Motoneuron loss associated with chronic locomotion impairments after spinal cord contusion in the rat
Motoneuron loss associated with chronic locomotion impairments after spinal cord contusion in the rat
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DOI：
10.1089/neu.2005.22.544
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发表时间：
2005-05-01
影响因子：
4.2
通讯作者：
Nieto-Sampedro, M
中科院分区：
文献类型：
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作者：
Collazos-Castro, JE;Soto, VM;Nieto-Sampedro, M
有关脊髓损伤后缺陷的性质和适应机制的信息对于设计促进功能恢复的策略至关重要。通过三维运动学分析对轻度颈(C7)或中度腰(L2)脊髓挫伤后6个月自由行走大鼠的运动损伤和代偿进行量化。在C7挫伤后，动物的肘关节伸展和腕关节活动减少，而L2挫伤后膝关节伸展减少是主要的损害。在这两种情况下，由于站立阶段较长，步行周期的持续时间增加，前进速度降低。组织学显示可复制的病变延伸到大约一个脊髓节段。在横断面上，病变累及中央灰质和邻近的轴突，包括皮质脊髓背束，但部分保留了腹外侧束。用HRP神经暴露或肌肉注射氨基二丁二胺逆行追踪运动神经元表明，C7挫伤导致大约40%的肱三头肌运动神经元丢失，而L2挫伤后大约30%的股四头肌运动神经元丢失。这些结果显示了脊髓扩大不完全损伤后的永久性缺陷，并提示运动神经元的丢失是导致其产生的原因之一。
Information on the nature of deficits and adaptive mechanisms occurring after spinal cord injury is essential to the design of strategies for promoting functional recovery. Motor impairments and compensations were quantified by three-dimensional kinematic analysis in freely walking rats, 6 months after mild cervical (C7) or moderate lumbar (L2) spinal cord contusion. After C7 contusion, the animals showed reduced elbow extension and wrist movement, whereas reduced knee extension was the main impairment after L2 contusion. In both cases, the duration of the walking cycle increased and forward velocity was reduced due to a longer stance phase. Histology revealed reproducible lesions extending approximately to one spinal cord segment. In the transverse plane, the lesion involved the central gray matter and adjacent axons, including the dorsal corticospinal tract, but partially spared the ventrolateral tracts. Retrograde motoneuron tracing by nerve exposure to HRP or intramuscular injection of aminostilbamidine demonstrated that C7 contusion caused the loss of approximately 40% of triceps brachii motoneurons, whereas approximately 30% of quadriceps femoris motoneurons were lost after L2 contusion. These results demonstrate permanent deficits after incomplete lesions at the spinal cord enlargements and suggest that motoneuron loss contributes to their production.