Abstract
Purpose: Prolonged denervation of skeletal muscles results in atrophy and poor recovery of motor function following delayed reinnervation. Electrical stimulation reduces denervation atrophy. We hypothesized that electrical stimulation of denervated extensor digitorum longus (EDL) muscles during a prolonged period between nerve axotomy and opportunity for reinnervation by motoneurons after nerve-repair would enhance the recovery of muscle mass, force and motor-function.
Methods: The EDL muscles of rats were denervated for 3.5 months by peroneal nerve axotomy, then repaired with an end-to-end neurorrhaphy, and allowed to recover for 6.5 months. During the period of denervation, some of the rats received a protocol of electrical stimulation that had previously been shown to dramatically attenuate the effects of denervation atrophy through 4 months. Other experimental groups included unoperated control muscles, denervated muscles, and axotomy followed immediately by nerve-repair. Final evaluations included walking track analysis, maximum force measured in situ by indirect stimulation of the nerve, and muscle mass.
Results: The hypothesis was not supported. Electrical stimulation during the period of denervation did not enhance recovery of muscle mass, force or motor function.
Conclusion: The primary factors that inhibited reinnervation and recovery following delayed reinnervation were not alleviated by the electrical stimulation during the period of muscle denervation.