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Differential regulation of cytoskeletal gene expression in hamster facial motoneurons: Effects of axotomy and testosterone treatment
Author(s) -
Jones Kathryn J.,
Storer Paul D.,
Drengler Susan M.,
Oblinger Monica M.
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19990915)57:6<817::aid-jnr6>3.0.co;2-q
Subject(s) - axotomy , testosterone propionate , facial nerve , testosterone (patch) , endocrinology , medicine , biology , hamster , silastic , microbiology and biotechnology , regeneration (biology) , androgen , anatomy , hormone
We have previously demonstrated that systemic administration of testosterone increases the rate of axonal regeneration following facial nerve crush in adult male hamsters. In the present study, the molecular mechanisms by which androgens could enhance axonal regeneration were examined at a cellular level. Specifically, the following question was addressed using quantitative in situ hybridization with cDNA probes complementary to βII, and α1 tubulin mRNAs: Does exogenous testosterone augment axotomy‐induced changes in tubulin mRNA expression in hamster facial motoneurons (FMN)? Castrated adult male hamsters were subjected to right facial nerve severance, with the left side serving as internal control. One‐half of the animals received testosterone replacement in the form of subcutaneously implanted silastic capsules containing crystalline testosterone propionate, and the other half were implanted with blank capsules immediately following the axotomy. Postoperative survival times from 2–14 days were examined. Axotomy alone resulted in a significant increase in the levels of both βII and α1 tubulin mRNAs in facial motor neurons between 2–14 days after injury. Administration of testosterone selectively augmented the axotomy‐induced increases in βII‐tubulin, but not α1 tubulin, mRNA, levels at 7 and 14 days post axotomy. These results demonstrating an effect of testosterone in altering the neuronal cytoskeletal response to axotomy suggest that testosterone may enhance the regenerative properties of motor neurons via molecular mechanisms that involve selective alterations of the neuronal cytoskeleton. J. Neurosci. Res. 57:817–823, 1999. © 1999 Wiley‐Liss, Inc.