Electron microscopic study of central axons degeneration in traumatic human brain edema.

Cortical axonal degeneration was studied in seven cortical biopsies taken from patients with traumatic brain injuries. After one day of evolution of brain injury, myelinated axons underwent axonal swelling, myelin sheath vacuolization and distortion, rupture of axolemma and phagocytosis of myelin ovoids by neuroglial cells. After 8 days, the brain trauma induced an increased number of neurofilaments and augmented volume of oligodendroglial ad-axonal cytoplasm. Fifteen days after brain lesion, varicose fiber swelling and retraction of axoplasm were found with disappearance of axoplasmic organelles. After 21 days, the dark type of degeneration was observed in two cases. At this time, hypertrophic oligodendrocytes invaded the myelin sheath and phagocyted the axoplasmic content. After a long evolution time (2 years) the complete sequence of degeneration events could be followed from the initial axoplasmic changes to the advanced degeneration with phagocytosis by neuroglial and invading cells.