Optic nerve regeneration by peripheral nerve transplant.

We studied the morphology of regenerated retinal ganglion cells and their axons in adult rodents after axotomy and autologous transplantation of the sciatic nerve. Regenerated ganglion cells, backlabeled with rhodamine dextran, were of similar size to or larger than those of intact cells in control animals. Dendrites and occasionally axons as well showed abnormal morphologies in most cells, though some cells appeared quite normal. Cross-sections of the regenerated axons, observed by electron microscopy, were always attached to either the Schwann cell cytoplasm or the basal lamina. The immunoreactive structures to anti-laminin antibody were quite irregular in the cross-sectioned graft and, compared with those of the intact sciatic nerve, they were generally smaller. Their appearance closely resembled that of the basal lamina in the graft observed by electron microscopy. These observations, taken together, suggest that the laminin-rich basal laminae of Schwann cells are essentially important for the regeneration of retinal axons in adult rodents.