Subependymal plaques in scrapie-affected hamster brains--why are they so different from compact kuru plaques?
We report here routine thin-section and immunogold electron microscopic studies on diffuse plaques in scrapie-affected hamster brains. These plaques were not discernible by routine HE staining. Ultrastructurally, plaques were recognized as areas of low electron density containing haphazardly-oriented fibrils, but not as stellate compact structures typical of mouse scrapie models; hence we labelled them "loose plaques". Following immunohistochemistry at the electron microscopy level, fibrils within plaques were heavily decorated with PrP-conjugated gold particles. Loose plaques were located beneath the basal border of the ependymal cells and around blood vessels in the adjacent subependymal neuropil. When dystrophic neurites containing electron-dense inclusion bodies, some of them autophagic vacuoles [59], were seen within the plaque perimeter, they always remained PrP-negative. Some microglial cells were observed in close contact with PrP-positive plaques, and secondary lysosomes within these cells were heavily decorated with gold particles.
Sikorska
Beata
B
Department of Molecular Pathology and Neuropathology, Medical University of Lodz, Czechoslowacka Street 8/10, PL 92-216 Lodz, Poland.
Liberski
Paweł P
PP
Brown
Paul
P
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D006224:Cricetinae; D007150:Immunohistochemistry; D007729:Kuru / Q000473:pathology*; D046529:Microscopy, Electron, Transmission; D058225:Plaque, Amyloid / Q000648:ultrastructure*; D012608:Scrapie / Q000473:pathology*