Oligodendroglial cell damage and demyelination in infant hydrocephalus. An electron microscopic study.

The hydropic changes of oligodendroglial cells have been examined by means of transmission electron microscopy in seventeen cases of human, mostly infant hydrocephalus and associated pathology. Hydropic oligodendrocytes exhibited dilated endoplasmic reticulum and nuclear envelope, edematous mitochondria, enlarged and fragmented Golgi complexes, dense bodies and nuclear chromatin homogenization. A process of nuclear pore disassembly, extrusion of nuclear heterochromatin and an apoptotic-like process were observed in some swollen oligodendrocytes. Some resting or quiescent oligodendrocytes were also observed in the edematous neuropil. Oligodendrocyte cell processes appeared atrophic, degenerated and isolated in the enlarged extracellular spaces. They did not show any association with neighbouring axons, and myelinated axons were not observed in the neuropil. These observations suggest demyelination in infant hydrocephalus.