Affiliations: Department of Biomedical Engineering, University of
Michigan, Ann Arbor, MI, USA | Department of Surgery, University of Michigan, Ann
Arbor, MI, USA | Department of Molecular & Integrative
Physiology, Ann Arbor, MI, USA | Department of Biomedical Engineering, University of
North Carolina, Chapel Hill, NC, USA
Note: [] Corresponding author: John A. Faulkner, Ph.D., Room 2035,
Biomedical Science Research Building, 109 Zina Pitcher Place, University of
Michigan, Ann Arbor, MI 48109-2200, USA. Tel.: +1 734 764 4378; Fax: +1 734 615
3292; E-mail: jafaulk@umich.edu
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.
