Electron Microscopic and Other Observations on the Ependyma and Small Cerebral Blood Vessels in Mice and Rats Affected with Scrapie

Abstract

SUMMARY Unfixed preparations of ependymal cells from scrapie-affected mice and rats were examined for cilial movement; the rate of beating observed was similar to that of control animals. Electron microscopy of ependymal cells in scrapie cases showed them to be intact; large intracytoplasmic masses of amorphous material were observed. Myelinated nerve fibres immediately below the ependyma showed gross degenerative changes in scrapie. The small cerebral blood vessels in scrapie showed no regular abnormalities in their endothelial cells or basement membrane. There was little ultrastructural evidence that well recognized scrapie changes, such as neuronal abnormalities, were secondary to changes in ependyma or small blood vessels.