CELLULAR REACTION TO WALLERIAN DEGENERATION IN CENTRAL NERVOUS SYSTEM OF CAT

The fine structural features of Wallerian degeneration have been examined by electron microscopy of the cat central nervous system from 1 to 104 days following lesions. In the early stages of Wallerian degeneration, increased electron density is evident in the axoplasm of many axons. Myelin sheaths are occasionally seen to surround cells resembling oligodendroglia. Mitotic figures are present, occasionally in cells with glial filaments. Phagocytosis is carried out by cells resembling those found in the region of blood vessels. The phagocytes take up degenerating myelin and later the ingested myelin loses its characteristic structure and density and appers to be broken downto form lipid droplets. After 6-8 weeks, the phagocytes containing myelin remnants and lipid droplets are seen to abut capillaries. Later, the nervous parenchyma becomes filled with fibrillary glial processes, and phagocytes within the glial scar assume the morphological characteristics of microlia seen by light microscopy. Neither astroglial nor oligodendroglial cells appear to participate in the phagocytosis of degenerating myelin. © 1969.