Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA.
J Neurotrauma. 2011 Dec;28(12):2405-16. doi: 10.1089/neu.2010.1660. Epub 2011 Aug 8.
Body-weight-supported treadmill training (BWSTT)-related locomotor recovery has been shown in spinalized animals. Only a few animal studies have demonstrated locomotor recovery after BWSTT in an incomplete spinal cord injury (SCI) model, such as contusion injury. The contribution of spared descending pathways after BWSTT to behavioral recovery is unclear. Our goal was to evaluate locomotor recovery in contused rats after BWSTT, and to study the role of spared pathways in spinal plasticity after BWSTT. Forty-eight rats received a contusion, a transection, or a contusion followed at 9 weeks by a second transection injury. Half of the animals in the three injury groups were given BWSTT for up to 8 weeks. Kinematics and the Basso-Beattie-Bresnahan (BBB) test assessed behavioral improvements. Changes in Hoffmann-reflex (H-reflex) rate depression property, soleus muscle mass, and sprouting of primary afferent fibers were also evaluated. BWSTT-contused animals showed accelerated locomotor recovery, improved H-reflex properties, reduced muscle atrophy, and decreased sprouting of small caliber afferent fibers. BBB scores were not improved by BWSTT. Untrained contused rats that received a transection exhibited a decrease in kinematic parameters immediately after the transection; in contrast, trained contused rats did not show an immediate decrease in kinematic parameters after transection. This suggests that BWSTT with spared descending pathways leads to neuroplasticity at the lumbar spinal level that is capable of maintaining locomotor activity. Discontinuing training after the transection in the trained contused rats abolished the improved kinematics within 2 weeks and led to a reversal of the improved H-reflex response, increased muscle atrophy, and an increase in primary afferent fiber sprouting. Thus continued training may be required for maintenance of the recovery. Transected animals had no effect of BWSTT, indicating that in the absence of spared pathways this training paradigm did not improve function.
体重大承重跑台训练（BWSTT）相关的运动恢复已在脊髓切断动物中得到证实。只有少数动物研究表明，BWSTT 后在不完全性脊髓损伤（SCI）模型中存在运动恢复，例如挫伤损伤。BWSTT 后保留的下行通路对行为恢复的贡献尚不清楚。我们的目标是评估 BWSTT 后挫伤大鼠的运动恢复，并研究 BWSTT 后脊髓可塑性中保留的通路的作用。48 只大鼠接受挫伤、横切或挫伤后 9 周再接受第二次横切损伤。三组损伤动物中的一半接受了长达 8 周的 BWSTT。运动学和 Basso-Beattie-Bresnahan（BBB）测试评估了行为改善情况。Hoffmann 反射（H 反射）率抑制特性、比目鱼肌质量和初级传入纤维的发芽变化也进行了评估。BWSTT 挫伤动物表现出运动恢复加快、H 反射特性改善、肌肉萎缩减少和小口径传入纤维发芽减少。BWSTT 未改善 BBB 评分。未经训练的挫伤大鼠在横切后立即出现运动学参数下降；相比之下，经过训练的挫伤大鼠在横切后并没有立即出现运动学参数下降。这表明，保留下行通路的 BWSTT 可导致腰脊髓水平的神经可塑性，从而维持运动活动。在训练过的挫伤大鼠中，在横切后停止训练会在 2 周内消除改善的运动学，并导致改善的 H 反射反应逆转、肌肉萎缩增加和初级传入纤维发芽增加。因此，可能需要持续训练来维持恢复。横切动物对 BWSTT 没有影响，表明在没有保留通路的情况下，这种训练方案不能改善功能。
