大鼠不同类型臂丛根性损伤后脊髓运动神经元NOS的表达

目的 研究成年大鼠不同类型臂丛损伤后脊髓运动神经元一氧化氮合酶（NOS）表达与神经元死亡之间的关系。方法 选用76只健康成年SD大鼠，分别造成臂丛神经根性切断伤与根性撕脱伤，于损伤后不同时间观察脊髓前角运动神经元的存活率，以及NOS在脊髓前角运动神经元中的表达情况。结果 臂丛神经根性切断伤后，损伤侧脊髓前角运动神经元无明显死亡，且未见NOS表达。臂丛神经根性撕脱伤后1周，损伤侧脊髓前角运动神经元数目开始减少，并出现NOS阳性表达。之后随着NOS阳性神经元增多，神经元死亡率也增加，6周后神经元数目基本维持稳定而NOS阳性神经元逐渐减少消失。结论 臂丛神经根性撕脱伤后，NOS参与损伤后脊髓运动神经元死亡，或在运动神经元死亡中起重要作用。

NOS Expression of Spinal Motoneurons after Different Brachial Plexus Root Injuries

Objective\ To investigate the relationship of nitric oxide synthase(NOS) expression and motoneurons damage after different brachial plexus root injuries.\ Methods\ 76 adult healthy SD rats were performed as the model of brachial plexus root avulsion or root axotomy.\ The spinal region was dissected for motoneuron counting and the expression of NOS was analyzed 1, 3 d, 1, 2, 3, 4, 6, 9, 12 week respectively after injury.\ Results\ Cell damage and NOS expression of spinal motoneurons occurred at 1 week after root avulsion.\ The motoneuron damage increased accordingly with the increase of NOS expression.\ 6 weeks later the number of NOS positive motoneurons was obviously decreased with no more motoneurons loss.\ However, no significant motoneuron damage and no NOS\|positive motoneurons were observed after spinal root axotomy.\ Conclusion\ NOS expression has been induced after brachial plexus root avulsion and is coincident with cell damage of spinal motoneurons.\ That NO may play important role in motoneurons damage.