Delayed rehabilitation with task-specific therapies improves forelimb function after a cervical spinal cord injury

Purpose: The effect of activity based therapies on restoring forelimb function in rats was evaluated when initiated one month after a cervical spinal cord injury. Methods: Adult rats received a unilateral over-hemisection of the spinal cord at C4/5, which interrupts the right side of the spinal cord and the dorsal columns bilaterally, resulting in severe impairments in forelimb function with greater impairment on the right side. One month after injury rats were housed in enriched housing and received daily training in reaching, gridwalk, and CatWalk. A subset of rats received rolipram for 10 days to promote axonal plasticity. Rats were tested weekly for six weeks for reaching, elevated gridwalk, CatWalk, and forelimb use during vertical exploration. Results: Rats exposed to enriched housing and daily training significantly increased the number of left reaches and pellets grasped and eaten, reduced the number of right forelimb errors on the gridwalk, increased right forelimb use during vertical exploration, recovered more normal step cycles, and reduced their hindlimb base of support on the CatWalk compared to rats in standard cages without daily training. Conclusions: Delayed rehabilitation with enriched housing and daily forelimb training significantly improved skilled, sensorimotor, and automatic forelimb function together after cervical spinal cord injury.