Electrical stimulation of nerve regeneration in the rat: functional evaluation by a twitch tension method

The effect of D.C. electrical fields on in vivo nerve regeneration following rat sciatic nerve transection was assessed by a toe-twitch tension method for motor recovery. Two groups for baseline comparisons received either a nerve transection and a neutral battery implant or a nerve crush and no implant. Two treatment groups each received a nerve transection and an implant delivering either cathodal (–10 μA) or anodal (+10 μA) current via electrodes positioned on either side of the transection site. The contralateral nerve was exposed but not given a lesion. The functional recovery was assessed at weekly intervals by comparing the amplitude and area of the twitch tension curves on both sides, expressed as a ratio (index of motor recovery = IMR). By 28–35 days postoperative (dpo) the crushed/untreated group had mean IMR values not significantly different than the preoperative values. The transected/neutral group appeared to have the worst recovery throughout the study. Compared to these two groups, both the cathodal and anodal treatment groups with a transected nerve showed intermediate IMR values, but by 63 dpo the group differences were less. These results indicate that following a nerve transection lesion steady D.C. electrical fields may temporarily enhance the early functional recovery of motor nerve regeneration compared to conventional nerve repair alone.