Wallerian degeneration of the optic nerve in light of histological and biochemical studies.

Wallerian degeneration of the rabbit optic nerve was produced by enucleation. The ultrastructure, enzyme histochemistry, myelin output as well as the lipid composition of degenerated nerve were studied. The obtained results lead to following conclusions: 1. Esterified cholesterol appeared in the lipid spectrum of myelin membranes undergoing Wallerian degeneration preceding a significant drop of myelin mass, without an involvement of lipomacrophages and without notable changes in the structure of myelin. 2. Esterification of cholesterol could function as a primary factor injuring the myelin membrane in central Wallerian degeneration, similarly as in other demyelinating processes. 3. Lipomacrophages occurring in the later stage of Wallerian degeneration of the optic nerve are of astroglial origin. 4. The slow progress of phagocytosis in the degenerating optic nerve might explain the almost unaffected pattern of myelin lipids in the course of Wallerian degeneration of this structure. 5. Lysocompounds play an important role in the pathomechanism of demyelination in the central nervous system including the optic nerve during further steps of myelin decay.