Differential expression of Bax and Bcl-2 in the brains of hamsters infected with 263K scrapie agent

To study the mechanism(s) of neuronal cell death during scrapie infection, we investigated the expression of Bax and Bcl-2 in brains of hamsters infec ted with 263K scrapie agent The expression of Bcl-2 mRNA was significantly decreased in the brains of 263K scrapie-infected hamsters compared with con trols, whereas the expression levels of Bax mRNA were significantly increas ed in scrapie-infected brain. The levels of Bax and Bcl-2 proteins in brain s of scrapie and control animals reflected the difference in mRNA levels. I mmunoreactivity for Bax and Bcl-2 were found predominantly within neurons. In scrapie-infected brains, the number of neuronal cells positive for Bcl-2 was significantly lower in the hippocampal CA3 region and was decreased in the cerebral cortex, whereas the number of neuronal cells positive for Bax was significantly increased in both regions. The possibility that differen tial regulation of Bax and Bcl-2 expression may play an important role in n euronal cell death induced by scrapie infection is discussed. NeuroReport 1 1:1677-1682 (C) 2000 Lippincott Williams & Wilkins.