The short-term effects of delayed application of electric fields in the damaged rodent spinal cord.

Previous studies have indicated that the application of electrical fields to the contused rat spinal cord could result in a partial return of function within 3 weeks after injury/treatment. Whether similar functional recovery could be established after a delay in the treatment was investigated. Rat spinal cords were contused and allowed to recover untreated for 10 days. At that time, a stimulator delivering 3 microA of direct current was applied to the dorsal portion of the cord such that the cathode was oriented either rostral or caudal to the lesion. Inactive stimulators were also used as controls. Rats were then assessed behaviorally and clinically at weekly intervals up to 3 weeks on an inclined plane and then killed for histological assessments. The results indicate that both the "cathode rostral" and "anode rostral" groups performed statistically significantly better on the inclined plane than the "no current" group. The cathode rostral and anode rostral group animals also demonstrated superior motor abilities. The number of axons in the dorsal funiculi rostral to the lesion in the actively treated groups were also statistically significantly greater than no current controls. The cathode rostral group animals demonstrated a greater number of viable neuronal cell bodies near the site of the lesion. These data suggest that electric fields may facilitate functional recovery and regeneration in the mammalian spinal cord, even after a delay in such treatment.