Neuroglia in central Wallerian Degeneration (ultrastructural and histoenzymatic studies)

In adult rabbits, unilateral enucleation was performed and morphological changes resulting from disconnection of the axons from their perikaryons of the optic nerve evaluated by means of light and electron microscopy. The morphological changes were compared with histochemically determined activities of several hydrolytic and oxidoreductive enzymes. The results obtained lead to the following conclusions: 1. Astroglial cells displaying increased enzymic activity of many hydrolases and oxidoreductases constitute the main cellular component of the mature optic nerve undergoing Wallerian degeneration. 2. Oligodendroglial cells of the degenerating optic nerve were found as well inside as in their usual position i.e. outside the axons. These cells displayed only slightly expressed morphological or histochemical signs of an increased biological activity. 3. In the mature optic nerve undergoing Wallerian degeneration some signs of remyelination i.e. formation of an aberrant myelin without proper connection to axons, were observed. 4. An intact functional connection between the perikaryons, the axons and myelin sheaths is in the mature optic nerve not indispensable for initiation of myelinogenesis during Wallerian degeneration.