较差异无统计学意义，中毒组第7天表达再次升高（P＜0．05）。电镜下，胼胝体出现相应改变。结论 CO中毒后大鼠胼胝体出现脱髓鞘损伤，且与Nogo-A表达相关。%Objective To investigate the change in neurite outgrowth inhibitor -A ( Nogo-A) and injury of the corpus callosum of rats with delayed neuropsychologic sequelae ( DNS ) after acute carbon monoxide (CO) poisoning.Methods Healthy Male SD rats were divided into control group and poisonous group randomly .Poisonous group was given intraperitoneal injections of CO to make models of DNS.Corpus callosum was taken from the poisonous rats at 0 h, 12 h, 24 h, 3 d and 7 d after successful modeling , and the sample for control group was paralleled taken at the same time points .HE staining was performed to observe the changes of cellular morphology .Chromotropic acid staining was used to observe myelin changes .Immunohistochemical method was used to observe the expression of Nogo-A.The mRNA levels of Nogo-A at 0 h, 12 h, 24 h, 3 d and 7 d of poisonous group and control group were detected by real -time quantitative polymerase chain reaction ( RT -PCR ) . The ultrastructure was observe under the electron microscope .Data was analyzed with SPSS17.0.Results The rats in poisonous group appeared leukoaraiosis and neuron pyknosis by HE staining , and white matter demyelination by chromotropic acid staining .The most significant damage was shown in 0 h group of successful modeling and over time we found a mitigation of the injury by two staining methods . Immunohistochemical results showed that Nogo -A expressed all the time in poisonous group while its expression on day 3 began to decline .RT -PCR results showed that Nogo -A mRNA expressed in normal corpus callosum .The mRNA level of Nogo -A increased at the 0 h and lasted to 24 h.Its expression reached a peak at 0 h.The expression of Nogo -A mRNA began to decrease on day 3, which declined near the control group .On day 7, the level of Nogo -A mRNA rose again.Myelin shelf structure loose solution , fusion and fracture were observed in the corpus callosum while the density of axone was thin of poisonous group under the electron microscope .Conclusion Demyelination injury characterized by corpus callosum appears immediately after acute CO poisoning .The degrees of injury changes over time .Nogo-A mRNA expresses in normal corpus callosum , and it is up-regulated at 0 h and rose again on day 7 of CO poisoning .Our findings demonstrated that Nogo -A might be involved in demyelination injury after acute CO poisoning .
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