2006 Ohio Student Research Forum

Abstract

The effect of weight-supported exercise on recovery of locomotor function after spinal cord contusion injury in the rat
Annemarie McCartney
Ohio State University
Department of Zoology
Mentor(s):Dr. Jacqueline Bresnahan, Dr. Michael Beattie
Contributers : Stephanie Beattie, Amy Tovar, Dr. Adam Ferguson

Moderate spinal cord contusion injury (SCI) in the rat results in locomotor deficits, including trunk instability and lack of forelimb-hindlimb coordination. Studies in human and animal paraplegics have demonstrated that treadmill training accelerates recovery of locomotion and increases function (Multon, et al, 2003), and our goal is to determine if using weight-support to increase hindlimb plantar placement increased recovery of locomotor function. Total weight support through simulated microgravity can induce adverse changes such as muscle atrophy and abnormal locomotion (Canu et al, 2005), so our experiment used voluntary exercise and moderate hindlimb unloading. Our goal is to develop a novel rehabilitation strategy for human SCI individuals to improve terminal performance and the rate of recovery after SCI, which would afford financial and quality-of-life improvements.

Open field pools of approximately 5 feet in diameter were constructed, two of which had elastic cords suspended from the ceiling above the center of the pools which connected to animal harnesses to provide weight-support. The apparatus was designed to allow the animals to choose their degree of weight-support, which increased with movement away from the center of the field. Female hooded Long Evans rats were familiarized with the pools, and subsequently a 12.5 gcm spinal cord contusion injury at T9-T10 was produced using the NYU device. At 72 hours post-injury the animals were divided into “tethered” (n = 4) and “untethered” (n = 4) groups, and voluntary exercise in harnesses 5 days/week was started 1 week post-injury, with the “tethered” animals receiving hindlimb weight-support. Spontaneous walking ability in an open field is analyzed at regular intervals by blinded observers using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale to assess recovery.
Previous studies have shown that locomotor recovery from moderate contusion injury plateaus around 7 weeks post-injury, and our experiment is currently 3 weeks post-injury. An ANOVA performed using SPSS 14.0 on BBB data collected from four time points shows a trend toward a rehabilitative effect of weight-support and suggests that the animals in the tethered group may be recovering more quickly, but the difference between the two groups is not significant at this stage of the experiment (p = 0.275).