The sequence of events involved in the neurodegeneration caused by transmis
sible spongiform encephalopathies is not yet known. Using a murine scrapie
model in which neurodegeneration in the hippocampus is restricted to the CA
2, we show an up-regulation of the proapoptotic markers Fas and caspase 3 e
arly in the incubation period prior to disease-specific prion protein (PrP)
deposition and clinical signs. These results suggest that activation of Fa
s and caspase 3 are involved in the early pathological sequence of events d
uring murine scrapie, and that these proapoptotic markers may be a specific
method for early detection of neurodegeneration. (C) 2001 Lippincott Willi
ams & Wilkins.