DETECTION OF APOPTOSIS INDUCED DNA CLEAVAGE IN SCRAPIE-INFECTED SHEEPBRAIN

The pathogenesis and molecular basis of nerve cell death which accompa nies scrapie infections in sheep are not well understood. Degeneration of neurons in culture caused by prion protein fragments has recently been reported to be consistent with mechanisms of cell death by apopto sis or programmed cell death. Apoptosis activation during prion-relate d encephalopathies has not yet been established in vivo. We report her e the detection of DNA damage consistent with apoptosis in the brain c ells of sheep infected with scrapie using laser scanning microscopic a nalysis of the single cell gel assay. We suggest that this DNA fragmen tation is the result of the activation of the mechanisms characteristi c of apoptotic cell death.