Development of a novel force sensing system to measure the ground reaction force of rats with complete spinal cord injury

To date, the aim of spinal cord injury (SCI) researches in animals is to find the most effective treatment method which can lead to faster recovery. In order to evaluate if the method is effective, robust functional assessments are crucial. From the past to present, indicators to observe the recovery of the motor function in rodent SCI models are using human observance or the Basso, Beattie, and Bresnahan score (BBB score), force detection, and imaging approaches. Nevertheless, these indicators do not meet some requirements for a severe full transection injury case. The goal of this project is to develop a novel force sensing system for measuring the ground reaction force of rats with severe SCI. In total, this system was tested with 12 spinalized rats. Following a full transection at the T9-T10 level of the spinal cord in rats with a 2mm gap, a nanofiber scaffold containing Neurotrophin-3 (NT-3), as previously described, was implanted [1]. After 12 weeks of rehabilitative training, results showed that rats that underwent rehabilitation were able to gradually exert more force as compared to rats that did not undergo rehabilitation. At Week 6, the ground reaction force recorded in rats with rehabilitation was 0.8 ± 0.1 N in left limb and 0.75 ± 0.14 N in right limb. On the other hand, rats without rehabilitation exerted 0.52 ± 0.06 N in left limb and 0.47 ± 0.09 N in right limb. At Week 12, the force recorded in rehabilitated rats increased to 1.43 ± 0.13 N in left limb and 1.28 ± 0.17 N in right limb whereas in rats without rehabilitation, the force recorded was only 0.74 ± 0.12 N in left limb and 0.54 ± 0.11 N in right limb. These results not only showed that rehabilitation enhanced recovery of motor function, but also demonstrated the viability of measuring the ground reaction force applied by the rats as an assessment for a full spinal cord transection injury model.