Changes of ventricular ependyma and choroid plexus in experimental hydrocephalus, as observed by scanning electron microscopy.

Hydrocephalus was induced in rats by the injection of silicone oil or kaolin suspension into the cisterna magna. One to 5 weeks later the walls of the lateral ventricles were studied with the scanning electron microscope after killing the animals by perfusion fixation. In contrast to controls, the hydrocephalic animals killed 1 or 2 weeks after injection showed degeneration of ependymal cilia and infestation of the ependymal and choroid plexus surface with reactive cells, which presumably may be identified as Kolmer phagocytic cells by their ultrastructural features as studied by the transmission electron microscope. A coating of debris on the surface of the choroid plexus in the hydrocephalic animals possibly bears upon the ciliary degeneration with consequent deficiency of the clearing effect of ciliary movement. In the longer surviving hydrocephalic animals regeneration of cilia seemed to have occurred.