Testosterone regulation of the regenerative properties of injured rat sciatic motor neurons

K. A. Kujawa, J. M. Jacob, Kathryn Jones

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

We have previously demonstrated that systemic administration of testosterone differentially regulates the regenerative properties of injured hamster facial motor neurons, which are androgen receptor-containing cranial motor neurons. In this investigation, the hypothesis that testosterone alters the regenerative properties of rat sciatic motor neurons, which are androgen receptor-containing spinal motor neurons, was tested using fast axonal transport of radioactively labeled proteins to assess sciatic nerve regeneration. Adult castrated male rats were subjected to crush axotomy of the sciatic nerve at the level of the gemelli tendons (mid-thigh). One-half of the axotomized animals received subcutaneous implants of testosterone propionate (TP), with the remainder of the animals sham implanted with blank capsules. The outgrowth distances of the leading axons were measured at 5, 6, 7, and 11 days postoperative. Linear regression analysis was accomplished, with the slope of the line representing the regeneration rate and the x- intercept the initial delay of sprout formation. Systemic administration of testosterone resulted in a 13% increase in the rate of regeneration, relative to the control, -TP group. Outgrowth distances were significantly increased in the +TP group only in the later stages of regeneration. However, TP did not shorten the delay in sprout formation in regenerating sciatic motor neurons, but instead produced a small prolongation in the delay time. This pattern of hormonal regulation of the regenerative properties of spinal motoneurons is similar to that previously found in cranial motoneurons. The prolongation of the initial delay may have been a factor in the lack of significant outgrowth distances during the early stages of regeneration. The magnitude of the effects of TP on male rat sciatic motor neurons are less pronounced than in male hamster facial motor neurons, but quite similar to those effects observed in female hamster facial motor neurons. Why this is the case is not known, but may be related to a number of factors discussed in the text.

Original languageEnglish (US)
Pages (from-to)268-273
Number of pages6
JournalJournal of Neuroscience Research
Volume35
Issue number3
StatePublished - 1993
Externally publishedYes

Fingerprint

Motor Neurons
Testosterone
Testosterone Propionate
Regeneration
Cricetinae
Androgen Receptors
Sciatic Nerve
Axotomy
Nerve Regeneration
Axonal Transport
Thigh
Tendons
Capsules
Axons
Linear Models
Regression Analysis

Keywords

  • androgens
  • axotomy
  • peripheral neuron
  • sciatic motoneuron
  • testosterone
  • trophic factor

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Testosterone regulation of the regenerative properties of injured rat sciatic motor neurons. / Kujawa, K. A.; Jacob, J. M.; Jones, Kathryn.

In: Journal of Neuroscience Research, Vol. 35, No. 3, 1993, p. 268-273.

Research output: Contribution to journalArticle

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