Effects of Swimming on Functional Recovery after Incomplete Spinal Cord Injury in Rats

Abstract

One of the most promising rehabilitation strategies for spinal cord injury is weight-supported treadmill training. This strategy seeks to re-train the spinal cord below the level of injury to generate a meaningful pattern of movement. However, the number of step cycles that can be accomplished is limited by the poor weight-bearing capability of the neuromuscular system after injury. We have begun to study swimming as a rehabilitation strategy that allows for high numbers of steps and a high step-cycle frequency in a standard rat model of contusive spinal cord injury. The purpose of the present study was to evaluate the effect of swimming as a rehabilitation strategy in rats with contusion injuries at T9. We used a swimming strategy with or without cutaneous feedback based on original work in the chick by Muir and colleagues. Adult female rats (n=27) received moderately-severe contusion injuries at T9. Walking and swimming performance were evaluated using the Open-Field Locomotor Scale (BBB; Basso et al., 1995) and a novel swimming assessment, the Louisville Swimming Scale (LSS). Rats that underwent swim-training with or without cutaneous feedback showed a significant improvement in hindlimb function during swimming compared to untrained animals. Rats that underwent swim-training without cutaneous feedback showed less improvement than those trained with cutaneous feedback. Rats in the non-swimming group demonstrated little improvement over the course of the study. All three groups showed the expected improvement in over-ground walking and had similar terminal BBB scores. These findings suggest that animals re-acquire the ability to swim only if trained and that cutaneous feedback improves the re-training process. Further, these data suggest that the normal course of recovery of over-ground walking following moderately-severe contusion injuries at T9 is the result of a re-training process.

Plasticity After Spinal Cord Injury: Relevance to Recovery and Approaches to Facilitate It

“…Not surprisingly, training in one task does not necessarily translate into improvements in another task [53][54][55][56]. Even more surprising are findings that training in one task can even have detrimental effects on another task.…”

Effects of telemetry EMG implants on hindlimb locomotor recovery in thoracic spinal contused rats.

“…Furthermore, the coordinated pattern index (CPI) was used to analyze coordination patterns regardless of weight support or dorsal stepping. were processed for spared white matter (SWM) quantification according to our standard protocol (Smith et al, 2006). We also delineated the ventral half of the epicenters to measure only the spared ventral fiber tracts which include the ventral lateral funiculus, Figure 6.…”

“…Past studies in our own lab have also been challenged by spontaneous recovery of locomotion in rats following SCI (Magnuson et al, 2005;Smith et al, 2006). As assessed by the BBB Open Field Locomotor Scale, a measure of hindlimb function during overground stepping (BBB; Basso et al, 1996), rats from injured (untrained) control groups achieved scores of 13-15 or 10-12 for moderate or moderately-severe injuries, respectively, and neither swim training nor shallow-water training improved BBB scores (Kuerzi et al, 2010;Magnuson et al, 2009;Smith et al, 2006).…”

“…As assessed by the BBB Open Field Locomotor Scale, a measure of hindlimb function during overground stepping (BBB; Basso et al, 1996), rats from injured (untrained) control groups achieved scores of 13-15 or 10-12 for moderate or moderately-severe injuries, respectively, and neither swim training nor shallow-water training improved BBB scores (Kuerzi et al, 2010;Magnuson et al, 2009;Smith et al, 2006). We first attempted to address the effects of in-cage retraining using a hindlimb immobilization model.…”

Estratégia terapêutica após contusão da medula espinhal: recuperação funcional e estabilidade cortical sensório-motora

“…Além das melhoras funcionais, foram observadas melhoras histológicas com diminuição das cavidades císticas e aumento do volume das substâncias branca e cinzenta residuais (Berrocal et al, 2007). Outro tipo de tratamento que tem sido investigado intensivamente pelo grupo de Magnunson é a natação em modelos experimentais de lesão medular (Smith et al, 2006;Magnunson et al, 2009;Smith et al, 2009). Esses trabalhos demonstraram que os animais treinados a nadar apresentam melhora deste comportamento depois da LM.…”