Myelin lipids in Wallerian degeneration of the rabbit optic nerve.

Wallerian degeneration of the rabbit optic nerve was produced by enucleation and the myelin output as well as its lipid composition were studied. In spite of the marked drop in the myelin mass, occurring very soon after enucleation the lipid composition of the corresponding myelin fractions did not change appreciably, phosphatidylcholine being the most resistant lipid species. However, from the very beginning of the degenerating process there appeared in the myelin lipid spectrum marked amounts of cholesteryl esters and phosphatidic acids and in the later period elevated amounts of lysophosphatidylcholine. Enhanced esterification of cholesterol could function as an early primary factor injuring the myelin membrane, the lysocompounds may be involved at a later stage in the pathomechanism of myelin decomposition in the central nervous system.