Gonadal steroid attenuation of developing hamster facial motoneuron loss by axotomy

Equal efficacy of testosterone, dihydrotestosterone, and 17-β estradiol

Christopher B. Huppenbauer, Lisa Tanzer, Lydia L. DonCarlos, Kathryn Jones

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

In the hamster facial nerve injury paradigm, we have established that androgens enhance both functional recovery from facial nerve paralysis and the rate of regeneration in the adult, through intrinsic effects on the nerve cell body response to injury and via an androgen receptor (AR)-mediated mechanism. Whether these therapeutic effects of gonadal steroids encompass neuroprotection from axotomy-induced cell death is the focus of the present study. Virtually 100% of adult hamster facial motoneurons (FMNs) survive axotomy at the stylomastoid foramen (SMF), whereas, before postnatal day 15 (P15), developing FMNs undergo substantial axotomy-induced cell death. The first part of the present study focuses on determining when ARs are first expressed in developing hamster FMNs. Using AR immunocytochemistry, it was found that males express ARs by P2 and females by P4, which is the earliest demonstration of AR expression in mammalian motoneurons reported thus far in the literature. The second half examines the neuroprotective effects of testosterone propionate, 17-β estradiol, and dihydrotestosterone on FMNs of P7 hamsters after facial nerve transection at the SMF. The results demonstrate that androgens and estrogens are equally able to rescue ∼20% of FMNs from axotomy-induced cell death, with the effects permanent. This study is the first to investigate the effects of both androgens and estrogens on axotomy-induced cell death in one system and, with our previously published work, to validate the hamster FMN injury paradigm as a model of choice in the investigation of both neurotherapeutic and neuroprotective actions of gonadal steroids.

Original languageEnglish (US)
Pages (from-to)4004-4013
Number of pages10
JournalJournal of Neuroscience
Volume25
Issue number16
DOIs
StatePublished - Apr 20 2005
Externally publishedYes

Fingerprint

Axotomy
Dihydrotestosterone
Motor Neurons
Cricetinae
Testosterone
Estradiol
Steroids
Androgen Receptors
Cell Death
Androgens
Facial Nerve
Estrogens
Facial Nerve Injuries
Facial Injuries
Testosterone Propionate
Facial Paralysis
Neuroprotective Agents
Therapeutic Uses
Regeneration
Immunohistochemistry

Keywords

  • Androgen receptor
  • Development
  • Dihydrotestosterone
  • Estrogen
  • Motoneuron
  • Peripheral nerve injury
  • Testosterone

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Gonadal steroid attenuation of developing hamster facial motoneuron loss by axotomy : Equal efficacy of testosterone, dihydrotestosterone, and 17-β estradiol. / Huppenbauer, Christopher B.; Tanzer, Lisa; DonCarlos, Lydia L.; Jones, Kathryn.

In: Journal of Neuroscience, Vol. 25, No. 16, 20.04.2005, p. 4004-4013.

Research output: Contribution to journalArticle

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