Weak electric current accelerates motoneuron regeneration in the sciatic nerve of ten-month-old rats

When a weak direct current (DC) of 10 microA driven by an implantable device was applied to a crushed sciatic nerve in 9-10-month-old rats, regeneration was accelerated as assessed electrophysiologically. Rats underwent a sciatic nerve crush of the right leg and were randomly assigned to one of three groups: (i) Cathode Distal (CD); (ii) Sham Implant (SI); or (iii) No Implant (NI). On post-operative days 25-39 each rat received a measurement of evoked electromyograms (EMG) in the foot. In addition each rat received a behavioural test score (BTS). This BTS correlated well with the evoked EMG results showing the behavioural relevance of the EMG results. NI rats performed the same as SI in the evoked EMG procedure, but CD rats performed significantly better than both the control groups. The recovery period in the CD rats was 21% shorter than in either the sham-treated or untreated controls showing that weak DC can greatly enhance nerve regeneration in adult rats. This result was in contrast to previous work in younger rats where DC treatments had no effects. The discrepancy is discussed in relation to the slowing of regeneration in older rats.