Changes in Expression of BCL-2, BAX and ICE mRNA After Middle Cerebral Artery Occlusion in Rat

ABSTRACT

BACKGROUND: In order to delineate the involvement of apoptotic death in post-ischemic cerebral infarction, the temporal expressions of some apoptosis-regulating genes (BCL-2, BAX and ICE) were studied in the parietofrontal cortex of a rat following focal cerebral ischemia using a Northern blot analysis and RT-PCR. METHODS: Animals were decapitated at 0.5, 1, 2, 4, 8 and 24 hours following a middle cerebral artery occlusion (MCAO). RESULTS: With the use of Northern blotting, the expression of proto-oncogene BCL-2, the apoptosis-repressor gene, increased up to 4 hours after a MCAO and then recovered to the control level. In a RT-PCR analysis, the expression of BCL-2 increased up to 8 hours after the MCAO and then recovered to the control level at 24 hours. The expression of BAX, the apoptosis-effec-tor gene, was not altered by a MCAO in a Northern blot analysis. The expression of ICE, an cysteine protease gene, markedly decreased at 1 and 2 hours after the MCAO and then recovered to the control level. CONCLUSIONS: These results show that ischemic insults by a MCAO alter the expression of the apoptosis-regulating genes and support the notion that the apoptosis may have occurred in the post-ischemic cerebral infarction.