Task Practice with or without Cellular Transplantation Promotes Recovery of Reach-to Grasp Function after Cervical Spinal Cord Injury

Background and Purpose: Cervical spinal cord injury results in specific deficits in forelimb function. In the rat, lesions to the rubrospinal tract impair forelimb function despite the presence of an intact corticospinal tract. Both functional and anatomical recovery have been promoted by transplantation of neuronal and glial restricted precursors (NRP/GRP) following injury, and task-specific practice is used clinically to maximize recovery of function. We tested the hypothesis that combination therapy of daily task practice and NRP/GRP cell transplants will improve reach-to-grasp function. Methods: Forty-one adult female rats received a lesion to the right cervical dorsolateral funiculus. They were randomly divided into 4 groups for the study: Control (n=11), NRP/GRP Transplant (n=14), Task Practice (n=8), and Task Practice + NRP/GRP (n=8). All animals were assessed pre-injury and during weeks 1 and 8 postoperatively on two reach-to-grasp tests (Single Pellet and Staircase Reaching). Results: Task Practice + NRP/GRP and Task Practice groups achieved significant recovery of function in the Staircase Reaching test at week 8 of recovery. Analysis of individual kinematic elements from the Single Pellet Reaching test allows detailed quantitation of specific movements. While major differences were not observed in the Single Pellet Reaching, the Digits Open and Pronation qualitative component scores were higher in the Task Practice + NRP/GRP group compared to controls at 8 weeks post injury. Conclusions: While task practice improves recovery of forelimb function following incomplete spinal cord injury, combination therapy of daily task practice and cell transplantation practice did not result in superior recovery of reach-to-grasp function.