犬马尾神经受压后腰骶髓中一氧化氮合酶活性与神经细胞凋亡的相关性

目的：研究马尾神经受压后一氧化氮合酶（NOS）活性变化与腰骶髓神经细胞凋亡的关系。方法：将27只健康家犬随机分为3组：A组21只，水囊置于椎管内并注水加压制成马尾神经压迫模型（马尾神经压迫组）；B组3只，置入水囊但未注水加压（假手术组）；C组3只（正常组）。A组再分为7组，即马尾神经持续受压4h、8h、12h、24h、48h、72h和168h组（n=3）。检测各组腰骶髓组织中的NOS活性变化，用TUNEL法标记凋亡神经元和神经胶质细胞，光镜（HE染色）和透射电镜观察细胞形态学改变。结果：B组和C组腰骶髓神经细胞形态未见异常，A组光镜及电镜观察结果均提示神经细胞发生凋亡。B组和C组未见凋亡神经元，A组于压迫后12h可见凋亡神经元，24～48h神经元凋亡最多。B组与C组腰骶髓组织中NOS活性比较无显著性差异（P〉0．05），A组于压迫12h后，NOS活性即明显增高，与B组和C组比较有显著性差异（P〈0．05），24～48h达到高峰，72h后开始下降。结论：犬马尾神经受压后腰骶髓组织中NOS活性增高，与相应神经元凋亡存在正相关。

Correlation between the activity of NOS and neuron apoptosis after cauda equina nerve compression in dogs

Objective:To study the relationship between the activity of NOS and neuron apoptosis of lumbosacral marrow after caudal equine nerve compression in dogs.Method:27 healthy dogs were randomly divided into three groups:the compression caudal equine nerve group(n=21);the fake operation group(n=3);and the normal group(n=3).Furthermore,the test group was randomly divided into 7 subgroups,namely,with caudal equine nerve compressed for 4h,8h,12h,24h,48h,72h and 168h(n=3)respectively.The fake operation group was control group.The caudal equine nerve compressed model made was constructed by putting a hydrosac in vertebral canal.The activity of NOS was detected,and the apoptosis nerve cells were labeled by TUNEL marking method.The morphology changes of cells were observed by microscopic examination(HE staining)and transmission electron microscope.Result:No abnormal morphological change of cells was observed in fake operation group and the normal group,but apoptosis of cells in test group were observed under microscopic examination and transmission electron microscope.No apoptosis nerve cells labeled by TUNEL were observed in both the fake operation group and the normal group,the apoptosis neuron were observed in the 12h subgroup in group A,and reached peak between 24h and 48h.No distinct difference in the activity of NOS was detected between the normal group and the fake group(the control group)(P>0.05).The activity of NOS increased obviously 12h after being pressed in group A,which had significant difference compared with group B and C(P<0.05),and activity of NOS reached peak at 24-48h,while decreasing after 72h.Conclusion:There is positive correlation between the activity of NOS and apoptosis of nerve cells in lumbosacral marrow of caudal equine being compressed.