Abstract
Purpose::
Cortical blindness is found in human prion diseases. In this study, the effect of prion induced pathological changes in visual cortex was investigated in the brain of scrapie strain 139H-infected hamsters.
Methods::
Female weanling, Syrian hamsters, strain LVG/LAK, were used in scrapie infection; 19 were infected intracerebrally with brain homogenate of 139H scrapie-infected hamsters, 11 were inoculated with brain homogenate from normal hamster. The latter group served as control. At the end of scrapie incubation period (125 days after infection), paraffin sections from brains of scrapie and control hamsters were stained with hematoxylin and eosin (HE), and histological appearance was examined under light microscopy.
Results::
We observed brain atrophy and spongiform changes in brain areas related to the visual system in 139H scrapie-infected hamsters, but not in control hamsters. The lateral ventricles were enlarged and the visual cortexes were thinner in 139H-infected hamsters. The spongiform changes were found in lateral geniculate nucleus (DLG and VLG), superior colliculus (SC), and severe changes were in primary visual cortex (V1B, and V1M), and secondary visual cortex (V2L, V2ML, and V2MM). Variable prominent intracellular and extracellular round vacuoles of varying size were found in different cortical layers, especially in layers 2, 3, 4, and 5. Pathological changes in the columnar shape were found in some locations.
Conclusions::
We have identified histopathological changes in brain visual system in scrapie-infected hamsters comparable to prion-induced human cortical blindness. The pathological changes in the brain visual system have not been described previously in scrapie-infected hamsters.
Keywords: microscopy: light/fluorescence/immunohistochemistry • pathology: experimental • visual cortex