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Electron microscopic studies of Wallerian degeneration in rat optic nerves. II. Astrocytes, oligodendrocytes and adventitial cells
Author(s) -
Vaughn James E.,
Pease Daniel C.
Publication year - 1970
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901400205
Subject(s) - wallerian degeneration , parenchyma , biology , degeneration (medical) , myelin , pathology , neuroglia , perivascular space , phagocytosis , anatomy , central nervous system , neuroscience , microbiology and biotechnology , medicine , botany
Fibrous astrocytes, oligodendrocytes and adventitial cells have been studied in rat optic nerves undergoing Wallerian degeneration. Postoperative survival times ranged from five hours to 250 days. Fibrous astrocytes fill the spaces made available by the removal of degenerating nerve fibers. In addition, some astrocytes apparently become phagocytic and engulf degenerating myelin fragments. This reaction is small in comparison to that of multipotential glia (Vaughn), Hinds and Skoff, '70, and it appears to be secondary to the role of astrocytes in scar formation. There is no evidence from this study suggesting that oligodendrocytes engulf degenerating nerve fibers. Indeed, they do not exhibit dramatic changes during fiber degeneration beyond forming aberrant myelin sheaths during the late postoperative stage. Similarly, adventitial cells generally remain unaltered although a few adventitial cells containing numerous inclusions are encountered in degenerating tissue. Adventitial cells are always located within the perivascular space and neither they nor leukocytes have been observed in transit from blood vessels into the neural parenchyma. Finally, an attempt is made to reconcile some of the diverse results concerning the origin of CNS phagocytes. It is suggested that in most pathological situations there is contribution of phagocytes from several different sources and the relative importance of each source is determined by the extent of degeneration and the degreed of inflammation.