Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada; Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.
Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada; Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada; Department of Physical Therapy, University of Alberta, Edmonton, AB, Canada.
Behav Brain Res. 2022 Mar 26;422:113731. doi: 10.1016/j.bbr.2021.113731. Epub 2021 Dec 31.
Animal models of cervical spinal cord injury (SCI) have frequently utilized partial transection injuries to evaluate plasticity promoting treatments such as rehabilitation training of skilled reaching and grasping tasks. Though highly useful for studying the effects of cutting specific spinal tracts that are important for skilled forelimb motor function, cervical partial-transection SCI-models underappreciate the extensive spread of most human SCIs, thus offering poor predictability for the clinical setting. Conversely, moderate cervical contusion SCI models targeting the spinal tracts important for skilled reaching and grasping can better replicate the increased size of most human SCIs and are often considered more clinically relevant. However, it is unknown whether animals with moderate cervical contusion SCIs that damage key spinal motor tracts can train in skilled reaching and grasping tasks. In this study, we quantify the impact of injury size and distribution on recovery in a skilled motor task called the single pellet reaching, grasping and retrieval (SPRGR) task in rats with cervical unilateral contusion injuries (UCs), and compare to rats with a partial transection SCIs (i.e., dorsolateral quadrant transection; DLQ). We found that UCs damage key tracts important for performing skilled motor tasks, similar to DLQs, but UCs also produce more extensive grey matter damage and more ventral white matter damage than DLQs. We also compared forelimb functionality at 1, 3, and 5 weeks of rehabilitative motor training between trained and untrained rats and found a more severe drop in SPRGR performance than in DLQ SCIs. Nevertheless, despite more severe injuries and initially low SPRGR performance, rehabilitative training for contusion animals resulted in significant improvements in SPRGR performance and proportionally more recovery than DLQ rats. Our findings show that rehabilitative motor training can facilitate considerable amounts of motor recovery despite extensive spinal cord damage, especially grey matter damage, thus supporting the use of contusion or compression SCI models and showing that ventral grey and white matter damage are not necessarily detrimental to recovery after training.
动物的颈脊髓损伤 (SCI) 模型经常使用部分横切损伤来评估促进可塑性的治疗方法，如熟练的上肢运动和抓握任务的康复训练。尽管这种方法对于研究对熟练前肢运动功能重要的特定脊髓束的切割效果非常有用，但颈部分离 SCI 模型低估了大多数人类 SCI 的广泛扩散，因此对临床环境的预测性较差。相反，针对熟练上肢运动和抓握重要的脊髓束的中度颈挫伤 SCI 模型可以更好地复制大多数人类 SCI 的增大，通常被认为更具有临床相关性。然而，目前还不清楚是否具有中度颈挫伤 SCI 的动物能够在熟练的上肢运动和抓握任务中进行训练，这些 SCI 损伤了关键的脊髓运动束。在这项研究中，我们量化了损伤大小和分布对熟练运动任务（称为单颗粒取物、抓取和检索 (SPRGR) 任务）恢复的影响，该任务在颈单侧挫伤损伤 (UC) 的大鼠中进行，并与部分横切 SCI（即背外侧象限横切；DLQ）的大鼠进行比较。我们发现，UC 损伤了执行熟练运动任务的关键束，与 DLQ 相似，但 UC 也比 DLQ 产生更多的灰质损伤和更腹侧的白质损伤。我们还比较了在接受康复运动训练的 1、3 和 5 周时，训练和未训练大鼠的前肢功能，发现 SPRGR 表现比 DLQ SCI 下降更为严重。尽管损伤更严重，SPRGR 表现最初较低，但挫伤动物的康复训练导致 SPRGR 表现显著改善，恢复比例高于 DLQ 大鼠。我们的研究结果表明，康复运动训练可以促进大量的运动恢复，尽管脊髓损伤严重，尤其是灰质损伤严重，但支持使用挫伤或压迫 SCI 模型，并表明腹侧灰质和白质损伤在训练后不一定不利于恢复。
