The Impact of Midcervical Contusion Injury on Diaphragm Muscle Function
The Impact of Midcervical Contusion Injury on Diaphragm Muscle Function
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DOI：
10.1089/neu.2015.4054
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发表时间：
2016-03-01
影响因子：
4.2
通讯作者：
Mantilla, Carlos B.
中科院分区：
文献类型：
--
作者：
Alvarez-Argote, Santiago;Gransee, Heather M.;Mantilla, Carlos B.
颈中挫伤破坏同侧向膈运动神经元的下行兴奋性球脊髓投射，影响通气。我们假设单侧C3挫伤与C5挫伤对膈活动的影响不同，反映了更多颅脑损伤的同侧下行兴奋性驱动更明显地破坏膈运动池的尾端节段。在单侧挫伤（100 kDynes）损伤后14天，评估膈肌运动神经元计数和膈肌单个神经肌肉连接处（NMJ）失神经支配的证据。分别于损伤前、损伤后3、7、14天测量全身体积脉搏图和慢性膈肌肌电图。两处挫伤造成的空洞大小相似。C3挫伤导致同侧膈运动神经元损失39 +/- 13%，而C5挫伤后损失13 +/- 21% （p = 0.003）。颈椎挫伤导致膈肌失神经支配（C3挫伤：17 +/- 4%；C5挫伤：7 +/- 4%；p = 0.047）。断神经模式显示膈肌的节段性神经支配，C3挫伤后腹侧断神经较多，C5挫伤后背侧断神经较多。总体而言，C3或C5挫伤后膈根均方肌电活动未发生同侧改变，但仅在损伤后第一天C3挫伤后对侧增加（相似率为11%）（p = 0.026）。同样，在呼吸暂停或暴露于缺氧(10% O-2) -高碳酸血症（5% CO2）期间，在损伤后的任何时间呼吸参数均无显著变化。单侧颈中挫伤对通气行为的损害最小，尽管膈运动神经元丢失和膈肌去神经支配。
Midcervical contusion injuries disrupt descending ipsilateral excitatory bulbospinal projections to phrenic motoneurons, compromising ventilation. We hypothesized that a unilateral contusion injury at C3 versus C5 would differentially impact phrenic activity reflecting more prominent disruption of ipsilateral descending excitatory drive to more caudal segments of the phrenic motor pool with more cranial injuries. Phrenic motoneuron counts and evidence of diaphragm muscle denervation at individual neuromuscular junctions (NMJ) were evaluated at 14 days post-injury after unilateral contusion injury (100 kDynes). Whole body plethysmography and chronic diaphragm EMG were measured before the injury and at 3, 7, and 14 days post-injury. Contusion injuries at either level resulted in a similarly sized cavity. C3 contusion resulted in loss of 39 +/- 13% of ipsilateral phrenic motoneurons compared with 13 +/- 21% after C5 contusion (p = 0.003). Cervical contusion injuries resulted in diaphragm muscle denervation (C3 contusion: 17 +/- 4%; C5 contusion: 7 +/- 4%; p = 0.047). The pattern of denervation revealed segmental innervation of the diaphragm muscle, with greater denervation ventrally after C3 contusion and dorsally after C5 contusion. Overall, diaphragm root mean square electromyography activity did not change ipsilaterally after C3 or C5 contusion, but increased contralaterally (similar to 11%) after C3 contusion only on the first day post-injury (p = 0.026). Similarly, there were no significant changes in breathing parameters during eupnea or exposure to hypoxia (10% O-2) - hypercapnia (5% CO2) at any time post-injury. Unilateral midcervical contusions minimally impair ventilatory behaviors despite phrenic motoneuron loss and diaphragm muscle denervation.