PROLIFERATION OF NEUROGLIAL CELL-LINES IN THE DEGENERATING OPTIC-NERVE OF YOUNG-RATS - A AUTORADIOGRAPHIC STUDY

  • 1 January 1981
    • journal article
    • research article
    • Vol. 40  (1) , 46-60
Abstract
Wallerian degeneration was investigated in the rat optic nerve after eye enucleation at 2, 5, 8 and 20 D.P.N. [days postnatal] (key stages), corresponding to the periods of premyelination, myelination and postmyelination. The incorporation of tritiated thymidine, and the subsequent radioautography of semithin sections allowed the identification and enumeration of labeled cells; it also allowed the computation of labeling indices of the different cell types (glioblasts, astrocytes, oligodendrocytes and microglia) in the operated and the contralateral nerve. The comparison of labeling indices and absolute numbers of labeled cells in each category suggests an increased transformation of glioblasts into astrocytes, an absence of differentiation and stabilization of oligodendrocytes due to the failure of the axonal signal, and a transformation of pericytes into interstitial microglia. The first 3 key stages (2,5 and 8 D.P.N.) are characterized by the integration of reactive gliosis, and more or less marked failure of myelination gliosis; however, the last one (20 D.P.N.) shows essentially a reactive gliosis. The modifications of the neural environment interfere with the genetic program of gliogenesis, illustrating the postnatal plasticity of the CNS.

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