THE ROLE OF SCHWANN-CELLS DURING RETINAL GANGLION-CELL REGENERATION INDUCED BY PERIPHERAL-NERVE TRANSPLANTATION

Purpose. To investigate the key role of Schwann cells in retinal gangl ion cell regeneration elicited by peripheral nerve autotransplantation . Methods. Three kinds of autografts, Schwann-cell graft (intact sciat ic nerve, consisting of living Schwann cells and their basal laminae), Schwann-cell-eliminated graft (consisting mainly of Schwann cell basa l laminae) and partial Schwann-cell graft (consisting of basal laminae and diffusible factors secreted by Schwann cells) were prepared and a utotransplanted to the adult rat optic nerve. The membrane specializat ion between regenerating axons and Schwann cells was observed by elect ron microscopy. The expression of cell adhesion molecules was demonstr ated by Western blot analysis and immunohistochemistry. Results. Retin al ganglion cell axons were observed to regenerate into the Schwann-ce ll graft in contact with Schwann cells but not into the Schwann-cell-e liminated graft. The regeneration was not observed in the empty basal laminae of the partial Schwann-cell graft. Most of regenerating axons contacted astrocytes in the optic nerve segment, and Schwann cells in the graft. At the interface of regenerating axon and Schwann cell, in addition to immunoreactivity of N-CAM and L1, short focal tight juncti ons were observed. Conclusions. These results suggested that viable Sc hwann cells are good substrate for retinal ganglion cell regeneration, the intimate contact with viable Schwann cell surface plays an import ant role in retinal ganglion cell regeneration, tight junctions, and c ell adhesion molecules (L1, N-CAM) are observed between the regenerati ng axon and Schwann cell.