Tenascin-R inhibits the growth of optic fibers in vitro but is rapidly eliminated during nerve regeneration in the salamander Pleurodeles waltl

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Catherina G. Becker - , University of Hamburg, University of California at Irvine (Author)
  • Thomas Becker - , University of Hamburg, University of California at Irvine (Author)
  • Ronald L. Meyer - , University of California at Irvine (Author)
  • Melitta Schachner - , University of Hamburg (Author)

Abstract

Tenascin-R is a multidomain molecule of the extracellular matrix in the CNS with neurite outgrowth inhibitory functions. Despite the fact that in amphibians spontaneous axonal regeneration of the optic nerve occurs, we show here that the molecule appears concomitantly with myelination during metamorphosis and is present in the adult optic nerve of the salamander Pleurodeles waltl by immunoblots and immunohistochemistry. In vitro, adult retinal ganglion cell axons were not able to grow from retinal explants on a tenascin-R substrate or to cross a sharp substrate border of tenascin-R in the presence of laminin, indicating that tenascin-R inhibits regrowth of retinal ganglion cell axons. After an optic nerve crush, immunoreactivity for tenascin-R was reduced to undetectable levels within 8 d. Immunoreactivity for the myelin-associated glycoprotein (MAG) was also diminished by that time. Myelin was removed by phagocytosing cells at 8-14 d after the lesion, as demonstrated by electron microscopy. Tenascin-R immunoreactivity was again detectable at 6 months after the lesion, correlated with remyelination as indicated by MAG immunohistochemistry. Regenerating axons began to repopulate the distal lesioned nerve at 9 d after a crush and grew in close contact with putative astrocytic processes in the periphery of the nerve, close to the pia, as demonstrated by anterograde tracing. Thus, the onset of axonal regrowth over the lesion site was correlated with the removal of inhibitory molecules in the optic nerve, which may be necessary for successful axonal regeneration in the CNS of amphibians.

Details

Original languageEnglish
Pages (from-to)813-827
Number of pages15
JournalJournal of Neuroscience
Volume19
Issue number2
Publication statusPublished - 15 Jan 1999
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 9880601

Keywords

ASJC Scopus subject areas

Keywords

  • Amphibians, CNS injury, Extracellular matrix, Optic nerve, Retinotectal system, Urodeles