Electron Microscopic Study of Ventricular Wall and Choroid Plexus in Experimentally-Induced Hydrocephalic Dogs

Ultrastructural findings of the ventricular wall and choroid plexus in experimentally-induced hydrocephalic dogs were observed with transmission and scanning electron microscopes. These findings were compared with intraventricular opening pressure, ventricular enlargement and ventricular permeability of tracers. Morphological change of the ependyma was slight at early stages, however, ependymal degeneration and enlargement of intercellular space were recognized at late stages. At this late stage, phenol-sulfon-phthalein (tracer) penetrates deeper into the ventricular wall and lanthanum (tracer) revealed development of an absorption pathway through extracellular space. Ultrastructural study in choroid plexus revealed dilatation of the extracellular space and significant deformity in degenerated epithelial cell. Tracer (lanthanum) study might suggest that the CSF absorption through the choroid plexus was not increased, but CSF secretion from the chroid plexus was disturbed in late hydrocephalus. Even in the late hydrocephalic dog, which showed no rapid ventricular enlargement, the development of CSF pathway induced destruction of neuron tissues including neuron. These facts indicate that the development of extracellular CSF pathway is harmful to the central nervous system, therefore, CSF drainage from ventricle is required to avoid destruction of the nervous tissue.