The effects of remaining axons on motoneuron survival and NOS expression following axotomy in the adult rat
The effects of remaining axons on motoneuron survival and NOS expression following axotomy in the adult rat
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DOI：
10.1159/000111214
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发表时间：
1997-05-01
影响因子：
2.9
通讯作者：
Wu, WT
中科院分区：
文献类型：
--
作者：
Gu, YM;Spasic, Z;Wu, WT
众所周知，在成年动物中，靶点切除或远端轴突切断不会导致脊髓中可检测到的运动神经元的丢失。本研究通过在距脊髓不同距离(分别为0、2、4、8 mm)的颈7脊神经行轴突切断术，观察残留轴突对运动神经元存活和一氧化氮合酶表达的影响。本研究的结果表明，如果离脊髓足够近，成人周围神经的轴突切断可以导致明显的脊髓运动神经元死亡。神经切断距离脊髓越近，运动神经元损失率越高。在距脊髓0 mm处切断轴突的动物中，运动神经元丢失最显著，这与一氧化氮合酶阳性运动神经元的最高百分比相一致。轴突离脊髓的距离从0 mm增加到4 mm时，运动神经元存活率增加，一氧化氮合酶阳性神经元百分率降低。当轴突切断点为4 mm及远端时，未见明显的运动神经元丢失或一氧化氮合酶阳性神经元。这些结果表明，成年大鼠脊髓运动神经元的存活在很大程度上取决于剩余轴突的长度。残留的轴突越长，运动神经元的存活越好。成年大鼠运动神经元存活所需轴突的最小长度似乎至少为4 mm。
It is well known that target removal or distal axotomy in adult animals results in no detectable loss of motoneurons in the spinal cord. By performing axotomy in the seventh cervical (C7) spinal nerve at different distances from the spinal cord (0, 2, 4, 8 mm respectively), this study examines the effects of the remaining axons on motoneuron survival as well as NOS expression. Results of the present study show that axotomy in adult peripheral nerve can induce significant spinal motoneuron death if axotomy is performed close enough to the spinal cord. The closer the axotomy to the spinal cord, the higher the rate of motoneuron loss was observed. The most significant motoneuron loss was found in animals with axotomy at 0 mm to the cord, which was coincident with the highest percent of NOS-positive motoneurons. The rate of survival of motoneurons increases and the percent of NOS-positive motoneurons decreases when the distance of the axotomy to the cord increases from 0 to 4 mm. No significant motoneuron loss nor NOS-positive motoneurons were observed when axotomy was performed at 4 mm and distally. These results indicate that the survival of spinal motoneurons in adult rat following axotomy is largely dependent on the length of the remaining axons. The longer the remaining axon: the better for motoneuron survival. The minimal length of axon for motoneuron survival in adult rat seems to be at least 4 mm.