Electrical muscle stimulation increases early reinnervation following nerve injury and immediate repair

Treating partially or completely denervated muscle following nerve injury using electrical muscle stimulation has been met with much controversy. Previous studies have shown that chronic electrical muscle stimulation or neuromuscular activity leads to impaired reinnervation of muscle end plates. In this study we investigated the use of a moderate stimulation paradigm delivered daily over a 2 week period and the effects on functional recovery and reinnervation. Rat gastrocnemius muscle was denervated by complete tibial nerve transection and immediately repaired using epineurial sutures. Electrical muscle stimulation was carried out 5 days per week in 1 hour sessions. Our results show that numbers of motoneurons reinnervating muscle and reinnervated endplates were significantly higher in animals that received daily muscle stimulation compared to those without stimulation. Other functional measurements such as muscle force, weight, and contractile properties were no different between groups. Our results provide evidence that the improved reinnervation may be due to antidromic depolarization of axons proximal to the repair site.