Degree Type

Thesis

Date of Award

2015

Degree Name

Master of Science

Department

Biomedical Sciences

First Advisor

Mary H. Greenlee

Abstract

Transmissible spongiform encephalopathies (TSEs) are caused by proteinaceous pathogens known as prions. These diseases develop slowly as the misfolded and protease-resistant prion protein, PrPSc, interacts with the normal cellular form, PrPC, a cell-surface protein found throughout the nervous system. This interaction causes the normal isoform to refold into PrPSc and accumulate within neurons, causing widespread degeneration. PrPSc accumulates in the retinas of many animals with TSEs. This accumulation and associated pathology may prove to be valuable for non-invasive, pre-mortem diagnostics. Our study aimed to investigate the course of retinal TSE pathology, using a mouse-adapted strain of the scrapie agent (RML) in C57Bl/6 mice. Mice were inoculated with RML-infected brain homogenate, either intracerebrally or intraperitoneally. Animals were euthanized and tissues collected every 30 days throughout the disease course, then prepared for standard histopathologic and immunohistochemical analysis. Immunohistochemistry was done on retinal tissues using antibodies against PrP (monoclonal antibody 6C2) and glial fibrillary acidic protein (GFAP), which is upregulated under conditions of retinal stress. Cell counts of the outer nuclear layer were done to quantify retinal degeneration. We found retinal PrPSc accumulation, stress, and degeneration are detectable after approximately 80% of the incubation period in mice, for all detection methods and inoculation routes. However, the associated pathology was somewhat lessened and the incubation period was prolonged in intraperitoneally-inoculated animals. This model will allow for more detailed study of PrPSc accumulation and neuronal cell death.

Copyright Owner

Melissa Lind

Language

en

File Format

application/pdf

File Size

49 pages

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