Effects of electrical stimulation and gonadal steroids on rat facial nerve regenerative properties

Nijee Sharma, Lisa Coughlin, Ryan G. Porter, Lisa Tanzer, Robert D. Wurster, Sam J. Marzo, Kathryn J. Jones, Eileen M. Foecking

Research output: Contribution to journalArticle

29 Scopus citations


Purpose: The neurotherapeutic effects of nerve electrical stimulation and gonadal steroids have independently been demonstrated. The purpose of this study was to investigate the therapeutic potential of a combinatorial treatment strategy of electrical stimulation and gonadal steroids on peripheral nerve regeneration. Methods: Following a facial nerve crush axotomy in gonadectomized adult male rats, testosterone propionate (TP), dihydrotestosterone (DHT), or estradiol (E-{2}) was systemically administered with/without daily electrical stimulation of the proximal nerve stump. Facial nerve outgrowth was assessed at 4 and 7 days post-axotomy using radioactive labeling. Results: Administration of electrical stimulation alone reduced the estimated delay in sprout formation but failed to accelerate the overall regeneration rate. Conversely, TP treatment alone accelerated the regeneration rate by ∼10% but had no effect on the sprouting delay. Combining TP with electrical stimulation, however, maintained the enhanced rate and reduced the sprouting delay. DHT treatment alone failed to alter the regeneration rate but combining it with electrical stimulation increased the rate by 10%. E-{2} treatment alone increased the regeneration rate by ∼5% but with electrical stimulation, there was no additional effect. Conclusions: Electrical stimulation and gonadal steroids differentially enhanced regenerative properties. TP, an aromatizable androgen, augmented regeneration most, suggesting a synergism between androgenic and estrogenic effects. Therapeutically, combining electrical stimulation with gonadal steroids may boost regenerative properties more than the use of either treatment alone.

Original languageEnglish (US)
Pages (from-to)633-644
Number of pages12
JournalRestorative Neurology and Neuroscience
Issue number6
StatePublished - Dec 1 2009
Externally publishedYes


  • Electrical stimulation
  • Gonadal steroids
  • Peripheral nerve injury
  • Regeneration

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience
  • Clinical Neurology

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  • Cite this

    Sharma, N., Coughlin, L., Porter, R. G., Tanzer, L., Wurster, R. D., Marzo, S. J., Jones, K. J., & Foecking, E. M. (2009). Effects of electrical stimulation and gonadal steroids on rat facial nerve regenerative properties. Restorative Neurology and Neuroscience, 27(6), 633-644. https://doi.org/10.3233/RNN-2009-0489