STRONG EXPRESSION OF GFAP MESSENGER-RNA IN RAT HIPPOCAMPUS AFTER A CLOSED-HEAD INJURY

WE investigated the spatiotemporal GFAP mRNA expression over a period of 11 days following brain injury in rats caused by impact acceleratio n, which is known to produce diffuse axonal injury (DAI). We observed widespread GFAP mRNA expression throughout the brain, which was more r apid and intense in the hippocampus. This expression was obvious in mo st animals 2 days after injury and appeared maximal at day 6. Although it decreased by day 11, the level of expression remained high compare d with control levels. We noted slight differences in time of onset an d the magnitude of the response between hippocampus and white matter s tructures or cortical areas. The different mechanisms able to trigger this response are discussed in regard to histopathological changes obs erved in DAI models.